#### Sample records for warm magnetized atomic

1. Warm measurements of CBA superconducting magnets

SciTech Connect

Engelmann, R.; Herrera, J.; Kahn, S.; Kirk, H.; Willen, E.; Yamin, P.

1983-01-01

We present results on magnetic field measurements of CBA dipole magnets in the warm (normal conductor) and cryogenic (superconducting) states. We apply two methods for the warm measurements, a dc and ac method. We find a good correlation between warm and cryogenic measurements which lends itself to a reliable diagnosis of magnet field errors using warm measurements early in the magnet assembly process. We further find good agreement between the two warm measurement methods, both done at low currents.

2. Gradient Echo Quantum Memory in Warm Atomic Vapor

PubMed Central

Pinel, Olivier; Hosseini, Mahdi; Sparkes, Ben M.; Everett, Jesse L.; Higginbottom, Daniel; Campbell, Geoff T.; Lam, Ping Koy; Buchler, Ben C.

2013-01-01

Gradient echo memory (GEM) is a protocol for storing optical quantum states of light in atomic ensembles. The primary motivation for such a technology is that quantum key distribution (QKD), which uses Heisenberg uncertainty to guarantee security of cryptographic keys, is limited in transmission distance. The development of a quantum repeater is a possible path to extend QKD range, but a repeater will need a quantum memory. In our experiments we use a gas of rubidium 87 vapor that is contained in a warm gas cell. This makes the scheme particularly simple. It is also a highly versatile scheme that enables in-memory refinement of the stored state, such as frequency shifting and bandwidth manipulation. The basis of the GEM protocol is to absorb the light into an ensemble of atoms that has been prepared in a magnetic field gradient. The reversal of this gradient leads to rephasing of the atomic polarization and thus recall of the stored optical state. We will outline how we prepare the atoms and this gradient and also describe some of the pitfalls that need to be avoided, in particular four-wave mixing, which can give rise to optical gain. PMID:24300586

3. Warm inflation in presence of magnetic fields

SciTech Connect

Piccinelli, Gabriella; Ayala, Alejandro; Mizher, Ana Julia

2013-07-23

We present preliminary results on the possible effects that primordial magnetic fields can have for a warm inflation scenario, based on global supersymmetry, with a new-inflation-type potential. This work is motivated by two considerations: first, magnetic fields seem to be present in the universe on all scales which rises de possibility that they could also permeate the early universe; second, the recent emergence of inflationary models where the inflaton is not assumed to be isolated but instead it is taken as an interacting field, even during the inflationary expansion. The effects of magnetic fields are included resorting to Schwinger's proper time method.

4. Magnetic trap for thulium atoms

SciTech Connect

Sukachev, D D; Sokolov, A V; Chebakov, K A; Akimov, A V; Kolachevskii, N N; Sorokin, Vadim N

2011-08-31

For the first time ultra-cold thulium atoms were trapped in a magnetic quadrupole trap with a small field gradient (20 Gs cm{sup -1}). The atoms were loaded from a cloud containing 4x10{sup 5} atoms that were preliminarily cooled in a magneto-optical trap to the sub-Doppler temperature of 80 {mu}K. As many as 4x10{sup 4} atoms were trapped in the magnetic trap at the temperature of 40 {mu}K. By the character of trap population decay the lifetime of atoms was determined (0.5 s) and an upper estimate was obtained for the rate constant of inelastic binary collisions for spin-polarised thulium atoms in the ground state (g{sub in} < 10{sup -11}cm{sup 3} s{sup -1}). (magnetic traps)

5. Atomic and optical properties of warm dense copper

2015-09-01

The emission of x rays from warm dense matter is of great interest for both spectroscopic diagnostics and development of intense x-ray sources. We report the results from the collisional-radiative steady-state (CRSS) modeling of atomic and optical properties of copper plasmas at near-solid and solid-state density for a range of temperatures. The CRSS model is validated against the available data on the average charge state and shifts of energy levels in aluminum and the opacity and emissivity spectra of carbon and aluminum plasmas. The average charge states, number density of ion species, and free electrons as a function of temperature are investigated for the solid-density copper plasma. Due to the dense plasma environment the four outer electrons are found to be unbounded even in the low-temperature limit 1 eV . As the temperature changes from 1 to 100 eV, the predominant species vary from fivefold- to twelvefold-ionized copper ions. The opacity and emissivity spectra of dense copper plasmas are studied using the local thermodynamic equilibrium (LTE) and non-LTE approaches. It is found that the non-LTE effects are important in the spectral region of soft x rays emitted from the K shell. The emissivity in spectral lines is completely suppressed, indicating the importance of the energy-dissipating radiative processes in this soft x-ray region. Line broadening and redshifts of the K - and L -shell spectral lines toward higher wavelengths are observed with the increase of plasma density. These results have important implications for understanding the radiative properties of warm dense copper and can be useful for future experimental studies.

6. Atomic and optical properties of warm dense copper.

PubMed

2015-09-01

The emission of x rays from warm dense matter is of great interest for both spectroscopic diagnostics and development of intense x-ray sources. We report the results from the collisional-radiative steady-state (CRSS) modeling of atomic and optical properties of copper plasmas at near-solid and solid-state density for a range of temperatures. The CRSS model is validated against the available data on the average charge state and shifts of energy levels in aluminum and the opacity and emissivity spectra of carbon and aluminum plasmas. The average charge states, number density of ion species, and free electrons as a function of temperature are investigated for the solid-density copper plasma. Due to the dense plasma environment the four outer electrons are found to be unbounded even in the low-temperature limit ∼1eV. As the temperature changes from 1 to 100 eV, the predominant species vary from fivefold- to twelvefold-ionized copper ions. The opacity and emissivity spectra of dense copper plasmas are studied using the local thermodynamic equilibrium (LTE) and non-LTE approaches. It is found that the non-LTE effects are important in the spectral region of soft x rays emitted from the K shell. The emissivity in spectral lines is completely suppressed, indicating the importance of the energy-dissipating radiative processes in this soft x-ray region. Line broadening and redshifts of the K- and L-shell spectral lines toward higher wavelengths are observed with the increase of plasma density. These results have important implications for understanding the radiative properties of warm dense copper and can be useful for future experimental studies. PMID:26465577

7. Warm inflation in the presence of magnetic fields

Piccinelli, Gabriella; Snchez, ngel; Ayala, Alejandro; Mizher, Ana Julia

2014-10-01

We study the effects of primordial magnetic fields on the inflationary potential in the context of a warm inflation scenario. The model, based on global supersymmetry with a new-inflation-type potential and a coupling between the inflaton and a heavy intermediate superfield, is already known to preserve the flatness required for slow-roll conditions even after including thermal contributions. Here we show that the magnetic field makes the potential even flatter, retarding the transition and rendering it smoother.

8. Surface electromagnetic wave equations in a warm magnetized quantum plasma

SciTech Connect

Li, Chunhua; Yang, Weihong; Wu, Zhengwei; Chu, Paul K.

2014-07-15

Based on the single-fluid plasma model, a theoretical investigation of surface electromagnetic waves in a warm quantum magnetized inhomogeneous plasma is presented. The surface electromagnetic waves are assumed to propagate on the plane between a vacuum and a warm quantum magnetized plasma. The quantum magnetohydrodynamic model includes quantum diffraction effect (Bohm potential), and quantum statistical pressure is used to derive the new dispersion relation of surface electromagnetic waves. And the general dispersion relation is analyzed in some special cases of interest. It is shown that surface plasma oscillations can be propagated due to quantum effects, and the propagation velocity is enhanced. Furthermore, the external magnetic field has a significant effect on surface wave's dispersion equation. Our work should be of a useful tool for investigating the physical characteristic of surface waves and physical properties of the bounded quantum plasmas.

9. Warm and dense stellar matter under strong magnetic fields

SciTech Connect

Rabhi, A.; Panda, P. K.; Providencia, C.

2011-09-15

We investigate the effects of strong magnetic fields on the equation of state of warm stellar matter as it may occur in a protoneutron star. Both neutrino-free and neutrino-trapped matter at a fixed entropy per baryon are analyzed. A relativistic mean-field nuclear model, including the possibility of hyperon formation, is considered. A density-dependent magnetic field with a magnitude of 10{sup 15} G at the surface and not more than 3x10{sup 18} G at the center is considered. The magnetic field gives rise to a neutrino suppression, mainly at low densities, in matter with trapped neutrinos. It is shown that a hybrid protoneutron star will not evolve into a low-mass black hole if the magnetic field is strong enough and the magnetic field does not decay. However, the decay of the magnetic field after cooling may give rise to the formation of a low-mass black hole.

10. Magnetic trapping of circular Rydberg atoms

Anderson, David; Schwarzkopf, Andrew; Raithel, Georg

2013-05-01

Circular Rydberg atoms exhibit a unique combination of properties: long lifetimes ( n5), large magnetic moments and angular momenta (|m | = l =n - 1), and no first order Stark shift. Here, n , l and m are the principal, orbital and magnetic quantum numbers, respectively. Several of these features have made circular Rydberg atoms attractive for a number of applications including photon-atom interaction and Rydberg interaction experiments. We present here the realization of a magnetic trap for circular Rydberg atoms. The Rydberg-atom trap is characterized using state-selective electric-field ionization, direct spatial imaging of the atom distributions and time-of-flight analysis of the ion signal. At room temperature, we observe 70 percent of the trapped atoms remaining after 6ms. We measure an increase of the center-of-mass trap oscillation frequency by the expected factor of √{ | m | }. Simulations of the state-evolution of circular-state atoms in our magnetic trap, held at 300K radiation temperature, are performed and results are in good agreement with the observed phenomena. This work was supported by the AFOSR (FA9550-10-1-0453).

11. Warm Magnetic Field Measurements of LARP HQ Magnet

SciTech Connect

Caspi, S; Cheng, D; Deitderich, D; Felice, H; Ferracin, P; Hafalia, R; Joseph, J; Lizarazo, J; Martchevskii, M; Nash, C; Sabbi, G L; Vu, C; Schmalzle, J; Ambrosio, G; Bossert, R; Chlachidze, G; DiMarco, J; Kashikhin, V

2011-03-28

The US-LHC Accelerator Research Program is developing and testing a high-gradient quadrupole (HQ) magnet, aiming at demonstrating the feasibility of Nb{sub 3}Sn technologies for the LHC luminosity upgrade. The 1 m long HQ magnet has a 120 mm bore with a conductor-limited gradient of 219 T/m at 1.9 K and a peak field of 15 T. HQ includes accelerator features such as alignment and field quality. Here we present the magnetic measurement results obtained at LBNL with a constant current of 30 A. A 100 mm long circuit-board rotating coil developed by FNAL was used and the induced voltage and flux increment were acquired. The measured b{sub 6} ranges from 0.3 to 0.5 units in the magnet straight section at a reference radius of 21.55 mm. The data reduced from the numerical integration of the raw voltage agree with those from the fast digital integrators.

12. Atom trapping with a thin magnetic film

SciTech Connect

Boyd, Micah; Streed, Erik W.; Medley, Patrick; Campbell, Gretchen K.; Mun, Jongchul; Ketterle, Wolfgang; Pritchard, David E.

2007-10-15

We have created a {sup 87}Rb Bose-Einstein condensate in a magnetic trapping potential produced by a hard disk platter written with a periodic pattern. Cold atoms were loaded from an optical dipole trap and then cooled to Bose-Einstein condensation on the surface with radio-frequency evaporation. Fragmentation of the atomic cloud due to imperfections in the magnetic structure was observed at distances closer than 40 {mu}m from the surface. Attempts to use the disk as an atom mirror showed dispersive effects after reflection.

13. Ultracold atoms in strong synthetic magnetic fields

Ketterle, Wolfgang

2015-03-01

The Harper Hofstadter Hamiltonian describes charged particles in the lowest band of a lattice at high magnetic fields. This Hamiltonian can be realized with ultracold atoms using laser assisted tunneling which imprints the same phase into the wavefunction of neutral atoms as a magnetic field dose for electrons. I will describe our observation of a bosonic superfluid in a magnetic field with half a flux quantum per lattice unit cell, and discuss new possibilities for implementing spin-orbit coupling. Work done in collaboration with C.J. Kennedy, G.A. Siviloglou, H. Miyake, W.C. Burton, and Woo Chang Chung.

14. Quantum computing with magnetically interacting atoms

SciTech Connect

Derevianko, Andrei; Cannon, Caleb C.

2004-12-01

We propose a scalable quantum-computing architecture based on cold atoms confined to sites of a tight optical lattice. The lattice is placed in a nonuniform magnetic field and the resulting Zeeman sublevels define qubit states. Microwave pulses tuned to space-dependent resonant frequencies are used for individual addressing. The atoms interact via magnetic-dipole interactions allowing implementation of a universal controlled-NOT gate. The resulting gate operation times for alkalis-metals are on the order of milliseconds, much faster then the anticipated decoherence times. Single qubit operations take about 10 {mu}s. Analysis of motional decoherence due to NOT operations is given. We also comment on the improved feasibility of the proposed architecture with complex open-shell atoms, such as Cr, Eu, and metastable alkaline-earth atoms with larger magnetic moments.

15. Storage and retrieval of thermal light in warm atomic vapor

SciTech Connect

Cho, Young-Wook; Kim, Yoon-Ho

2010-09-15

We report slowed propagation and storage and retrieval of thermal light in warm rubidium vapor using the effect of electromagnetically induced transparency (EIT). We first demonstrate slowed propagation of the probe thermal light beam through an EIT medium by measuring the second-order correlation function of the light field using the Hanbury-Brown-Twiss interferometer. We also report an experimental study on the effect of the EIT slow-light medium on the temporal coherence of thermal light. Finally, we demonstrate the storage and retrieval of the thermal light beam in the EIT medium. The direct measurement of the photon number statistics of the retrieved light field shows that the photon number statistics are preserved during the storage and retrieval processes.

16. Influence of magnetically trapped hot ions on warm plasma flowing

SciTech Connect

1995-12-31

Interesting and unexpected phenomenon was found on heating plasma experiments on trap {open_quotes}AMBAL-YU{close_quotes}: neutral beam injection results in decrease of target plasma density without change of its shape. The {open_quotes}AMBAL-YU{close_quotes} device is a classical mirror with minimum-B. Neutral beams injected into the trap perpendicularly to the magnetic field form hot-ion plasma. In the initial stage of hot-ion accumulation, target plasma is a plasma generated by gas-discharge source located behind the trap. Plasma penetrates into the trap along magnetic field lines. Injection leads to decrease of target plasma density (up to 2.5 times). Plasma density sudden leap moving from injection region to gas-discharge source had been observed. A considerable increase of energy of ions leaving the trap was experimentally registered. Plasma potential had been changed. It was cleared out that this effect is not explained by transversal losses of plasma or passing of momentum from beams to plasma. Rise of activity on ion cyclotron fluctuations had not been registered. The physical situation we wish to model is that of a warm plasma flowing along magnetic field lines in the presence of a magnetically trapped species of hot ions. Let us consider the plasma stream in the frames of two liquids magnetohydrodynamics. We consider the following set of momentum equations presented by Braginskiy in a slightly different form.

17. Ladder-type electromagnetically induced transparency using nanofiber-guided light in a warm atomic vapor

Jones, D. E.; Franson, J. D.; Pittman, T. B.

2015-10-01

We demonstrate ladder-type electromagnetically induced transparency (EIT) using an optical nanofiber suspended in a warm rubidium vapor. The signal and control fields are both guided along the nanofiber, which enables strong nonlinear interactions with the surrounding atoms at relatively low powers. Transit-time broadening is found to be a significant EIT decoherence mechanism in this tightly confined waveguiding geometry. Nonetheless, we observe significant EIT and controlled polarization rotation using control-field powers of only a few microwatts in this relatively robust warm-atom nanofiber system.

18. Analysis of a magnetically trapped atom clock

SciTech Connect

2006-11-15

We consider optimization of a rubidium atom clock that uses magnetically trapped Bose condensed atoms in a highly elongated trap, and determine the optimal conditions for minimum Allan variance of the clock using microwave Ramsey fringe spectroscopy. Elimination of magnetic field shifts and collisional shifts are considered. The effects of spin-dipolar relaxation are addressed in the optimization of the clock. We find that for the interstate interaction strength equal to or larger than the intrastate interaction strengths, a modulational instability results in phase separation and symmetry breaking of the two-component condensate composed of the ground and excited hyperfine clock levels, and this mechanism limits the clock accuracy.

19. Atomization methods for forming magnet powders

SciTech Connect

Sellers, C.H.; Branagan, D.J.; Hyde, T.A.

2000-02-08

The invention encompasses methods of utilizing atomization, methods for forming magnet powders, methods for forming magnets, and methods for forming bonded magnets. The invention further encompasses methods for simulating atomization conditions. In one aspect, the invention includes an atomization method for forming a magnet powder comprising: (a) forming a melt comprising R{sub 2.1}Q{sub 13.9}B{sub 1}, Z and X, wherein R is a rare earth element; X is an element selected from the group consisting of carbon, nitrogen, oxygen and mixtures thereof; Q is an element selected from the group consisting of Fe, Co and mixtures thereof; and Z is an element selected from the group consisting of Ti, Zr, Hf and mixtures thereof; (b) atomizing the melt to form generally spherical alloy powder granules having an internal structure comprising at least one of a substantially amorphous phase or a substantially nanocrystalline phase; and (c) heat treating the alloy powder to increase an energy product of the alloy powder; after the heat treatment, the alloy powder comprising an energy product of at least 10 MGOe. In another aspect, the invention includes a magnet comprising R, Q, B, Z and X, wherein R is a rare earth element; X is an element selected from the group consisting of carbon, nitrogen, oxygen and mixtures thereof; Q is an element selected from the group consisting of Fe, Co and mixtures thereof; and Z is an element selected from the group consisting of Ti, Zr, Hf and mixtures thereof; the magnet comprising an internal structure comprising R{sub 2.1}Q{sub 13.9}B{sub 1}.

20. Atomization methods for forming magnet powders

DOEpatents

Sellers, Charles H. (Idaho Falls, ID); Branagan, Daniel J. (Idaho Falls, ID); Hyde, Timothy A. (Idaho Falls, ID)

2000-01-01

The invention encompasses methods of utilizing atomization, methods for forming magnet powders, methods for forming magnets, and methods for forming bonded magnets. The invention further encompasses methods for simulating atomization conditions. In one aspect, the invention includes an atomization method for forming a magnet powder comprising: a) forming a melt comprising R.sub.2.1 Q.sub.13.9 B.sub.1, Z and X, wherein R is a rare earth element; X is an element selected from the group consisting of carbon, nitrogen, oxygen and mixtures thereof; Q is an element selected from the group consisting of Fe, Co and mixtures thereof; and Z is an element selected from the group consisting of Ti, Zr, Hf and mixtures thereof; b) atomizing the melt to form generally spherical alloy powder granules having an internal structure comprising at least one of a substantially amorphous phase or a substantially nanocrystalline phase; and c) heat treating the alloy powder to increase an energy product of the alloy powder; after the heat treatment, the alloy powder comprising an energy product of at least 10 MGOe. In another aspect, the invention includes a magnet comprising R, Q, B, Z and X, wherein R is a rare earth element; X is an element selected from the group consisting of carbon, nitrogen, oxygen and mixtures thereof; Q is an element selected from the group consisting of Fe, Co and mixtures thereof; and Z is an element selected from the group consisting of Ti, Zr, Hf and mixtures thereof; the magnet comprising an internal structure comprising R.sub.2.1 Q.sub.13.9 B.sub.1.

1. Zeeman relaxation of magnetically trapped Eu atoms

SciTech Connect

Suleimanov, Yury V.

2010-02-15

We perform rigorous quantum mechanical calculations for collisions between magnetically trapped Eu atoms to elucidate the results of recent experimental studies. We show that the relaxation from the maximally stretched m{sub s}=7/2 level is entirely determined by the magnetic dipole-dipole interaction and analyze the role of the electronic spin-exchange interaction in transitions from the lower-energy Zeeman levels. The relaxation of the m{sub s}=5/2 state is shown to be very sensitive to the spin-exchange parameter that determines the splitting between the lowest electronic states of the Eu dimer. We suggest that cold collision experiments with trapped atoms can be used as a tool for obtaining accurate information on the electronic spin anisotropy in complex molecules such as Eu{sub 2}.

2. Atomic Calculations and Laboratory Measurements Relevant to X-ray Warm Absorbers

NASA Technical Reports Server (NTRS)

Kallman, Tim; Bautista, M.; Palmeri, P.

2007-01-01

This viewgraph document reviews the atomic calculations and the measurements from the laboratory that are relevant to our understanding of X-Ray Warm Absorbers. Included is a brief discussion of the theoretical and the experimental tools. Also included is a discussion of the challenges, and calculations relevant to dielectronic recombination, photoionization cross sections, and collisional ionization. A review of the models is included, and the sequence that the models were applied.

3. Atomic scale evolution of magnetic anisotropies

Bland, J. A. C.; Hope, S.; Tselepi, M.; Choi, B.

1998-03-01

The results of in situ studies of the evolution of the magnetic anisotropy of Co(100) and Co(110) epitaxial films are discussed. It is shown that uniaxial magnetic anisotropies are the generic signature of symmetry breaking atomic and nm scale structures, e.g. steps, clusters, islands revealed by scanning tunnelling microscopy (STM) studies, and are strongly affected by nonmagnetic overlayers. However, the thickness dependent behaviour is surprisingly complex, with strong changes in anisotropy behaviour occurring with submonolayer depositions of nonmagnetic overlayers. These effects cannot be understood within the usual framework of the Nel model but are discussed in terms of several contributing mechanisms, e.g. strain, dipolar interactions and edge and surface anisotropies.

4. Tailoring the chiral magnetic interaction between two individual atoms

Khajetoorians, A. A.; Steinbrecher, M.; Ternes, M.; Bouhassoune, M.; Dos Santos Dias, M.; Lounis, S.; Wiebe, J.; Wiesendanger, R.

2016-02-01

Chiral magnets are a promising route towards dense magnetic storage technology due to their inherent nano-scale dimensions and energy efficient properties. Engineering chiral magnets requires atomic-level control of the magnetic exchange interactions, including the Dzyaloshinskii-Moriya interaction, which defines a rotational sense for the magnetization of two coupled magnetic moments. Here we show that the indirect conduction electron-mediated Dzyaloshinskii-Moriya interaction between two individual magnetic atoms on a metallic surface can be manipulated by changing the interatomic distance with the tip of a scanning tunnelling microscope. We quantify this interaction by comparing our measurements to a quantum magnetic model and ab-initio calculations yielding a map of the chiral ground states of pairs of atoms depending on the interatomic separation. The map enables tailoring the chirality of the magnetization in dilute atomic-scale magnets.

5. Tailoring the chiral magnetic interaction between two individual atoms.

PubMed

Khajetoorians, A A; Steinbrecher, M; Ternes, M; Bouhassoune, M; Dos Santos Dias, M; Lounis, S; Wiebe, J; Wiesendanger, R

2016-01-01

Chiral magnets are a promising route towards dense magnetic storage technology due to their inherent nano-scale dimensions and energy efficient properties. Engineering chiral magnets requires atomic-level control of the magnetic exchange interactions, including the Dzyaloshinskii-Moriya interaction, which defines a rotational sense for the magnetization of two coupled magnetic moments. Here we show that the indirect conduction electron-mediated Dzyaloshinskii-Moriya interaction between two individual magnetic atoms on a metallic surface can be manipulated by changing the interatomic distance with the tip of a scanning tunnelling microscope. We quantify this interaction by comparing our measurements to a quantum magnetic model and ab-initio calculations yielding a map of the chiral ground states of pairs of atoms depending on the interatomic separation. The map enables tailoring the chirality of the magnetization in dilute atomic-scale magnets. PMID:26902332

6. Tailoring the chiral magnetic interaction between two individual atoms

PubMed Central

Khajetoorians, A. A.; Steinbrecher, M.; Ternes, M.; Bouhassoune, M.; dos Santos Dias, M.; Lounis, S.; Wiebe, J.; Wiesendanger, R.

2016-01-01

Chiral magnets are a promising route towards dense magnetic storage technology due to their inherent nano-scale dimensions and energy efficient properties. Engineering chiral magnets requires atomic-level control of the magnetic exchange interactions, including the Dzyaloshinskii–Moriya interaction, which defines a rotational sense for the magnetization of two coupled magnetic moments. Here we show that the indirect conduction electron-mediated Dzyaloshinskii–Moriya interaction between two individual magnetic atoms on a metallic surface can be manipulated by changing the interatomic distance with the tip of a scanning tunnelling microscope. We quantify this interaction by comparing our measurements to a quantum magnetic model and ab-initio calculations yielding a map of the chiral ground states of pairs of atoms depending on the interatomic separation. The map enables tailoring the chirality of the magnetization in dilute atomic-scale magnets. PMID:26902332

7. Hydrogen atom in intense magnetic field.

NASA Technical Reports Server (NTRS)

Canuto, V.; Kelly, D. C.

1972-01-01

The structure of a hydrogen atom situated in an intense magnetic field is investigaged. Three approaches are employed. An elementary Bohr picture establishes a crucial magnetic field strength, H sub a approximately equal to 5 x 10 to the 9th G. Fields in excess of H sub a are intense in that they are able to modify the characteristic atomic scales of length and binding energy. A second approach solves the Schrodinger equation by a combination of variational methods and perturbation theory. It yields analytic expressions for the wave functions and energy eigenvalues. A third approach determines the energy eigenvalues by reducing the Schrodinger equation to a one-dimensional wave equation, which is then solved numerically. Energy eigenvalues are tabulated for field strengths of 2 x 10 to the 10th G and 2 x 10 to the 12th G. It is found that at 2 x 10 to the 12th G the lowest energy eigenvalue is changed from -13.6 to about -180 eV in agreement with previous variational computations.

8. Observation of Magnetically Induced Trap Loss of Ultracold Thulium Atoms

Kalganova, E. S.; Vishnyakova, G. A.; Golovizin, A. A.; Tregubov, D. O.; Sukachev, D. D.; Akimov, A. V.; Kolachevsky, N. N.; Khabarova, K. Yu.; Sorokin, V. N.

2015-09-01

We report the observation of influence of homogeneous magnetic field on an optical lattice losses of ultracold thulium atoms. The atomic cloud temperature was T = 15 mK. The dependence of trap population on a value of magnetic field has a broad resonance in the low-field region with a center at B = 0.4 G. We also have measured a decrease of optical lattice lifetime in a presence of resonance magnetic field. The observed magnetically-induced trap losses are assumed to be Feshbach resonance which is a dependence of an atomic scattering length on magnetic field.

9. Multiple focusing magnets used for velocity selection of atoms

NASA Technical Reports Server (NTRS)

1970-01-01

Computer techniques are used in calculating velocity selection of hydrogen atoms for use in maser frequency standard. Technique permits designer to resolve design problems of multiple focusing magnets employed in atomic velocity selection. There is excellent agreement with hand calculations in constant magnetic moment approximation.

10. Cold and ultracold Rydberg atoms in strong magnetic fields

Pohl, T.; Sadeghpour, H. R.; Schmelcher, P.

2009-12-01

Cold Rydberg atoms exposed to strong magnetic fields possess unique properties which open the pathway for an intriguing many-body dynamics taking place in Rydberg gases, consisting of either matter or anti-matter systems. We review both the foundations and recent developments of the field in the cold and ultracold regime where trapping and cooling of Rydberg atoms have become possible. Exotic states of moving Rydberg atoms, such as giant dipole states, are discussed in detail, including their formation mechanisms in a strongly magnetized cold plasma. Inhomogeneous field configurations influence the electronic structure of Rydberg atoms, and we describe the utility of corresponding effects for achieving tightly trapped ultracold Rydberg atoms. We review recent work on large, extended cold Rydberg gases in magnetic fields and their formation in strongly magnetized ultracold plasmas through collisional recombination. Implications of these results for current antihydrogen production experiments are pointed out, and techniques for the trapping and cooling of such atoms are investigated.

11. Atomic hydrogen storage. [cryotrapping and magnetic field strength

NASA Technical Reports Server (NTRS)

Woollam, J. A. (Inventor)

1980-01-01

Atomic hydrogen, for use as a fuel or as an explosive, is stored in the presence of a strong magnetic field in exfoliated layered compounds such as molybdenum disulfide or an elemental layer material such as graphite. The compound is maintained at liquid temperatures and the atomic hydrogen is collected on the surfaces of the layered compound which are exposed during delamination (exfoliation). The strong magnetic field and the low temperature combine to prevent the atoms of hydrogen from recombining to form molecules.

12. Application of magnetic atom induced bound states in superconducting gap for chemical identification of single magnetic atoms

Ji, Shuai-Hua; Zhang, Tong; Fu, Ying-Shuang; Chen, Xi; Jia, Jin-Feng; Xue, Qi-Kun; Ma, Xu-Cun

2010-02-01

Elemental identification at single atom level has been achieved with a low temperature scanning tunneling microscope. Magnetic atoms (Mn or Cr) adsorbed on a superconducting Pb substrate induce a set of well-defined resonance states inside the superconductor gap in scanning tunneling spectroscopy. We show that these localized characteristic bound states could serve as fingerprint for chemical identification of the corresponding atoms, similar to atomic/molecular spectra widely used in optical spectrometry. The experiment demonstrates a technique for element-resolved spectroscopy with simultaneous atomic-level spatial resolution. The influence of magnetic impurity concentration on the bound states has also been investigated.

13. Manipulating Neutral Atoms in Chip-Based Magnetic Traps

NASA Technical Reports Server (NTRS)

Aveline, David; Thompson, Robert; Lundblad, Nathan; Maleki, Lute; Yu, Nan; Kohel, James

2009-01-01

Several techniques for manipulating neutral atoms (more precisely, ultracold clouds of neutral atoms) in chip-based magnetic traps and atomic waveguides have been demonstrated. Such traps and waveguides are promising components of future quantum sensors that would offer sensitivities much greater than those of conventional sensors. Potential applications include gyroscopy and basic research in physical phenomena that involve gravitational and/or electromagnetic fields. The developed techniques make it possible to control atoms with greater versatility and dexterity than were previously possible and, hence, can be expected to contribute to the value of chip-based magnetic traps and atomic waveguides. The basic principle of these techniques is to control gradient magnetic fields with suitable timing so as to alter a trap to exert position-, velocity-, and/or time-dependent forces on atoms in the trap to obtain desired effects. The trap magnetic fields are generated by controlled electric currents flowing in both macroscopic off-chip electromagnet coils and microscopic wires on the surface of the chip. The methods are best explained in terms of examples. Rather than simply allowing atoms to expand freely into an atomic waveguide, one can give them a controllable push by switching on an externally generated or a chip-based gradient magnetic field. This push can increase the speed of the atoms, typically from about 5 to about 20 cm/s. Applying a non-linear magnetic-field gradient exerts different forces on atoms in different positions a phenomenon that one can exploit by introducing a delay between releasing atoms into the waveguide and turning on the magnetic field.

14. Wave breaking of nonlinear electron oscillations in a warm magnetized plasma

SciTech Connect

Pramanik, Sourav; Maity, Chandan; Chakrabarti, Nikhil

2014-02-15

Wave breaking phenomena of nonlinear electron oscillations around a homogeneous background of massive ions have been studied in a warm magnetized plasma by using Lagrangian variables. An inhomogeneity in the background magnetic field is shown to induce phase mixing and thus breaking of the oscillations. A nonlinear analysis in Lagrangian variables predicts that wave breaking may disappear above a critical value of the electron temperature. An estimate for the critical temperature has been provided.

15. Quantum molecular dynamics study of expanded beryllium: Evolution from warm dense matter to atomic fluid

PubMed Central

Li, Dafang; Liu, Haitao; Zeng, Siliang; Wang, Cong; Wu, Zeqing; Zhang, Ping; Yan, Jun

2014-01-01

By performing quantum molecular dynamics (QMD) simulations, we investigate the equation of states, electrical and optical properties of the expanded beryllium at densities two to one-hundred lower than the normal solid density, and temperatures ranging from 5000 to 30000 K. With decreasing the density of Be, the optical response evolves from the one characteristic of a simple metal to the one of an atomic fluid. By fitting the optical conductivity spectra with the Drude-Smith model, it is found that the conducting electrons become localized at lower densities. In addition, the negative derivative of the electrical resistivity on temperature at density about eight lower than the normal solid density demonstrates that the metal to nonmetal transition takes place in the expanded Be. To interpret this transition, the electronic density of states is analyzed systematically. Furthermore, a direct comparison of the Rosseland opacity obtained by using QMD and the standard opacity code demonstrates that QMD provides a powerful tool to validate plasma models used in atomic physics approaches in the warm dense matter regime. PMID:25081816

16. Atomic beam focusing with a curved magnetic mirror

Merimeche, H.

2006-09-01

Reflective atom optics has been experimentally realized with a continuous flux of cold atoms by using a magnetized videotape. We have studied the behaviour of a slow atomic beam with a velocity of 20 m s-1 incident at different angles on the surface of a curved magnetic mirror. Focusing of the beam has been demonstrated and this induces an amplification up to a factor 3 of the fluorescence emitted by the atoms around the focal point. We deduced the shape of our reflector from the focal length measurements and show that the result is completely consistent with those obtained from the reflection of a red diode laser beam on the curved mirror.

17. Magnetic properties of single Ni atoms on Cu2 N

Prueser, Henning; Gill, Toby G.; Warner, Ben; Hirjibehedin, Cyrus F.

2014-03-01

When a magnetic atom is placed onto a conducting surface its properties may change considerably due to interactions with the substrate. This interaction may be reduced by introducing a thin decoupling layer between the atom and the underlying metal. One general consequence of placing a magnetic atom on a surface is magnetic anisotropy, where angular momentum along a certain direction is energetically preferred. Although recent studies of atomic scale nanostructures have been able to measure the magnetic anisotropy for atomically precise configurations, a clear understanding of the dramatic differences observed for different atomic spins has not yet emerged. Using scanning tunneling microscopy and spectroscopy, we study the case of single Ni atoms deposited on copper nitride (Cu2N) islands formed in a Cu(001) surface. As in prior studies, we find that the observed magnetic behavior strongly depends on the binding site of the adsorbate. For Ni, however, surprisingly large anisotropy is observed on a nitrogen binding site; this is in stark contrast to the behavior observed for Mn, Fe, and Co, which display evidence of magnetic anisotropy on Cu sites. We explore the possible origins for this behavior as well as the implications for other transition metal adsorbates.

18. Induce magnetism into silicene by embedding transition-metal atoms

SciTech Connect

Sun, Xiaotian; Wang, Lu E-mail: yyli@suda.edu.cn; Lin, Haiping; Hou, Tingjun; Li, Youyong E-mail: yyli@suda.edu.cn

2015-06-01

Embedding transition-metal (TM) atoms into nonmagnetic nanomaterials is an efficient way to induce magnetism. Using first-principles calculations, we systematically investigated the structural stability and magnetic properties of TM atoms from Sc to Zn embedded into silicene with single vacancy (SV) and double vacancies (DV). The binding energies for different TM atoms correlate with the TM d-shell electrons. Sc, Ti, and Co show the largest binding energies of as high as 6 eV, while Zn has the lowest binding energy of about 2 eV. The magnetic moment of silicene can be modulated by embedding TM atoms from V to Co, which mainly comes from the 3d orbitals of TM along with partly contributions from the neighboring Si atoms. Fe atom on SV and Mn atom on DV have the largest magnetic moment of more than 3 μB. In addition, we find that doping of N or C atoms on the vacancy site could greatly enhance the magnetism of the systems. Our results provide a promising approach to design silicene-based nanoelectronics and spintronics device.

19. Note: Manipulation of supersonic atomic beams with static magnetic fields.

PubMed

Gardner, Jamie; Castillo-Garza, Rodrigo; Raizen, Mark G

2013-09-01

The inhomogeneous magnetic field of a permanent-magnet planar Halbach array is used to either deflect or to specularly reflect a supersonic beam of neutral atoms. Metastable neon and helium beams are tested to experimentally evaluate the performance of this array in a range of configurations. Results are compared with numerical simulations and the device is presented as a high precision tool for the manipulation of neutral atom beams. PMID:24028135

20. Note: Manipulation of supersonic atomic beams with static magnetic fields

Gardner, Jamie; Castillo-Garza, Rodrigo; Raizen, Mark G.

2013-09-01

The inhomogeneous magnetic field of a permanent-magnet planar Halbach array is used to either deflect or to specularly reflect a supersonic beam of neutral atoms. Metastable neon and helium beams are tested to experimentally evaluate the performance of this array in a range of configurations. Results are compared with numerical simulations and the device is presented as a high precision tool for the manipulation of neutral atom beams.

1. Detection of brain magnetic fields with an atomic magnetometer

Xia, Hui; Hoffman, Dan; Baranga, Andrei; Romalis, Michael

2006-05-01

We report detection of magnetic fields generated by evoked brain activity with an atomic magnetometer. The measurements are performed with a high-density potassium magnetometer operating in a spin-exchange relaxation free regime. Compared to SQUID magnetometers which so far have been the only detectors capable of measuring the magnetic fields from the brain, atomic magnetometers have the advantages of higher sensitivity and spatial resolution, simple multi-channel recording, and no need for cryogenics. Using a multi-channel photodetector array we recorded magnetic fields from the brain correlated with an audio tone administered with a non-magnetic earphone. The spatial map of the magnetic field gives information about the location of the brain region responding to the auditory stimulation. Our results demonstrate the atomic magnetometer as an alternative and low cost technique for brain imaging applications, without using cryogenic apparatus.

2. TECHNICAL DESIGN NOTE: Magnetic moment measurement of magnetic nanoparticles using atomic force microscopy

Park, J.-W.; Yoo, I. S.; Chang, W.-S.; Lee, E.-C.; Ju, H.; Chung, B. H.; Kim, B. S.

2008-01-01

Magnetic moment per unit mass of magnetic nanoparticles was found by using the atomic force microscope (AFM). The mass of the nanoparticles was acquired from the resonance frequency shift of the particle-attached AFM probe and magnetic force measurement was also carried out with the AFM. Combining with magnetic field strength, the magnetic moment per unit mass of the nanoparticles was determined as a function of magnetic field strength.

3. Production and detection of atomic hexadecapole at Earth's magnetic field.

PubMed

Acosta, V M; Auzinsh, M; Gawlik, W; Grisins, P; Higbie, J M; Jackson Kimball, D F; Krzemien, L; Ledbetter, M P; Pustelny, S; Rochester, S M; Yashchuk, V V; Budker, D

2008-07-21

Optical magnetometers measure magnetic fields with extremely high precision and without cryogenics. However, at geomagnetic fields, important for applications from landmine removal to archaeology, they suffer from nonlinear Zeeman splitting, leading to systematic dependence on sensor orientation. We present experimental results on a method of eliminating this systematic error, using the hexadecapole atomic polarization moment. In particular, we demonstrate selective production of the atomic hexadecapole moment at Earth's magnetic field and verify its immunity to nonlinear Zeeman splitting. This technique promises to eliminate directional errors in all-optical atomic magnetometers, potentially improving their measurement accuracy by several orders of magnitude. PMID:18648462

4. Atomic spin orbit coupling synthesized with gradient magnetic fields

Luo, Xinyu; Wu, Lingna; Wang, Ruquan; You, L.

2015-09-01

Spin orbit coupling (SOC) for neutral atoms can be synthesized with pulsed or time modulating gradient magnetic field (GMF). This is confirmed through the studies of collective dipole oscillations for a spin-1 atomic condensate in a harmonic trap after abruptly turning on SOC and adiabatically adjusted equilibrium states when SOC strength is slowly ramped up. Further measurements reveal that SOC can be enhanced when the GMF modulation frequency approaches harmonic trap frequency. Additionally, we discuss how the technique of pulsed GMF can be used to synthesize space-period magnetic fields, or magnetic lattices.

5. Emerging magnetic order in platinum atomic contacts and chains

Strigl, Florian; Espy, Christopher; Bckle, Maximilian; Scheer, Elke; Pietsch, Torsten

2015-02-01

The development of atomic-scale structures revealing novel transport phenomena is a major goal of nanotechnology. Examples include chains of atoms that form while stretching a transition metal contact or the predicted formation of magnetic order in these chains, the existence of which is still debated. Here we report an experimental study of the magneto-conductance (MC) and anisotropic MC with atomic-size contacts and mono-atomic chains of the nonmagnetic metal platinum. We find a pronounced and diverse MC behaviour, the amplitude and functional dependence change when stretching the contact by subatomic distances. These findings can be interpreted as a signature of local magnetic order in the chain, which may be of particular importance for the application of atomic-sized contacts in spintronic devices of the smallest possible size.

6. Emerging magnetic order in platinum atomic contacts and chains

PubMed Central

Strigl, Florian; Espy, Christopher; Bckle, Maximilian; Scheer, Elke; Pietsch, Torsten

2015-01-01

The development of atomic-scale structures revealing novel transport phenomena is a major goal of nanotechnology. Examples include chains of atoms that form while stretching a transition metal contact or the predicted formation of magnetic order in these chains, the existence of which is still debated. Here we report an experimental study of the magneto-conductance (MC) and anisotropic MC with atomic-size contacts and mono-atomic chains of the nonmagnetic metal platinum. We find a pronounced and diverse MC behaviour, the amplitude and functional dependence change when stretching the contact by subatomic distances. These findings can be interpreted as a signature of local magnetic order in the chain, which may be of particular importance for the application of atomic-sized contacts in spintronic devices of the smallest possible size. PMID:25649440

7. Magnetism and surface structure of atomically controlled ultrathin metal films.

SciTech Connect

Shiratsuchi, Yu.; Yamamoto, M.; Bader, S. D.; Materials Science Division; Osaka Univ.

2007-01-01

We review the correlation of magnetism and surface structure in ultrathin metal films, including the tailoring of novel magnetic properties using atomic scale control of the nanostructure. We provide an overview of modern fabrication and characterization techniques used to create and explore these fascinating materials, and highlight important phenomena of interest. We also discuss techniques that control and characterize both the magnetic and structural properties on an atomic scale. Recent advances in the development and applications of these techniques allow nanomagnetism to be investigated in an unprecedented manner. A system cannot necessarily retain a two-dimensional structure as it enters the ultrathin region, but it can transform into a three-dimensional, discontinuous structure due to the Volmer-Weber growth mechanism. This structural transformation can give rise to superparamagnetism. During this evolution, competing factors such as interparticle interactions and the effective magnetic anisotropy govern the magnetic state. These magnetic parameters are influenced by the nanostructure of the film. In particular, controlling the magnetic anisotropy is critical for determining the magnetic properties. Surface effects play especially important roles in influencing both the magnitude and direction of the magnetic anisotropy in ultrathin films. By properly altering the surface structure, the strength and direction of the magnetic anisotropy are controlled via spin-orbit and/or dipole interactions.

8. Prototype development of a warm bore insert for the LHC magnet measurements

Clari, F.; Dunkel, O.; Genet, M.; Gregory, Ch.; Sievers, P.

1994-07-01

To allow the measurements of the superconducting LHC magnets up to their nominal field with well-proven, standard techniques, easy access into the apertures is required at ambient temperature and atmospheric pressure. A warm bore anti-cryostat is inserted into the cold bore vacuum pipe of the magnet, where the evacuated radial gap between these two parts serves as thermal insulation. To allow for maximum accessible cross-section during the measurements, the small radial gap of 3.5 mm has to accommodate superinsulation, support spacers and electrical heaters for the thermalization. Design aspects, related to the high magnetic fields, quenches, mechanical loads, vacuum, reliability and ease of handling have to be addressed. The design of the anti-cryostat and the cryogenic test of a prototype model are described. The heat load on the cold mass of the magnet by this prototype was below one watt per meter.

9. Chemically induced magnetism in atomically precise gold clusters.

PubMed

Krishna, Katla Sai; Tarakeshwar, Pilarisetty; Mujica, Vladimiro; Kumar, Challa S S R

2014-03-12

Comparative theoretical and experimental investigations are reported into chemically induced magnetism in atomically-precise, ligand-stabilized gold clusters Au25 , Au38 and Au55 . The results indicate that [Au25 (PPh3 )10 (SC12 H25 )5 Cl2 ](2+) and Au38 (SC12 H25 )24 are diamagnetic, Au25 (SC2 H4 Ph)18 is paramagnetic, and Au55 (PPh3 )12 Cl6 , is ferromagnetic at room temperature. Understanding the magnetic properties resulting from quantum size effects in such atomically precise gold clusters could lead to new fundamental discoveries and applications. PMID:24150895

10. Dynamical localization: Hydrogen atoms in magnetic and microwave fields

SciTech Connect

Benvenuto, F.; Casati, G.; Shepelyansky, D.L.

1997-03-01

We show that dynamical localization for excited hydrogen atoms in magnetic and microwave fields takes place at quite low microwave frequency ({omega}n{sup 3}{lt}1). Estimates of the localization length are given for different parameter regimes, showing that the quantum delocalization border drops significantly as compared to the case of zero magnetic field. This opens up broad possibilities for laboratory investigations. {copyright} {ital 1997} {ital The American Physical Society}

11. Ultracold Dipolar Molecules Composed of Strongly Magnetic Atoms

Frisch, A.; Mark, M.; Aikawa, K.; Baier, S.; Grimm, R.; Petrov, A.; Kotochigova, S.; Qumner, G.; Lepers, M.; Dulieu, O.; Ferlaino, F.

2015-11-01

In a combined experimental and theoretical effort, we demonstrate a novel type of dipolar system made of ultracold bosonic dipolar molecules with large magnetic dipole moments. Our dipolar molecules are formed in weakly bound Feshbach molecular states from a sample of strongly magnetic bosonic erbium atoms. We show that the ultracold magnetic molecules can carry very large dipole moments and we demonstrate how to create and characterize them, and how to change their orientation. Finally, we confirm that the relaxation rates of molecules in a quasi-two-dimensional geometry can be reduced by using the anisotropy of the dipole-dipole interaction and that this reduction follows a universal dipolar behavior.

12. Reactions between NO/+/ and metal atoms using magnetically confined afterglows

NASA Technical Reports Server (NTRS)

Lo, H. H.; Clendenning, L. M.; Fite, W. L.

1977-01-01

A new method of studying thermal energy ion-neutral collision processes involving nongaseous neutral atoms is described. A long magnetic field produced by a solenoid in a vacuum chamber confines a thermal-energy plasma generated by photoionization of gas at very low pressure. As the plasma moves toward the end of the field, it is crossed by a metal atom beam. Ionic products of ion-atom reactions are trapped by the field and both the reactant and product ions move to the end of the magnetic field where they are detected by a quadrupole mass filter. The cross sections for charge transfer between NO(+) and Na, Mg, Ca, and Sr and that for rearrangement between NO(+) and Ca have been obtained. The charge-transfer reaction is found strongly dominant over the rearrangement reaction that forms metallic oxide ions.

13. Inelastic tunneling spectroscopy for magnetic atoms and the Kondo resonance.

PubMed

Goldberg, E C; Flores, F

2013-06-01

The interaction between a single magnetic atom and the metal environment (including a magnetic field) is analyzed by introducing an ionic Hamiltonian combined with an effective crystal-field term, and by using a Green-function equation of motion method. This approach describes the inelastic electron tunneling spectroscopy and the Kondo resonances as due to atomic spin fluctuations associated with electron co-tunneling processes between the leads and the atom. We analyze in the case of Fe on CuN the possible spin fluctuations between states with S=2 and 3/2 or 5/2 and conclude that the experimentally found asymmetries in the conductance with respect to the applied bias, and its marked structures, are well explained by the 2?3/2 spin fluctuations. The case of Co is also considered and shown to present, in contrast with Fe, a resonance at the Fermi energy corresponding to a Kondo temperature of 6K. PMID:23587848

14. Atomic relaxation effects on magnetism in CoPt nanoalloys

Dupuis, V.; Tamion, A.

2014-06-01

We describe the magnetism of CoPt clusters upon annealing-driven transition to chemically ordered L10-like phase. In one hand, X-ray magnetic circular dichroism (XMCD) investigations at each L2 3 edge, revealed a significant increase of both spin and orbital of Co and Pt magnetic moments after thermal ordering transition. In the other hand, reversely to the bulk alloys, a limited Magnetic Anisotropy Energy (MAE) enhancement has been obtained from SQUID magnetometry measurements on the same chemically ordered CoPt nanomagnets samples. In this paper, we relate such magnetic behaviour to element-specific dependence of the local atomic relaxations in nanoalloys, described from extended x-ray absorption fine structure (EXAFS) experiments.

15. Humid Medieval Warm Period recorded by magnetic characteristics of sediments from Gonghai Lake, Shanxi, North China

Liu, J.; Chen, F.; Chen, J.; Xia, D.; Xu, Q.; Wang, Z.; Li, Y.

2011-12-01

Variations in monsoon strength, moisture or precipitation in eastern China during the MWP reflected by different climatic records have shown apparent discrepancies. Here detailed environmental magnetic investigations and mineralogical analyses were conducted on lacustrine sediments of Core GH09B1 (2.8 m long) from Gonghai Lake, Shanxi, North China, concerning the monsoon history during the MWP. The results demonstrate that the main magnetic mineral is magnetite. The sediments with relatively high magnetic mineral concentrations were characterized by relatively fine magnetic grain sizes, which were formed in a period of relatively strong pedogenesis and high precipitation. In contrast, the sediments with low magnetic mineral concentrations reflected an opposite process. The variations of magnetic parameters in Gonghai Lake sediments were mainly controlled by the degree of pedogenesis in the lake drainage basin, which further indicated the strength of the Asian summer monsoon. The variations in the ? and S-300 parameters of the core clearly reveal the Asian summer monsoon history over the last 1200 years in the study area, suggesting generally abundant precipitation and a strong summer monsoon during the Medieval Warm Period (MWP, AD 910-1220), which is supported by pollen evidence. Furthermore, this 3-6-year resolution environmental magnetic record indicates a dry event around AD 980-1050, interrupting the generally humid MWP. The summer monsoon evolution over the last millennium recorded by magnetic parameters in sediments from Gonghai Lake correlates well with historical documentation (North China) and speleothem oxygen isotopes (Wanxiang Cave), as well as precipitation modeling results (extratropical East Asia), which all indicate a generally humid MWP within which centennial-scale moisture variability existed. It is thus demonstrated that environmental magnetic parameters could be used as an effective proxy for monsoon climate variations in high-resolution lacustrine sediments.

16. Spin nutation induced by atomic motion in a magnetic lattice

SciTech Connect

Kobayashi, Y.; Shiraishi, Y.; Hatakeyama, A.

2010-12-15

An atom moving in a spatially periodic field experiences a temporally periodic perturbation and undergoes a resonance transition between atomic internal states when the transition frequency is equal to the atomic velocity divided by the field period. We demonstrated that spin nutation was induced by this resonant transition in a polarized rubidium (Rb) atomic beam passing through a magnetic lattice. The lattice was produced by current flowing through an array of parallel wires crossing the beam. This array structure, reminiscent of a multiwire chamber for particle detection, allowed the Rb beam to pass through the lattice at a variety of incident angles. The dephasing of spin nutation was reduced by varying the incident angle.

17. Dynamics of neutral atoms in artificial magnetic field

Yu, Zi-Fa; Hu, Fang-Qi; Zhang, Ai-Xia; Xue, Ju-Kui

2016-02-01

Cyclotron dynamics of neutral atoms in a harmonic trap potential with artificial magnetic field is studied theoretically. The cyclotron orbit is obtained analytically and confirmed numerically. When the external harmonic potential is absent, artificial magnetic field can result in the singly periodic circular motion of Bose gas with the emergence of a Lorentz-like force, which is similar to particles with electric charge moving in a magnetic field. However, the coupling between artificial magnetic field and harmonic trap potential leads to rich and complex cyclotron trajectory, which depends on √{B2 + 1 }, where B is the rescaled artificial magnetic field. When √{B2 + 1 } is a rational number, the cyclotron orbit is multiply periodic and closed. However, when √{B2 + 1 } is an irrational number, the cyclotron orbit is quasiperiodic, i.e., the cyclotron motion of Bose gas is limited in a annular region, and eventually, the motion is ergodic in this region. Furthermore, the cyclotron orbits also depend on the initial conditions of Bose gas. Thus, the cyclotron dynamics of Bose gas can be manipulated in a controllable way by changing the artificial magnetic field, harmonic trap potential and initial conditions. Our results provide a direct theoretical evidence for the cyclotron dynamics of neutral atoms in the artificial gauge field.

18. Pulse pumping high spatial resolution atomic magnetic microscopy

Hu, Xuyang; Huang, Haichao; Chen, Lin; Dong, Haifeng

2015-05-01

Atom vapor magnetometer is currently the most sensitive magnetometer with the fundamental sensitivity of 0 . 012 fT .cm-3 .Hz-1/2 and a measured sensitivity of 0 . 16 fT .Hz-1/2 with a measurement volume of 0 . 45cm3. However, the spatial resolution is limited to millimeter scale even with the buffer gas because of the atom diffusion. We present a way to limit atom diffusion range and improve the spatial resolution by using short pulse pumping and CCD detector. The diffusion model and spin-exchange relaxation time are used to calculate theoretically the relation between the spatial resolution and the magnetic sensitivity, which shows that sensitivity-resolution product of the atomic magnetic microscopy (MM) is smaller than that of other MMs, such as scanning SQUID MM, NV diamond MM and BEC MM. The pulse pumping is generated using Photodigm DBR 180TS laser which can output a short pulse light of 300 ns with a power of 180 mW. The magnetic image is obtained from the laser spot images received by a Manta G145 NIR CCD. This work was supported in part by the NSF of China (61074171, 61273067) and National Program on Key Basic Research Project of China (2012CB934104).

19. Effect of a primordial magnetic field on the inflaton decay process in a warm inflation scenario

Bastero-Gil, M.; Piccinelli, G.; Sanchez, A.

2015-11-01

Magnetic fields appear everywhere in the Universe. Their widespread presence at high redshifts and very large scales suggests that their origin could be primordial. In particular, their presence during the inflationary epoch can certainly not be ruled out. In the warm inflation scenario, the coupling of the inflaton to other bosonic and fermionic fields gives rise to dissipative effects that modify the inflationary dynamics. Since primordial magnetic fields could have an effect on both the effective inflationary potential and the inflaton decay process, their contribution must be considered together with the finite temperature corrections. We review here their effect on the inflationary potential and present preliminary results of their intervention in the dissipation process.

20. Atomically thin dilute magnetism in Co-doped phosphorene

Seixas, L.; Carvalho, A.; Castro Neto, A. H.

2015-04-01

Two-dimensional dilute magnetic semiconductors can provide fundamental insights into the very nature of magnetic order and their manipulation through electron and hole doping. Besides the fundamental interest, due to the possibility of control of charge density, they can be extremely important in spintronics applications such as spin valve and spin-based transistors. In this paper, we studied a two-dimensional dilute magnetic semiconductor consisting of a phosphorene monolayer doped with cobalt atoms in substitutional and interstitial defects. We show that these defects can be stabilized and are electrically active. Furthermore, by including holes or electrons by a potential gate, the exchange interaction and magnetic order can be engineered, and may even induce a ferromagnetic-to-antiferromagnetic phase transition in p -doped phosphorene. At a Co concentration of 2.7%, we estimate a Curie temperature of TCMF A=466 K in the mean-field approximation.

1. Reinventing atomic magnetic simulations with spin-orbit coupling

DOE PAGESBeta

Perera, Meewanage Dilina N.; Eisenbach, Markus; Nicholson, Don M.; Stocks, George Malcolm; Landau, David P.

2016-02-10

We propose a powerful extension to the combined molecular and spin dynamics method that fully captures the coupling between the atomic and spin subsystems via spin-orbit interactions. Moreover, the foundation of this method lies in the inclusion of the local magnetic anisotropies that arise as a consequence of the lattice symmetry breaking due to phonons or crystallographic defects. By using canonical simulations of bcc iron with the system coupled to a phonon heat bath, we show that our extension enables the previously unachievable angular momentum exchange between the atomic and spin degrees of freedom.

2. Simple basis for hydrogenic atoms in magnetic fields

SciTech Connect

Gallas, J.A.C.

1984-01-01

A field-dependent hydrogenic basis is used to obtain the evolution of the energy spectrum of atoms in strong (approx.10/sup 8/ G) and uniform magnetic fields. The basis allows results to be derived analytically. Numerical values for the first 13 excited states of hydrogen are found to be in very good agreement with much more elaborate calculations of Smith et al. and of Brandi. In addition, the possibility of having a remnant type of degeneracy in the presence of the magnetic field is investigated.

3. Relativistic variational calculations for hydrogenic atoms in strong magnetic fields

Chen, Z.; Goldman, S. P.

1991-08-01

A Relativistic finite-basis-set method is used to calculate the ground-state energy of hydrogenic atoms in a strong magnetic field with 109G?B?1012G, for several values of the nucelar charge Z. A modified Slater-type basis set with different values of the total angular momentum is used. Even though an upper bound on the energy can not be obtained with the basis set, a good convergence is achieved. With magnetic field B fixed, the convergence is better for large nuclear charge Z where relativistic effects are more important. For very strong B and small Z, a modified Landau-type basis set is required.

4. Soft magnetic composites manufactured by warm co-extrusion of bulk metallic glass and steel powders

SciTech Connect

Johnson, Francis; Raber, Thomas R.; Zabala, Robert J.; Buresh, Steve J.; Tanico, Brian

2013-05-07

Soft magnetic composites of Fe-based bulk metallic glass and low-alloy steel have been manufactured by warm co-extrusion of precursor powders at temperatures within the supercooled liquid region of the glass. Composites were manufactured with amorphous volume fractions of 75%, 67%, and 100%. Full consolidation of the constituent powders was observed with the bulk metallic glass remaining substantially amorphous. The composite electrical resistivity was observed to be anisotropic with a resistivity of 79 {mu}{Omega} cm measured transverse to the extrusion axis in a sample with 75% amorphous volume fraction. A 0-3 connectivity pattern with the low-resistivity steel phase embedded in a 3-dimensionally connected high-resistivity bulk metallic glass phase was observed with scanning electron microscopy. This confirms that the flow characteristics of the bulk metallic glass and the steel powders were comparable during extrusion at these temperatures. The saturation magnetization of 1.3 T was consistent with the volume weighted average of the saturation magnetization of the two phases. A relatively high quasistatic coercivity of 8 Oe was measured and is likely due to slight crystallization of the bulk metallic glass as well as domain wall pinning at prior particle boundaries. Careful control of the thermal environment during the extrusion process is required to minimize glass crystallization and achieve the desired balance of magnetic and electrical properties.

5. Guiding and Trapping of Rydberg atoms in a linear magnetic atom guide

Hempel, Cornelius; Traxler, Mallory; Vaidya, Varun; Raithel, Georg

2009-05-01

We describe an experimental approach and present results on the dynamics of Rydberg atoms in a high-gradient magnetic guiding and trapping apparatus. The setup consists of two parallel current-carrying wires providing a quadrupole trapping potential with a gradient of 2.7 kG.cm-1 at its center. A Ioffe-Pritchard type trap can be formed by superposition of an inhomogeneous longitudinal bias field. Rubidium Rydberg atoms are excited using the two-photon transition 5S1/2 -> 5P3/2 -> nL, where n and L are principal and angular-momentum quantum numbers. An ion-imaging insert allows for time-delayed and spatially resolved detection of the excited atoms and their motion within the trapping potential. The excitation geometry is suitable for coherent, highly efficient population of circular Rydberg levels using adiabatic transfer in crossed magnetic and time-dependent electric fields. Circular-state atoms have long radiative lifetimes and small electric polarizabilities, making them ideal for Rydberg-atom trapping experiments and for studies that require long coherence times.

6. Designing Frustrated Quantum Magnets with Laser-Dressed Rydberg Atoms

Glaetzle, Alexander W.; Dalmonte, Marcello; Nath, Rejish; Gross, Christian; Bloch, Immanuel; Zoller, Peter

2015-05-01

We show how a broad class of lattice spin-1 /2 models with angular- and distance-dependent couplings can be realized with cold alkali atoms stored in optical or magnetic trap arrays. The effective spin-1 /2 is represented by a pair of atomic ground states, and spin-spin interactions are obtained by admixing van der Waals interactions between fine-structure split Rydberg states with laser light. The strengths of the diagonal spin interactions as well as the "flip-flop," and "flip-flip" and "flop-flop" interactions can be tuned by exploiting quantum interference, thus realizing different spin symmetries. The resulting energy scales of interactions compare well with typical temperatures and decoherence time scales, making the exploration of exotic forms of quantum magnetism, including emergent gauge theories and compass models, accessible within state-of-the-art experiments.

7. Designing frustrated quantum magnets with laser-dressed Rydberg atoms.

PubMed

Glaetzle, Alexander W; Dalmonte, Marcello; Nath, Rejish; Gross, Christian; Bloch, Immanuel; Zoller, Peter

2015-05-01

We show how a broad class of lattice spin-1/2 models with angular- and distance-dependent couplings can be realized with cold alkali atoms stored in optical or magnetic trap arrays. The effective spin-1/2 is represented by a pair of atomic ground states, and spin-spin interactions are obtained by admixing van der Waals interactions between fine-structure split Rydberg states with laser light. The strengths of the diagonal spin interactions as well as the "flip-flop," and "flip-flip" and "flop-flop" interactions can be tuned by exploiting quantum interference, thus realizing different spin symmetries. The resulting energy scales of interactions compare well with typical temperatures and decoherence time scales, making the exploration of exotic forms of quantum magnetism, including emergent gauge theories and compass models, accessible within state-of-the-art experiments. PMID:25978228

8. Atomic magnetic gradiometer for room temperature high sensitivity magnetic field detection

DOEpatents

Xu,Shoujun; Lowery, Thomas L.; Budker, Dmitry; Yashchuk, Valeriy V.; Wemmer, David E.; Pines, Alexander

2009-08-11

A laser-based atomic magnetometer (LBAM) apparatus measures magnetic fields, comprising: a plurality of polarization detector cells to detect magnetic fields; a laser source optically coupled to the polarization detector cells; and a signal detector that measures the laser source after being coupled to the polarization detector cells, which may be alkali cells. A single polarization cell may be used for nuclear magnetic resonance (NMR) by prepolarizing the nuclear spins of an analyte, encoding spectroscopic and/or spatial information, and detecting NMR signals from the analyte with a laser-based atomic magnetometer to form NMR spectra and/or magnetic resonance images (MRI). There is no need of a magnetic field or cryogenics in the detection step, as it is detected through the LBAM.

9. Magnetism in single metalloorganic complexes formed by atom manipulation.

PubMed

Choi, T; Badal, M; Loth, S; Yoo, J-W; Lutz, C P; Heinrich, A J; Epstein, A J; Stroud, D G; Gupta, J A

2014-03-12

The magnetic properties of molecular structures can be tailored by chemical synthesis or bottom-up assembly at the atomic scale. We used scanning tunneling microscopy to study charge and spin transfer in individual complexes of transition metals with the charge acceptor, tetracyanoethylene (TCNE). The complexes were formed on a thin insulator, Cu2N on Cu(100), by manipulation of individual atoms and molecules. The Cu2N layer decouples the complexes from Cu electron density, enabling direct imaging of the TCNE molecular orbitals as well as spin-flip inelastic electron tunneling spectroscopy. Results were obtained at low temperature down to 1 K and in magnetic fields up to 7 T in order to resolve splitting of spin states in the complexes. We also performed spin-polarized density functional theory calculations to compare with the experimental data. Our results indicate that charge transfer to TCNE leads to a change in spin magnitude, Kondo resonance, and magnetic anisotropy for the metal atoms. PMID:24490665

10. Atom interferometry in space: Thermal management and magnetic shielding

Milke, Alexander; Kubelka-Lange, Andr; Grlebeck, Norman; Rievers, Benny; Herrmann, Sven; Schuldt, Thilo; Braxmaier, Claus

2014-08-01

Atom interferometry is an exciting tool to probe fundamental physics. It is considered especially apt to test the universality of free fall by using two different sorts of atoms. The increasing sensitivity required for this kind of experiment sets severe requirements on its environments, instrument control, and systematic effects. This can partially be mitigated by going to space as was proposed, for example, in the Spacetime Explorer and Quantum Equivalence Principle Space Test (STE-QUEST) mission. However, the requirements on the instrument are still very challenging. For example, the specifications of the STE-QUEST mission imply that the Feshbach coils of the atom interferometer are allowed to change their radius only by about 260 nm or 2.6 10-4 % due to thermal expansion although they consume an average power of 22 W. Also Earth's magnetic field has to be suppressed by a factor of 105. We show in this article that with the right design such thermal and magnetic requirements can indeed be met and that these are not an impediment for the exciting physics possible with atom interferometers in space.

11. Atom interferometry in space: Thermal management and magnetic shielding

SciTech Connect

Milke, Alexander; Kubelka-Lange, André; Gürlebeck, Norman Rievers, Benny; Herrmann, Sven; Schuldt, Thilo; Braxmaier, Claus

2014-08-15

Atom interferometry is an exciting tool to probe fundamental physics. It is considered especially apt to test the universality of free fall by using two different sorts of atoms. The increasing sensitivity required for this kind of experiment sets severe requirements on its environments, instrument control, and systematic effects. This can partially be mitigated by going to space as was proposed, for example, in the Spacetime Explorer and Quantum Equivalence Principle Space Test (STE-QUEST) mission. However, the requirements on the instrument are still very challenging. For example, the specifications of the STE-QUEST mission imply that the Feshbach coils of the atom interferometer are allowed to change their radius only by about 260 nm or 2.6 × 10{sup −4} % due to thermal expansion although they consume an average power of 22 W. Also Earth's magnetic field has to be suppressed by a factor of 10{sup 5}. We show in this article that with the right design such thermal and magnetic requirements can indeed be met and that these are not an impediment for the exciting physics possible with atom interferometers in space.

12. Atom interferometry in space: thermal management and magnetic shielding.

PubMed

Milke, Alexander; Kubelka-Lange, Andr; Grlebeck, Norman; Rievers, Benny; Herrmann, Sven; Schuldt, Thilo; Braxmaier, Claus

2014-08-01

Atom interferometry is an exciting tool to probe fundamental physics. It is considered especially apt to test the universality of free fall by using two different sorts of atoms. The increasing sensitivity required for this kind of experiment sets severe requirements on its environments, instrument control, and systematic effects. This can partially be mitigated by going to space as was proposed, for example, in the Spacetime Explorer and Quantum Equivalence Principle Space Test (STE-QUEST) mission. However, the requirements on the instrument are still very challenging. For example, the specifications of the STE-QUEST mission imply that the Feshbach coils of the atom interferometer are allowed to change their radius only by about 260?nm or 2.6 10(-4)?% due to thermal expansion although they consume an average power of 22?W. Also Earth's magnetic field has to be suppressed by a factor of 10(5). We show in this article that with the right design such thermal and magnetic requirements can indeed be met and that these are not an impediment for the exciting physics possible with atom interferometers in space. PMID:25173244

13. Simulating and detecting artificial magnetic fields in trapped atoms

SciTech Connect

Rosenkranz, Matthias; Klein, Alexander; Jaksch, Dieter

2010-01-15

A Bose-Einstein condensate exhibiting a nontrivial phase induces an artificial magnetic field in immersed impurity atoms trapped in a stationary, ring-shaped optical lattice. We present an effective Hamiltonian for the impurities for two condensate setups: the condensate in a rotating ring and in an excited rotational state in a stationary ring. We use Bogoliubov theory to derive analytical formulas for the induced artificial magnetic field and the hopping amplitude in the limit of low condensate temperature where the impurity dynamics is coherent. As methods for observing the artificial magnetic field we discuss time-of-flight imaging and mass current measurements. Moreover, we compare the analytical results of the effective model to numerical results of a corresponding two-species Bose-Hubbard model. We also study numerically the clustering properties of the impurities and the quantum chaotic behavior of the two-species Bose-Hubbard model.

14. Ultracold Dipolar Molecules Composed of Strongly Magnetic Atoms.

PubMed

Frisch, A; Mark, M; Aikawa, K; Baier, S; Grimm, R; Petrov, A; Kotochigova, S; Qumner, G; Lepers, M; Dulieu, O; Ferlaino, F

2015-11-13

In a combined experimental and theoretical effort, we demonstrate a novel type of dipolar system made of ultracold bosonic dipolar molecules with large magnetic dipole moments. Our dipolar molecules are formed in weakly bound Feshbach molecular states from a sample of strongly magnetic bosonic erbium atoms. We show that the ultracold magnetic molecules can carry very large dipole moments and we demonstrate how to create and characterize them, and how to change their orientation. Finally, we confirm that the relaxation rates of molecules in a quasi-two-dimensional geometry can be reduced by using the anisotropy of the dipole-dipole interaction and that this reduction follows a universal dipolar behavior. PMID:26613437

15. Sheath and boundary conditions in a collisional magnetized warm electronegative plasma

SciTech Connect

Li, Jing-ju; Department of Physics, China University of Mining and Technology, Xuzhou, Jiangsu 221116 ; Ma, J. X.; Wei, Zi-an

2013-06-15

The characteristics of a weakly collisional sheath in a warm electronegative plasma in the presence of an oblique magnetic field are investigated using a fluid model including the effects of ionization and ion-neutral collisions. The general sheath criterion imposed on the entrance velocity component of the positive ions perpendicular to the wall at the sheath-presheath edge is derived and discussed. It is shown that the boundary conditions are crucial to the sheath structure. Without including the entrance velocity components parallel to the wall, a pulse-like structure in the positive-ion density distribution near the sheath-presheath edge appears if the magnetic field is strong. With inclusion of all velocity components at the edge, the pulse-like structure disappears, resulting in a smooth sheath profile. It is also found that increasing the temperature and decreasing the concentration of the negative ions will increase the sheath thickness, and increasing the magnetic field will decrease the sheath thickness.

16. Thermometry of Red Blood Cell Concentrate: Magnetic Resonance Decoding Warm Up Process

PubMed Central

Wagner, Thomas; Kozma, Noemi; Roland, Jrg; Schllnast, Helmut; Ebner, Franz; Lanzer, Gerhard

2013-01-01

Purpose Temperature is a key measure in human red blood cell concentrate (RBC) quality control. A precise description of transient temperature distributions in RBC units removed from steady storage exposed to ambient temperature is at present unknown. Magnetic resonance thermometry was employed to visualize and analyse RBC warm up processes, to describe time courses of RBC mean, surface and core temperatures by an analytical model, and to determine and investigate corresponding model parameters. Methods Warm-up processes of 47 RBC units stored at 16C and exposed to 21.25C ambient temperature were investigated by proton resonance frequency thermometry. Temperature distributions were visualized and analysed with dedicated software allowing derivation of RBC mean, surface and core temperature-time courses during warm up. Time-dependence of mean temperature was assumed to fulfil a lumped capacitive model of heat transfer. Time courses of relative surface and core temperature changes to ambient temperature were similarly assumed to follow shifted exponential decays characterized by a time constant and a relative time shift, respectively. Results The lumped capacitive model of heat transfer and shifted exponential decays described time-dependence of mean, surface and core temperatures close to perfect (mean R2 were 0.9990.001, 0.9960.004 and 0.9980.002, respectively). Mean time constants were ?mean?=?55.33.7 min, ?surface?=?41.42.9 min and ?core?=?76.87.1 min, mean relative time shifts were ?surface?=?0.070.02 and ?core?=?0.040.01. None of the constants correlated significantly with temperature differences between ambient and storage temperature. Conclusion Lumped capacitive model of heat transfer and shifted exponential decays represent simple analytical formulas to describe transient mean, surface and core temperatures of RBC during warm up, which might be a helpful tool in RBC temperature monitoring and quality control. Independence of constants on differences between ambient and storage temperature suggests validity of models for arbitrary storage and ambient temperatures. PMID:23469108

17. Transport in ultrathin gold films decorated with magnetic Gd atoms

Alemani, Micol; Helgren, Erik; Hugel, Addison; Hellman, Frances

2008-03-01

We have performed four-probe transport measurements of ultrathin Au films decorated with Gd ad-atoms. The samples were prepared by quench condensation, i.e., sequential evaporation on a cryogenically cooled substrate under UHV conditions while monitoring the film thickness and resistance. Electrically continuous Au films at thickness of about 2 mono-layers of material are grown on an amorphous Ge wetting layer. The quench condensation method provides a sensitive control on the sample growth process, allowing us to tune the morphological and electrical configuration of the system. The ultrathin gold films develop from an insulating to a metallic state as a function of film thickness. The temperature dependence of the Au conductivity for different thickness is studied. It evolves from hopping transport for the insulating films, to a ln T dependence for thicker films. For gold films in the insulating regime we found a decreasing resistance by adding Gd. This is in agreement with a decreasing tunneling barrier height between metallic atoms. The Gd magnetic moments are randomly oriented for isolated atoms. This magnetic disorder leads to scattering of the charge carriers and a reduced conductivity compared to nonmagnetic materials.

18. Cold magnetically trapped 2Dg scandium atoms. II. Scattering dynamics

Karman, Tijs; Groenenboom, Gerrit C.

2014-11-01

The binary collision dynamics of 2Dg ,3 /2 ground state scandium atoms is studied from first principles. We employ 30 coupled diabatic ab initio potentials in a coupled-channels study of the scattering dynamics of cold and ultracold scandium atoms in external magnetic fields. Due to the long-ranged magnetic dipolar interaction, the field dependence of the cross section does not follow the threshold laws derived by Volpi and Bohn [Phys. Rev. A 65, 052712 (2002), 10.1103/PhysRevA.65.052712]. In the field-free case, the near-threshold cross section is independent of the collision energy, and hence the cross section does not follow the well-established Wigner threshold laws. The observed threshold behavior is explained in the Born approximation. For energies above 1 ? K , inelastic collisions are driven by the anisotropic nonrelativistic electronic interaction. For energies below 100 ? K , the ratio of elastic-to-inelastic collisions is likely to be favorable for evaporative cooling. Both anisotropy in the long-range interaction and in the short-range potential contribute to large cross sections for inelastic collisions at higher energies and lead to a small ratio of elastic-to-inelastic collisions. This is in agreement with the large rates for Zeeman relaxation of submerged-shell atoms observed experimentally. The effect of the uncertainty in the ab initio potential is sampled by scaling the reduced mass and is found to have little influence on the conclusions drawn from this work.

19. Nonlocal electron transport in magnetized plasmas with arbitrary atomic number

SciTech Connect

Bennaceur-Doumaz, D.; Bendib, A.

2006-09-15

The numerical solution of the steady-state electron Fokker-Planck equation perturbed with respect to a global equilibrium is presented in magnetized plasmas with arbitrary atomic number Z. The magnetic field is assumed to be constant and the electron-electron collisions are described by the Landau collision operator. The solution is derived in the Fourier space and in the framework of the diffusive approximation which captures the spatial nonlocal effects. The transport coefficients are deduced and used to close a complete set of nonlocal electron fluid equations. This work improves the results of A. Bendib et al. [Phys. Plasmas 9, 1555 (2002)] and of A. V. Brantov et al. [Phys. Plasmas 10, 4633 (2003)] restricted to the local and nonlocal high-Z plasma approximations, respectively. The influence of the magnetic field on the nonlocal effects is discussed. We propose also accurate numerical fits of the relevant transport coefficients with respect to the collisionality parameter {lambda}{sub ei}/L and the atomic number Z, where L is the typical scale length and {lambda}{sub ei} is the electron-ion mean-free-path.

20. Nanoscale magnetic resonance imaging and magnetic sensing using atomic defects in diamond

Grinolds, Michael

Magnetic resonance imaging (MRI) has revolutionized modern medicine by providing non-invasive, chemically selective, three-dimensional imaging of living organisms. Industrial-scale MRI has the capability to image with millimeter-scale spatial resolution and has the sensitivity to detect as few as 1014 nuclear spins. Increasing spatial resolution to the atomic scale and sensitivity to the single-spin level would enable a wide array of applications most notably including imaging molecular structur. However, conventional MRI methods are already highly optimized, and further order-of-magnitude-scale improvements cannot be reasonably expected without employing fundamentally different technologies. This thesis presents an alternative approach to conventional MRI that pushes resolution and sensitivity to the individual atom and molecular level. The guiding principle for achieving multiple order-of-magnitude improvements is to miniaturize the key components of MRI: the detector and the source of magnetic-field gradients. By scaling down the physical size of these components to the nano- and atomic- scales, the signals from individual spins become measurable and resolvable. To miniature the detector, we employ an optically-active, paramagnetic atomic defect in diamond---a nitrogen-vacancy (NV) center---as our sensor. Owing to its optical readout, long coherence times, atomic-size, and room-temperature compatibility, NV centers in diamond have the capability to measure the magnetic fields from individual spins, provided the sensor can be placed sufficiently close to a target to be measured. This thesis describes the experimental realization of a microscope that can perform sensitive magnetometry experiments using a single NV center that magnetically images by spatially scanning the NV center within a few nanometers of magnetic targets. With this technique we are able to demonstrate the first room-temperature magnetic imaging of individual electron spins. For miniaturizing the magnetic-field gradient source, we use scanning nanoscale magnets, building off the success of those used in magnetic resonance force microscopy. By shrinking the magnetic field source to tens of nanometers in size, the magnitude of the magnetic field gradients can be increased by more than a factor of 105 compared to conventional MRI field gradients coils, which increases spatial resolution correspondingly. With these tips optimized for compatibility with NV-based measurements, we are able to achieve sub-nanometer resolution in MRI imaging.

1. Photon statistics and polarization correlations at telecommunications wavelengths from a warm atomic ensemble.

PubMed

Willis, R T; Becerra, F E; Orozco, L A; Rolston, S L

2011-07-18

We present measurements of the polarization correlation and photon statistics of photon pairs that emerge from a laser-pumped warm rubidium vapor cell. The photon pairs occur at 780 nm and 1367 nm and are polarization entangled. We measure the autocorrelation of each of the generated fields as well as the cross-correlation function, and observe a strong violation of the two-beam Cauchy-Schwartz inequality. We evaluate the performance of the system as source of heralded single photons at a telecommunication wavelength. We measure the heralded autocorrelation and see that coincidences are suppressed by a factor of ≈ 20 from a Poissonian source at a generation rate of 1500 s(-1), a heralding efficiency of 10%, and a narrow spectral width. PMID:21934825

2. Spin-polarized currents generated by magnetic Fe atomic chains.

PubMed

Lin, Zheng-Zhe; Chen, Xi

2014-06-13

Fe-based devices are widely used in spintronics because of high spin-polarization and magnetism. In this work, freestanding Fe atomic chains, the thinnest wires, were used to generate spin-polarized currents due to the spin-polarized energy bands. By ab initio calculations, the zigzag structure was found to be more stable than the wide-angle zigzag structure and had a higher ratio of spin-up and spin-down currents. By our theoretical prediction, Fe atomic chains have a sufficiently long thermal lifetime only at T??150 K, while C atomic chains are very stable even at T=1000 K. This means that the spintronic devices based on Fe chains could work only at low temperatures. A system constructed by a short Fe chain sandwiched between two graphene electrodes could be used as a spin-polarized current generator, while a C chain could not be used in this way. The present work may be instructive and meaningful to further practical applications based on recent technical developments on the preparation of metal atomic chains (Proc. Natl. Acad. Sci. USA 107 9055 (2010)). PMID:24849670

3. First principles calculation of the structural, electronic, and magnetic properties of Au-Pd atomic chains

Dave, Mudra R.; Sharma, A. C.

2015-06-01

The structural, electronic and magnetic properties of free standing Au-Pd bimetallic atomic chain is studied using ab-initio method. It is found that electronic and magnetic properties of chains depend on position of atoms and number of atoms. Spin polarization factor for different atomic configuration of atomic chain is calculated predicting a half metallic behavior. It suggests a total spin polarised transport in these chains.

4. DSMC simulations of polarized atomic beam sources including magnetic fields

Gaisser, M.; Nass, A.; Strher, H.

2014-01-01

In recent decades a lot of work has been done to understand and optimize the output of polarized atomic beam sources. However, there are many effects which prevent a complete analytic description of the system. Now, a DSMC ( Direct Simulation Monte Carlo) simulation based on OpenFOAM 1.7.1 using Birds algorithm is set up. So far, the simulated particles have been given spin and a generic utility to include arbitrary magnetic fields has been created. The equation of motion in every timestep is solved by a fourth order Runge-Kutta scheme. In this contribution, we describe promising first results of the simulations. Additionally a tool to measure the collision age has been created. Further effects to be included are recombination on the walls and spin exchange collisions. After that an algorithm will be included to optimize the output of the atomic beam source.

5. Microfabricated atomic vapor cell arrays for magnetic field measurements

SciTech Connect

Woetzel, S.; Schultze, V.; IJsselsteijn, R.; Schulz, T.; Anders, S.; Stolz, R.; Meyer, H.-G.

2011-03-15

We describe a method for charging atomic vapor cells with cesium and buffer gas. By this, it is possible to adjust the buffer gas pressure in the cells with good accuracy. Furthermore, we present a new design of microfabricated vapor cell arrays, which combine silicon wafer based microfabrication and ultrasonic machining to achieve the arrays of thermally separated cells with 50 mm{sup 3} volume. With cells fabricated in the outlined way, intrinsic magnetic field sensitivities down to 300 fT/Hz{sup 1/2} are reached.

6. Magnetic blackbody shift of hyperfine transitions for atomic clocks

SciTech Connect

Berengut, J. C.; Flambaum, V. V.; King-Lacroix, J.

2009-12-15

We derive an expression for the magnetic blackbody shift of hyperfine transitions such as the cesium primary reference transition which defines the second. The shift is found to be a complicated function of temperature, and has a T{sup 2} dependence only in the high-temperature limit. We also calculate the shift of ground-state p{sub 1/2} hyperfine transitions which have been proposed as new atomic clock transitions. In this case interaction with the p{sub 3/2} fine-structure multiplet may be the dominant effect.

7. Magnetic properties of manganese ferrite films grown at atomic scale

SciTech Connect

Zuo Xu; Yang, Aria; Yoon, Soack-Dae; Christodoulides, Joe A.; Harris, Vincent G.; Vittoria, Carmine

2005-05-15

Manganese ferrite is a partial inverse spinel which, when prepared by conventional growth techniques, has {approx}20% of the Mn{sup 2+} ions on the octahedral sublattice. Here we describe a layer-by-layer growth scheme at atomic scale by which the percentage of Mn{sup 2+} ions on the octahedral sublattice can be artificially controlled. Manganese ferrite films grown by this technique exhibits different degrees of cation inversion when grown on {l_brace}100{r_brace} and {l_brace}111{r_brace} MgO substrates. It was observed that saturation magnetization varied in a wide range of values depending on chemical composition and oxygen pressure. Although bulk manganese ferrite was low anisotropy magnetic material, uniaxial anisotropy was observed at room temperature in the films deposited on {l_brace}100{r_brace} MgO substrates, and its magnitude and direction sensitively depended on chemical composition and oxygen pressure during deposition.

8. Tracing Magnetic Fields by Atomic Alignment in Extended Radiation Fields

Zhang, Heshou; Yan, Huirong; Dong, Le

2015-05-01

9. Magnetic induction measurements using an all-optical {sup 87}Rb atomic magnetometer

SciTech Connect

Wickenbrock, Arne; Tricot, Franois; Renzoni, Ferruccio

2013-12-09

In this work we propose, and experimentally demonstrate, the use of a self-oscillating all-optical atomic magnetometer for magnetic induction measurements. Given the potential for miniaturization of atomic magnetometers, and their extreme sensitivity, the present work shows that atomic magnetometers may play a key role in the development of instrumentation for magnetic induction tomography.

10. Precession Control on Precipitation in the Western Pacific Warm Pool Inferred from Environmental Magnetism

Yamazaki, T.

2014-12-01

The Western Pacific Warm Pool (WPWP) has highest water temperature in the global ocean, and its spatiotemporal variations have significant impacts on large-scale atmospheric circulation and global hydrology. An environmental magnetic study was conducted on sediment cores of late Pleistocene age taken from the West Caroline Basin (WCB) offshore northern New Guinea in order to constrain hydrological variability over the WPWP on orbital timescales. Magnetite dominates magnetic mineral assemblages of the sediments. This is evidenced by that IRM acquisition curves are mostly explained by a low-coercivity component, and that the Verwey transition was obvious in low-temperature measurements. Existence of the sharp central ridges on FORC diagrams and TEM images indicate the occurrence of biogenic magnetite. Compared with pelagic sediments from other regions, however, FORC diagrams show a larger contribution of an interacting PSD and MD component, and the ratios of ARM susceptibility to SIRM (kARM/SIRM) are lower, which suggests a larger proportion of the terrigenous component. This is probably due to a large terrigenous sediment input from nearby land, New Guinea, induced by high precipitation in the intertropical convergence zone. Magnetic susceptibility (k) and kARM/SIRM well correlate with northern-hemisphere summer insolation. Maxima in k and minima in kARM/SIRM correspond to insolation minima, which suggests a larger terrigenous input caused by higher precipitation at these times. Interestingly, in the western part of WCB, k variations are dominated by the eccentricity periodicity and mimic ?18O curves, but the precession periodicity prevails in kARM/SIRM. These cores were taken at depths close to the CCD, and thus the k variations cannot be explained by dilution with carbonates. Sedimentation influenced by global sea-level changes may control the k variations; this part of the basin is adjacent to a wider continental shelf compared with the eastern part of WCB.

11. Cold and warm atomic gas around the Perseus molecular cloud. I. Basic properties

SciTech Connect

Stanimirović, Snežana; Murray, Claire E.; Miller, Jesse; Lee, Min-Young

2014-10-01

Using the Arecibo Observatory, we have obtained neutral hydrogen (HI) absorption and emission spectral pairs in the direction of 26 background radio continuum sources in the vicinity of the Perseus molecular cloud. Strong absorption lines were detected in all cases, allowing us to estimate spin temperature (T{sub s} ) and optical depth for 107 individual Gaussian components along these lines of sight. Basic properties of individual H I clouds (spin temperature, optical depth, and the column density of the cold and warm neutral medium (CNM and WNM), respectively) in and around Perseus are very similar to those found for random interstellar lines of sight sampled by the Millennium H I survey. This suggests that the neutral gas found in and around molecular clouds is not atypical. However, lines of sight in the vicinity of Perseus have, on average, a higher total H I column density and the CNM fraction, suggesting an enhanced amount of cold H I relative to an average interstellar field. Our estimated optical depth and spin temperature are in stark contrast with the recent attempt at using Planck data to estimate properties of the optically thick H I. Only ∼15% of lines of sight in our study have a column density weighted average spin temperature lower than 50 K, in comparison with ≳ 85% of Planck's sky coverage. The observed CNM fraction is inversely proportional to the optical depth weighted average spin temperature, in excellent agreement with the recent numerical simulations by Kim et al. While the CNM fraction is, on average, higher around Perseus relative to a random interstellar field, it is generally low, between 10%-50%. This suggests that extended WNM envelopes around molecular clouds and/or significant mixing of CNM and WNM throughout molecular clouds are present and should be considered in the models of molecule and star formation. Our detailed comparison of H I absorption with CO emission spectra shows that only 3 of the 26 directions are clear candidates for probing the CO-dark gas as they have N(H I)>10{sup 21} cm{sup –2} yet no detectable CO emission.

12. Magnetic conveyor belt transport of ultracold atoms to a superconducting atomchip

Minniberger, Stefan; Diorico, Fritz; Haslinger, Stefan; Hufnagel, Christoph; Novotny, Christian; Lippok, Nils; Majer, Johannes; Koller, Christian; Schneider, Stephan; Schmiedmayer, Jrg

2014-09-01

We report the realization of a robust magnetic transport scheme to bring >3 108 ultracold 87Rb atoms into a cryostat. The sequence starts with standard laser cooling and trapping of 87Rb atoms, transporting first horizontally and then vertically through the radiation shields into a cryostat by a series of normal- and superconducting magnetic coils. Loading the atoms in a superconducting microtrap paves the way for studying the interaction of ultracold atoms with superconducting surfaces and quantum devices requiring cryogenic temperatures.

13. An average atom code for warm matter: application to aluminum and uranium.

PubMed

Pnicaud, Michel

2009-03-01

In astrophysics and in other sciences there is sometimes a need for information about the properties of matter, particularly equations of state, in extreme conditions of pressure and temperature. Global equation of state models, which represent solid, fluid and plasma states, typically consist of three parts: the cold curve, the ion-thermal contribution and the electron-thermal contribution. For the calculation of the latest part we present here an average atom embedded in a jellium code. We employ Liberman's relativistic and quantum model of matter which is a significant advance in complexity beyond the commonly used Thomas-Fermi model. We have applied specific algorithms to deal with the highly oscillatory nature of the free wavefunctions at high temperatures and to capture resonances which form in the continuum when bound states are destroyed by pressure ionization. Also we use massive parallel computing to treat the huge number of free wavefunctions at high temperatures (up to 10(9)K). Densities of states of resonant states are shown for uranium. With our code, which we have called Paradisio, we obtain tables of electron-thermal entropies from which free energies and pressures are derived. Our results are compared with those calculated in the Thomas-Fermi approximation and with available experiments. In aluminum, with our quantum code, a shell structure appears on the Hugoniot and a first-order metallic-nonmetallic transition is created at low densities and temperatures. PMID:21817395

14. Magnetism of Mn single atom and dimer on Co(0001) hcp surface: Density functional calculations

Molina-Duarte, J. J.; Delgado-Nieblas, F. C.; Flix-Medina, R. E.; Leyva-Lucero, M. A.; Meza-Aguilar, S.; Demangeat, C.

2015-12-01

Magnetism of Mn single atom and dimer on Co(0001) hcp surface is studied on the basis of density functional theory using Quantum Espresso code. The most stable geometry takes place when Mn is adsorbed in the most highly coordinated sites. Mn single atom couples ferromagnetically to the Co atoms and shows a high magnetic moment of 4.53 ?B. Mn dimer also couples ferromagnetically to the Co atoms, shows a mean atomic magnetic moment of 4.45 ?B, and increases its interatomic distance to minimize its energy.

15. Magnetic Waveguide for Atom Interferometry and Inertial Navigation Applications

Horne, Robert; Sackett, Charles

2014-05-01

Atom interferometry using Bose-Einstein condensates has potential applications in inertial navigation. We present recent work on the development of a new magnetic waveguide specifically designed for these inertial navigation measurements. The waveguide is implemented using a modified Time Orbiting Potential (TOP) configuration that will allow support against gravity and provide a cylindrically symmetric, harmonic trapping potential for our 87Rb condensate. Based on simulations, the trap will be continuously adjustable, providing trapping frequencies in the horizontal plane from 1 Hz to 100 Hz. This will allow the implementation of a scalable gyroscope and an accelerometer using the same device. Additionally, the trap is continuously deformable from a harmonic potential to a ring trap. Trap characterization and additional measurement results will also be presented. Supported by the NSF.

16. Determination of the line shapes of atomic nitrogen resonance lines by magnetic scans

NASA Technical Reports Server (NTRS)

Lawrence, G. M.; Stone, E. J.; Kley, D.

1976-01-01

A technique is given for calibrating an atomic nitrogen resonance lamp for use in determining column densities of atoms in specific states. A discharge lamp emitting the NI multiplets at 1200 A and 1493 A is studied by obtaining absorption by atoms in a magnetic field (0-2.5 T). This magnetic scanning technique enables the determination of the absorbing atom column density, and an empirical curve of growth is obtained because the atomic f-value is known. Thus, the calibrated lamp can be used in the determination of atomic column densities.

17. Mapping magnetism with atomic resolution using aberrated electron probes

Idrobo, Juan; Rusz, Ján; McGuire, Michael A.; Symons, Christopher T.; Vatsavai, Ranga Raju; Lupini, Andrew R.

2015-03-01

In this talk, we report a direct experimental real-space mapping of magnetic circular dichroism with atomic resolution in aberration-corrected scanning transmission electron microscopy (STEM). Using an aberrated electron probe with customized phase distribution, we reveal with electron energy-loss (EEL) spectroscopy the checkerboard antiferromagnetic ordering of Mn moments in LaMnAsO by observing a dichroic signal in the Mn L-edge. The aberrated probes allow the collection of EEL spectra using the transmitted beam, which results in a magnetic circular dichroic signal with intrinsically larger signal-to-noise ratios than those obtained via nanodiffraction techniques (where most of the transmitted electrons are discarded). The novel experimental setup presented here, which can easily be implemented in aberration-corrected STEM, opens new paths for probing dichroic signals in materials with unprecedented spatial resolution. This research was supported by DOE SUFD MSED, by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the US DOE, and by the Swedish Research Council and Swedish National Infrastructure for Computing (NSC center)

18. Atomic spin resonance in a rubidium beam obliquely incident to a transmission magnetic grating

Hatakeyama, A.; Goto, K.

2016-03-01

We studied atomic spin resonance induced by atomic motion in a spatially periodic magnetostatic field. A rubidium atomic beam, with a velocity of about 400 m s‑1, was obliquely incident to a transmission magnetic grating that produced a spatially periodic magnetic field. The magnetic grating was formed by a magnetic thin film on a polyimide substrate that had multiple slits at 150 μm intervals. The atoms experienced field oscillation, depending on their velocity and the field period when passing through the grating, and underwent magnetic resonance. Resonance spectra obtained with a perpendicular magnetization film were in clear contrast to ones obtained with an in-plane magnetization film. The former exhibited resonance peaks at odd multiples of the frequency, determined by the velocity over the period, while the latter had dips at the same frequencies.

19. Magnetic levitation for effective loading of cold cesium atoms in a crossed dipole trap

Li, Yuqing; Feng, Guosheng; Xu, Rundong; Wang, Xiaofeng; Wu, Jizhou; Chen, Gang; Dai, Xingcan; Ma, Jie; Xiao, Liantuan; Jia, Suotang

2015-05-01

20. Atomic site sensitivity of the energy loss magnetic chiral dichroic spectra of complex oxides

SciTech Connect

Calmels, L.; Rusz, J.

2011-04-01

The quantitative analysis of magnetic oxide core level spectra can become complicated when the magnetic atoms are located at several nonequivalent atomic sites in the crystal. This is, for instance, the case for Fe atoms in magnetite, which are located in tetrahedral and octahedral atomic sites; in this case, the x-ray magnetic circular dichroic (XMCD) spectra recorded at the L{sub 2,3} edge of Fe contain contributions from the different nonequivalent atomic sites, which unfortunately cannot be separated. Energy loss magnetic chiral dichroic (EMCD) spectra are the transmission electron microscope analogies of the XMCD spectra. One of the important differences between these two techniques of magnetic analysis is that EMCD uses a fast electron beam instead of polarized light. The fast electrons behave like Bloch states in the sample, and the fine structure of the EMCD spectra is strongly influenced by channeling and dynamical diffraction effects. These effects can be adjusted by changing the experimental configuration. We use theoretical calculations, which include dynamical diffraction effects and in which electronic transitions are treated in the atomic multiplet formalism, to show that the relative weight of the Fe atoms in different nonequivalent atomic sites can be changed by a proper choice of the position of the detector and of the magnetite sample orientation and thickness. We conclude that EMCD spectra could be used to isolate the magnetic contribution of atoms in each of the nonequivalent atomic sites, which would not be possible with XMCD techniques.

1. Effect of magnetism and atomic order on static atomic displacements in the Invar alloy Fe-27 at.% Pt

Sax, C. R.; Schönfeld, B.; Ruban, A. V.

2015-08-01

Fe-27 at.% Pt was aged at 1123 K and quenched to room temperature (RT) to set up a state of thermal equilibrium. The local atomic arrangement was studied by diffuse x-ray scattering above (at 427 K) and below (at RT) the Curie temperature as well as at RT under a saturating magnetic field. The separated short-range order scattering remained unchanged for all three states, with maxima at 100 positions. Effective pair interaction parameters determined by the inverse Monte Carlo method gave an order-disorder transition temperature of about 1088 K, close to direct experimental findings. The species-dependent static atomic displacements for the first two shells show large differences, with a strong increase in magnitude from the state at 427 K over RT to the state under saturating magnetic field. This outcome is in agreement with an increase in atomic volume of Fe with increasing local magnetic moment. Electronic-structure calculations closely reproduce the values for the static atomic displacements in the ferromagnetic state, and predict their dependence on the atomic configuration. They also reveal a strong dependence of the magnetic exchange interactions in Fe-Pt on the atomic configuration state and lattice parameter. In particular, the increase of the Curie temperature in a random state relative to that in the ordered one is demonstrated to be related to the corresponding change of the magnetic exchange interactions due to the different local atomic chemical environment. There exists a similar strong concentration dependence of the chemical interactions as in the case of magnetic exchange interactions. Theoretical effective interactions for Fe-27 at.% Pt alloy are in good agreement with experimental results, and they also reproduce well the L1 2-A1 transition temperature.

2. Apparatus for trapping and thermal detection of atomic hydrogen in high magnetic fields at low temperatures

NASA Technical Reports Server (NTRS)

Woollam, J. A.

1980-01-01

An apparatus is described in which hydrogen atoms were trapped at temperatures down to 1.1 K in the 11 T field of a large volume superconducting magnet. A high sensitivity thermal detector was used to study trapping and recombination of atoms on the detector surface. The apparatus permits the application of extremely high steady state magnetic fields to study the potential effects of electron spin polarization on the stabilization of hydrogen atoms.

3. Magnetic excitations of rare earth atoms and clusters on metallic surfaces.

PubMed

Schuh, Tobias; Miyamachi, Toshio; Gerstl, Stefan; Geilhufe, Matthias; Hoffmann, Martin; Ostanin, Sergey; Hergert, Wolfram; Ernst, Arthur; Wulfhekel, Wulf

2012-09-12

Magnetic anisotropy and magnetization dynamics of rare earth Gd atoms and dimers on Pt(111) and Cu(111) were investigated with inelastic tunneling spectroscopy. The spin excitation spectra reveal that giant magnetic anisotropies and lifetimes of the excited states of Gd are nearly independent of the supporting surfaces and the cluster size. In combination with theoretical calculations, we argue that the observed features are caused by strongly localized character of 4f electrons in Gd atoms and clusters. PMID:22906055

4. Engineering the magnetic anisotropy of atomic-scale nanostructure under electric field

Zhu, Wanjiao; Ding, Hang-Chen; Tong, Wen-Yi; Gong, Shi-Jing; Wan, Xiangang; Duan, Chun-Gang

2015-02-01

Atomic-scale magnetic nanostructures are promising candidates for future information processing devices. Utilizing external electric field to manipulate their magnetic properties is an especially thrilling project. Here, by carefully identifying the different contributions of each atomic orbital to the magnetic anisotropy energy (MAE) of the ferromagnetic metal films, we argue that it is possible to engineer both the MAE and the magnetic response to the electric field of atomic-scale magnetic nanostructures. Taking the iron monolayer as a matrix, we propose several interesting iron nanostructures with dramatically different magnetic properties. Such nanostructures could exhibit a strong magnetoelectric effect. Our work may open new avenues to the artificial design of electrically controlled magnetic devices.

5. Effects of warm temper rolling on microstructure, texture and magnetic properties of strip-casting 6.5 wt% Si electrical steel

Li, Hao-Ze; Liu, Hai-Tao; Liu, Yi; Liu, Zhen-Yu; Cao, Guang-Ming; Luo, Zhong-Han; Zhang, Feng-Quan; Chen, Sheng-Lin; Lyu, Li; Wang, Guo-Dong

2014-12-01

6.5 wt% Si electrical steel thin sheets were produced by a processing route including strip casting, hot rolling, warm rolling, intermediate annealing, warm temper rolling and final annealing, in which the warm temper rolling reduction varied from 2.7% to 14.4%. A detailed study of the microstructural and textural evolutions through the whole processing route was carried out by optical microscopy, X-ray diffraction and electron backscattered diffraction analysis. The findings revealed that the final recrystallization microstructure, texture and magnetic properties relied heavily on the warm temper rolling reduction. As the warm temper rolling reduction increased from 2.7% to 14.4%, the finally recrystallized microstructures were more homogeneous and the average grain size was decreased. At the warm temper rolling reduction lower than 7.0%, the occurrence of the exaggeratedly large annealing grains which dominated the whole sheet thickness resulted in strong <001>//ND fiber, parallel ?-fiber, <111>//ND fiber and many other strong hard-magnetization texture components. By contrast, at the warm temper rolling reduction higher than 7.0%, the recrystallization textures were characterized by weak <001>//ND fiber, parallel ?-fiber, <111>//ND texture, together with fewer and weak hard-magnetization texture components. The mechanism responsible for the finally microstructural and textural changes was explained by strain induced boundary migration. As warm temper rolling reduction increased, the magnetic properties at high frequency were gradually improved due to smaller grain sizes and more desirable textures. The highest magnetic inductions of 1.383 T (B8), 1.484 T (B25) and 1.571 T (B50) in combination with the lowest iron losses at high frequencies of 19.11 W/Kg (W10/400) and 3.824 W/Kg (W2/1000) were obtained at 14.4% warm temper rolling reduction under the applied condition.

6. Origin of Perpendicular Magnetic Anisotropy and Large Orbital Moment in Fe Atoms on MgO

Baumann, S.; Donati, F.; Stepanow, S.; Rusponi, S.; Paul, W.; Gangopadhyay, S.; Rau, I. G.; Pacchioni, G. E.; Gragnaniello, L.; Pivetta, M.; Dreiser, J.; Piamonteze, C.; Lutz, C. P.; Macfarlane, R. M.; Jones, B. A.; Gambardella, P.; Heinrich, A. J.; Brune, H.

2015-12-01

We report on the magnetic properties of individual Fe atoms deposited on MgO(100) thin films probed by x-ray magnetic circular dichroism and scanning tunneling spectroscopy. We show that the Fe atoms have strong perpendicular magnetic anisotropy with a zero-field splitting of 14.0 ±0.3 meV /atom . This is a factor of 10 larger than the interface anisotropy of epitaxial Fe layers on MgO and the largest value reported for Fe atoms adsorbed on surfaces. The interplay between the ligand field at the O adsorption sites and spin-orbit coupling is analyzed by density functional theory and multiplet calculations, providing a comprehensive model of the magnetic properties of Fe atoms in a low-symmetry bonding environment.

7. Origin of Perpendicular Magnetic Anisotropy and Large Orbital Moment in Fe Atoms on MgO.

PubMed

Baumann, S; Donati, F; Stepanow, S; Rusponi, S; Paul, W; Gangopadhyay, S; Rau, I G; Pacchioni, G E; Gragnaniello, L; Pivetta, M; Dreiser, J; Piamonteze, C; Lutz, C P; Macfarlane, R M; Jones, B A; Gambardella, P; Heinrich, A J; Brune, H

2015-12-01

We report on the magnetic properties of individual Fe atoms deposited on MgO(100) thin films probed by x-ray magnetic circular dichroism and scanning tunneling spectroscopy. We show that the Fe atoms have strong perpendicular magnetic anisotropy with a zero-field splitting of 14.00.3??meV/atom. This is a factor of 10 larger than the interface anisotropy of epitaxial Fe layers on MgO and the largest value reported for Fe atoms adsorbed on surfaces. The interplay between the ligand field at the O adsorption sites and spin-orbit coupling is analyzed by density functional theory and multiplet calculations, providing a comprehensive model of the magnetic properties of Fe atoms in a low-symmetry bonding environment. PMID:26684139

8. Nanofiber-based atom trap created by combining fictitious and real magnetic fields

Schneeweiss, Philipp; Le Kien, Fam; Rauschenbeutel, Arno

2014-01-01

We propose a trap for cold neutral atoms using a fictitious magnetic field induced by a nanofiber-guided light field in conjunction with an external magnetic bias field. In close analogy to magnetic side-guide wire traps realized with current-carrying wires, a trapping potential can be formed when applying a homogeneous magnetic bias field perpendicular to the fiber axis. We discuss this scheme in detail for laser-cooled cesium atoms and find trap depths and trap frequencies comparable to the two-color nanofiber-based trapping scheme but with one order of magnitude lower power of the trapping laser field. Moreover, the proposed scheme allows one to bring the atoms closer to the nanofiber surface, thereby enabling efficient optical interfacing of the atoms with additional light fields. Specifically, optical depths per atom, σ0/Aeff, of more than 0.4 are predicted, making this system eligible for nanofiber-based nonlinear and quantum optics experiments.

9. Magnetic coupling of laser-cooled atoms to a micro-resonator

Geraci, Andrew; Wang, Ying-Ju; Eardley, Matthew; Moreland, John; Kitching, John

2009-05-01

The direct coupling of the spin-degrees of freedom of an atomic vapor to the vibrational motion of a magnetic cantilever tip has recently been demonstrated [1], and prospects for coupling a BEC on an atom-chip to a nano- mechanical resonator have been recently discussed [2]. Possible applications include chip-scale atomic devices, in which localized interactions with magnetic cantilever tips selectively influence or probe atomic spins. As a next step towards the realization of a strongly coupled ultra-cold atom- resonator system, we have constructed an apparatus to study the direct coupling between the spins of trapped laser-cooled Rb atoms and a magnetic tip on a micro-cantilever. The atoms will be loaded into a magnetic trap formed by the cantilever tip and external magnetic fields. The cantilever will be driven capacitively at its resonance frequency, resulting in a coherent precession of the trapped atomic spins with a matching Larmor frequency. Prospects for measuring the back-action of the ensemble of atomic spins on a cantilever beam will also be discussed. [1] Y.-J. Wang,M. Eardley, S. Knappe, J. Moreland, L. Hollberg, and J. Kitching, PRL 97, 227602 (2006). [2] P. Treutlein,D. Hunger, S. Camerer, T. W. Hansch, and J. Reichel, PRL 99, 140403 (2007).

10. Embedding Transition-Metal Atoms in Graphene: Structure, Bonding, and Magnetism

Krasheninnikov, A. V.; Lehtinen, P. O.; Foster, A. S.; Pyykk, P.; Nieminen, R. M.

2009-03-01

We present a density-functional-theory study of transition-metal atoms (Sc-Zn, Pt, and Au) embedded in single and double vacancies (SV and DV) in a graphene sheet. We show that for most metals, the bonding is strong and the metal-vacancy complexes exhibit interesting magnetic behavior. In particular, an Fe atom on a SV is not magnetic, while the Fe@DV complex has a high magnetic moment. Surprisingly, Au and Cu atoms at SV are magnetic. Both bond strengths and magnetic moments can be understood within a simple local-orbital picture, involving carbon sp2 hybrids and the metal spd orbitals. We further calculate the barriers for impurity-atom migration, and they agree well with available experimental data. We discuss the experimental realization of such systems in the context of spintronics and nanocatalysis.

11. Atoms in Strong Magnetic Fields. Quantum Mechanical Treatment and Applications in Astrophysics and Quantum Chaos

Ruder, Hanns; Wunner, Günter; Herold, Heinz; Geyer, Florian

This book serves both students and researchers. It gives a clear and accessible introduction to quantum mechanical methods used to calculate properties of atoms exposed to strong magnetic fields in both laboratory and stellar environments. The results of the detailed calculations are listed in tables, making it a useful handbook for astrophysicists and atomic physicists alike. The emphasis is on hydrogen and helium and their isoelectronic sequences. Important applications are highlighted: the interpretation of the spectra of strongly magnetic white dwarf stars, and the prominent role of atoms in strong magnetic fields in studies of quantum chaos.

12. Design of a millimetre-scale magnetic surface trap for cold atoms

Trypogeorgos, D.; Albright, S. D.; Beesley, D.; Foot, C. J.

2014-04-01

We study a novel millimetre-scale magnetic trap for ultracold atoms, in which the current carrying conductors can be situated outside the vacuum region, a few mm away from the atoms. This design generates a magnetic field gradient in excess of 1000 G cm-1 at a distance of 2 mm from the conductors. We perform electromagnetic and thermo-mechanical characterization using finite element methods. The predicted behaviour has been verified by electrical and thermal measurements on a prototype, but has not been implemented on an apparatus with cold atoms. Operating this trap at the highest gradient allows rapid evaporative cooling comparable to that achieved by atom chips.

13. Magnetic-field-driven localization of light in a cold-atom gas.

PubMed

Skipetrov, S E; Sokolov, I M

2015-02-01

We discover a transition from extended to localized quasimodes for light in a gas of immobile two-level atoms in a magnetic field. The transition takes place either upon increasing the number density of atoms in a strong field or upon increasing the field at a high enough density. It has many characteristic features of a disorder-driven (Anderson) transition but is strongly influenced by near-field interactions between atoms and the anisotropy of the atomic medium induced by the magnetic field. PMID:25699442

14. Asymmetrical two-dimensional magnetic lattices for ultracold atoms

SciTech Connect

Abdelrahman, A.; Vasiliev, M.; Alameh, K.; Hannaford, P.

2010-07-15

A simple method for implementing an asymmetrical two-dimensional magnetic lattice is proposed. The asymmetrical two-dimensional magnetic lattice is created by periodically distributing nonzero magnetic minima across the surface of a magnetic thin film, where the magnetic patterns are formed by milling nxn square holes on the surface of the film. The method is proposed for trapping and confining quantum degenerate gases, such as Bose-Einstein condensates and ultracold Fermi gases, prepared in low-magnetic-field-seeking states. Analytical expressions and numerical simulation results of the magnetic local minima are shown where we analyze the effect of changing the magnetic lattice parameters, such as the separation of the holes, the hole size, and external bias magnetic fields, to maintain and locate the nonzero local minima at a suitable distance above the film surface to avoid the effect of Majorana spin flips and the Casimir-Polder potential.

15. Association of atoms into universal dimers using an oscillating magnetic field.

PubMed

Langmack, Christian; Smith, D Hudson; Braaten, Eric

2015-03-13

In a system of ultracold atoms near a Feshbach resonance, pairs of atoms can be associated into universal dimers by an oscillating magnetic field with a frequency near that determined by the dimer binding energy. We present a simple expression for the transition rate that takes into account many-body effects through a transition matrix element of the contact. In a thermal gas, the width of the peak in the transition rate as a function of the frequency is determined by the temperature. In a dilute Bose-Einstein condensate of atoms, the width is determined by the inelastic scattering rates of a dimer with zero-energy atoms. Near an atom-dimer resonance, there is a dramatic increase in the width from inelastic atom-dimer scattering and from atom-atom-dimer recombination. The recombination contribution provides a signature for universal tetramers that are Efimov states consisting of two atoms and a dimer. PMID:25815927

16. Designing and building a permanent magnet Zeeman slower for calcium atoms using a 3D printer

Parsagian, Alexandria; Kleinert, Michaela

2015-10-01

We present the design of a Zeeman slower for calcium atoms using permanent magnets instead of more traditional electromagnets and the novel technique of 3D printing to create a very robust and flexible structure for these magnets. Zeeman slowers are ideal tools to slow atoms from several hundreds of meters per second to just a few tens of meters per second. These slower atoms can then easily be trapped in a magneto-optical trap, making Zeeman slowers a very valuable tool in many cold atom labs. The use of permanent magnets and 3D printing results in a highly stable and robust slower that is suitable for undergraduate laboratories. In our design, we arranged 28 magnet pairs, 2.0 cm apart along the axis of the slower and at varying radial distances from the axis. We determined the radial position of the magnets by simulating the combined field of all magnet pairs using Mathematica and comparing it to the ideal theoretical field for a Zeeman slower. Finally, we designed a stable, robust, compact, and easy-to-align mounting structure for the magnets in Google Sketchup, which we then printed using a commercially available 3D printer by Solidoodle. The resulting magnetic field is well suited to slow calcium atoms from the 770 m/s rms velocity at a temperature of 950 K, down to the capture velocity of the magneto-optical trap.

17. Magnetic induction tomography using an all-optical ^87Rb atomic magnetometer

Wickenbrock, Arne; Jurgilas, Sarunas; Dow, Albert; Marmugi, Luca; Renzoni, Ferruccio

2014-11-01

We demonstrate Magnetic Induction Tomography (MIT) with an all-optical atomic magnetometer. Our instrument creates a conductivity map of conductive objects. Both shape and size of the imaged samples compare very well with the actual shape and size. Given the potential of all-optical atomic magnetometers for miniaturization and extreme sensitivity, the proof-of-principle presented here opens up promising avenues in the development of instrumentation for magnetic induction tomography.

18. Magnetic Resonance Study of Atomic Excitations in Solid Molecular Hydrogens

Collins, Gilbert Wilson, III

We study unpaired hydrogen (H,D,T) atoms in a solid molecular hydrogen lattice using EPR at 9.37 GHz. The unpaired atoms are produced by the disintegration of the triton. By studying the evolution of the EPR spectrum at fixed temperature, we are able to quantify the absolute number of atoms, the linewidth, and the spin lattice relaxation time from 1.2 K to 10 K. The observed time dependence of the atom concentration fits a tanh function plus a small linear term, but there appears to be some structure for different samples. The number of atoms increases with decreasing temperature and we have observed concentrations over 1000 ppm. The linewidth is seen to be a linear function of the atom density and nuclear spin density as predicted by Drabold and Fedders. The nuclear spin contribution to the linewidth agrees quantitatively with theory and gives insight as to the location of the various atoms. The contribution to the linewidth from the unpaired atoms indicates that there may be many more atoms than those in the narrow resonance region. The electron spin lattice relaxation T_1 is measured by a saturation recovery method and is seen to increase with increasing temperature up to 8 K. T_1 is seen to depend on the ortho concentration and linearly on the atom concentration. A diffusion coefficient is obtained from both the relaxation times and the recombination coefficient. The two diffusion coefficients differ by up to 5 orders of magnitude for T_2. The diffusion is very insensitive to the temperature characteristic of a quantum diffusion regime. Quantum tunneling has been observed for H and D atoms in HD but there is no isotope effect for D and T atoms in D-T. Finally, we have observed spontaneous and stimulated depopulation of the atomic excitations giving rise to large energy releases as studied by the sample thermometer. We characterize this phenomenon by doing a coincidence detection of the atom concentration, the thermal conductivity and NMR on the nuclei of the molecular lattice.

19. The electrically detected magnetic resonance microscope: combining conductive atomic force microscopy with electrically detected magnetic resonance.

PubMed

Klein, Konrad; Hauer, Benedikt; Stoib, Benedikt; Trautwein, Markus; Matich, Sonja; Huebl, Hans; Astakhov, Oleksandr; Finger, Friedhelm; Bittl, Robert; Stutzmann, Martin; Brandt, Martin S

2013-10-01

We present the design and implementation of a scanning probe microscope, which combines electrically detected magnetic resonance (EDMR) and (photo-)conductive atomic force microscopy ((p)cAFM). The integration of a 3-loop 2-gap X-band microwave resonator into an AFM allows the use of conductive AFM tips as a movable contact for EDMR experiments. The optical readout of the AFM cantilever is based on an infrared laser to avoid disturbances of current measurements by absorption of straylight of the detection laser. Using amorphous silicon thin film samples with varying defect densities, the capability to detect a spatial EDMR contrast is demonstrated. Resonant current changes as low as 20 fA can be detected, allowing the method to realize a spin sensitivity of 810(6)spins/?Hz at room temperature. PMID:24182133

20. The Saga of Light-Matter Interaction and Magneto-optical Effects Applications to Atomic Magnetometry, Laser-cooled Atoms, Atomic Clocks, Geomagnetism, and Plant Bio-magnetism

Corsini, Eric P.

The quest to expand the limited sensorial domain, in particular to bridge the inability to gauge magnetic fields near and far, has driven the fabrication of remedial tools. The interaction of ferromagnetic material with a magnetic field had been the only available technique to gauge that field for several millennium. The advent of electricity and associated classical phenomena captured in the four Maxwell equations, were a step forward. In the early 1900s, the model of quantum mechanics provided a two-way leap forward. One came from the newly understood interaction of light and matter, and more specifically the three-way coupling of photons, atoms' angular momenta, and magnetic field, which are the foundations of atomic magnetometry. The other came from magnetically sensitive quantum effects in a fabricated energy-ladder form of matter cooled to a temperature below that of the energy steps; these quantum effects gave rise to the superconducting quantum interference device (SQUID). Research using atomic magnetometers and SQUIDs has resulted in thousands of publications, text books, and conferences. The current status in each field is well described in Refs. [48,49,38,42] and all references therein. In this work we develop and investigate techniques and applications pertaining to atomic magnetometry. [Full text: eric.corsini gmail.com].

1. Atomic Stern-Gerlach interferences with time-dependent magnetic fields

SciTech Connect

Nic Chormaic, S.; Miniatura, C.; Gorceix, O.; Viaris de Lesegno, B.; Robert, J.; Feron, S.; Lorent, V.; Reinhardt, J.; Baudon, J.; Rubin, K. )

1994-01-03

In atomic Stern-Gerlach (polarization) interferometry with time-dependent magnetic fields both the spatial and temporal parts of the atomic phase are generally affected. This leads to a total energy shift and to an inelastic momentum transfer. Some of the related effects are studied using a beam of metastable hydrogen atoms. In particular the scalar Aharonov-Bohm effect and its nondispersivity are considered, in addition to other phase shift effects occurring where the field gradient differs from zero.

2. Decoherence-governed magnetic-moment dynamics of supported atomic objects

Gauyacq, Jean-Pierre; Lorente, Nicols

2015-11-01

Due to the quantum evolution of molecular magnetic moments, the magnetic state of nanomagnets can suffer spontaneous changes. This process can be completely quenched by environment-induced decoherence. However, we show that for typical small supported atomic objects, the substrate-induced decoherence does change the magnetic-moment evolution but does not quell it. To be specific and to compare with experiment, we analyze the spontaneous switching between two equivalent magnetization states of atomic structures formed by Fe on Cu2N/Cu (1 0 0), measured by Loth et al (2012 Science 335 1969). Due to the substrate-induced decoherence, the Rabi oscillations proper to quantum tunneling between magnetic states are replaced by an irreversible decay of long characteristic times leading to the observed stochastic magnetization switching. We show that the corresponding switching rates are small, rapidly decreasing with systems size, with a 1/T thermal behavior and in good agreement with experiments. Quantum tunneling is recovered as the switching mechanism at extremely low temperatures below the ?K range for a six-Fe-atom system and exponentially lower for larger atomic systems. The unexpected conclusion of this work is that experiments could detect the switching of these supported atomic systems because their magnetization evolution is somewhere between complete decoherence-induced stability and unobservably fast quantum-tunneling switching.

3. Detection of magnetic-labeled antibody specific recognition events by combined atomic force and magnetic force microscopy

Hong, Xia; Liu, Yanmei; Li, Jun; Guo, Wei; Bai, Yubai

2009-09-01

Atomic force (AFM) and magnetic force microscopy (MFM) were developed to detect biomolecular specific interaction. Goat anti-mouse immunoglobulin (anti-IgG) was covalently attached onto gold substrate modified by a self-assembly monolayer of thioctic acid via 1-ethyl-3-[3-(dimethylamino) propyl] carbodiimide (EDC) activation. Magnetic-labeled IgG then specifically adsorbed onto anti-IgG surface. The morphological variation was identified by AFM. MFM was proved to be a fine assistant tool to distinguish the immunorecognized nanocomposites from the impurities by detection of the magnetic signal from magnetic-labeled IgG. It would enhance the understanding of biomolecular recognition process.

4. Atomic structure and magnetic properties of Fe1-xCox alloys

SciTech Connect

Nguyen, Manh Cuong; Zhao, Xin; Ji, Min; Wang, Cai-Zhuang; Harmon, Bruce; Ho, Kai-Ming

2012-03-09

Using genetic algorithm with first-principle calculations, we searched for low-energy crystal structures of Fe1?xCox alloys. We found that Fe1?xCox alloys are highly configurationally degenerate with many additional off-stoichiometric stable structures to the well-known B2 structure. The average magnetic moment of Fe atom increases with concentration of Co in the alloy, while that of Co atom is almost constant, which are consistent with experiments and earlier studies. The magnetic moment of Fe atom is strongly dependent on the number of Co nearest neighbor and it increases with this number.

5. Atomic Beam Magnetic Resonance: A New Way to Study High-Tc Superconductors

Lafyatis, Gregory P.

1996-05-01

A magnetic field penetrates a type-II superconductor by forming an Abrikosov lattice'' of magnetic flux tubes or vortices. As the temperature is increased in a High Tc sample, vortices become free to move and if current is being driven through the sample, this vortex motion will dissipate energy. This dissipative vortex motion is BOTH the major obstacle to many envisioned High-Tc commercial applications AND a source of novel physical phenomena. We (Coauthor's of the present work are Harald Hauglin and Nathan Woodard) have developed a way to study vortex lattices using atomic beam magnetic resonance technology. The basic idea is to pass atoms very close to the surface of a superconductor that is penetrated by a magnetic field. In its rest frame an atom will see a fluctuating magnetic field that is determined by the pattern of magnetic vortices at the superconductor's surface and the velocity of the atom. If the fluctuating field has a frequency component coincident with a magnetic transition of the atom, the transition may be driven. Turning things around, by measuring the transition probability for an atom passing over the superconductor as a function of velocity, we are able to study the vortex lattice itself. We have used the magnetic hyperfine transition in ground state potassium to study vortex lattices in both low Tc and high Tc samples. In this talk we will contrast our method with other ways of studying magnetic vortex lattices. We will focus on our most recent work in which we have carried out fundamental studies of vortex lattices in state-of-the-art quality single untwinned crystals of YBCO. (We acknowledge the support of the MISCON program of DOE and NSF's PYI program)

6. Circular Rydberg States of Atomic Hydrogen in an Arbitrary Magnetic Field

Zhao, Li-Bo; B. C., Saha; Du, Meng-Li

2011-09-01

We report a theoretical scheme using a B-spline basis set to improve the poor computational accuracy of circular Rydberg states of hydrogen atoms in the intermediate magnetic field. This scheme can produce high accuracy energy levels and valid for an arbitrary magnetic field. Energy levels of hydrogen are presented for circular Rydberg states with azimuthal quantum numbers |m| = 10-70 as a function of magnetic field strengths ranging from zero to 2.35 × 109 T. The variation of spatial distributions of electron probability densities with magnetic field strengths is discussed and competition between Coulomb and magnetic interactions is illustrated.

7. Bidirectional propagation of cold atoms in a 'stadium'-shaped magnetic guide

SciTech Connect

Wu Saijun; Rooijakkers, Wilbert; Striehl, Pierre; Prentiss, Mara

2004-07-01

We demonstrate the bidirectional propagation of more than 10{sup 7} atoms ({sup 87}Rb) around a 'stadium'-shaped magnetic ring that encloses an area of 10.9 cm{sup 2}, with a flux density exceeding 10{sup 11} atom s{sup -1} cm{sup -2}. Atoms are loaded into the guide from a two-dimensional (and higher) magneto-optical trap at one side of the 'stadium'. An optical standing wave pulse is applied to increase the propagation velocity of atoms along the waveguide. The atom sample fills the entire ring in 200 ms when counterpropagating atom sections of the original atom cloud recombine at their initial positions after a full revolution.

8. Magnetic state selection in atomic frequency and time standards. [hydrogen masers

NASA Technical Reports Server (NTRS)

Peters, H. E.

1982-01-01

Atomic standards such as those based upon cesium and hydrogen rely upon magnetic state selection to obtain population inversion in the hyperfine transition levels. Use of new design approaches and improved magnetic materials has made it possible to fabricate improved state selectors of small size, and thus the efficiency of utilization of beam flux is greatly improved and the size and weight of the standard is reduced. The sensitivity to magnetic perturbations is also decreased, so that the accuracy and stability of the standard is improved. Several new state selector designs are illustrated and the application to standards utilizing different atomic species is analyzed.

9. Monte Carlo simulation of a cesium atom beam in a magnetic field

SciTech Connect

Chen, Jiang Zhu, Hongwei; Ma, Yinguang; Li, Detian; Liu, Zhidong; Wang, Ji

2015-03-07

We present Monte Carlo simulations of the deflection of a beam of {sup 133}Cs atoms in a two wire magnetic field. Our results reveal the relationship between transmission rate of the atoms and incident parameters. Incident angle and position of the beam with maximum transmission are obtained from the simulations. The effect of the deflection field on the spatial distribution (beam profile) of {sup 133}Cs is derived. The method will help with the design of magnetic deflection experiments and to extract the magnetic properties from such experiments.

10. Analytic description of atomic interaction at ultracold temperatures. II. Scattering around a magnetic Feshbach resonance

SciTech Connect

Gao Bo

2011-08-15

Starting from a multichannel quantum-defect theory, we derive analytic descriptions of a magnetic Feshbach resonance in an arbitrary partial wave l and the atomic interactions around it. An analytic formula, applicable to both broad and narrow resonances of arbitrary l, is presented for ultracold atomic scattering around a Feshbach resonance. Other related issues addressed include (a) the parametrization of a magnetic Feshbach resonance of arbitrary l, (b) rigorous definitions of ''broad'' and ''narrow'' resonances of arbitrary l and their different scattering characteristics, and (c) the tuning of the effective range and the generalized effective range by a magnetic field.

11. Hydrogen-like atoms on the surface of neutron stars - Intense magnetic field effects

NASA Technical Reports Server (NTRS)

Williams, A. C.; Darbro, W.; Weisskopf, M. C.; Elsner, R. F.

1985-01-01

It is known that very strong (greater than 1-TG) magnetic fields exist on the surface of some neutron stars. The properties of atoms in fields of this nature are considerably different from those of atoms in field-free regions. Because of the mixing of spherical and cylindrical symmetries, the analytical solution to the problem of a hydrogen atom in a uniform magnetic field is impossible to obtain. In this work, a variational wave function is used to describe the properties of hydrogen like atoms in intense magnetic fields including first-order relativistic effects. Special attention is given to the transition matrix elements for the 2p(0) - 1s(0) transition in Fe XXVI.

12. Multiplet features and magnetic properties of Fe on Cu(111): From single atoms to small clusters

Pacchioni, Giulia E.; Gragnaniello, Luca; Donati, Fabio; Pivetta, Marina; Auts, Gabriel; Yazyev, Oleg V.; Rusponi, Stefano; Brune, Harald

2015-06-01

The observation of sharp atomiclike multiplet features is unexpected for individual 3 d atoms adsorbed on transition-metal surfaces. However, we show by means of x-ray absorption spectroscopy and x-ray magnetic circular dichroism that individual Fe atoms on Cu(111) exhibit such features. They are reminiscent of a low degree of hybridization, similar to 3 d atoms adsorbed on alkali-metal surfaces. We determine the spin, orbital, and total magnetic moments, as well as magnetic anisotropy energy for the individual Fe atoms and for small Fe clusters that we form by increasing the coverage. The multiplet features are smoothened and the orbital moment rapidly decreases with increasing cluster size. For Fe monomers, comparison with density functional theory and multiplet calculations reveals a d7 electronic configuration, owing to the transfer of one electron from the 4 s to the 3 d states.

13. Precisely mapping the magnetic field gradient in vacuum with an atom interferometer

SciTech Connect

Zhou Minkang; Hu Zhongkun; Duan Xiaochun; Sun Buliang; Zhao Jinbo; Luo Jun

2010-12-15

The magnetic field gradient has been measured with an atom interferometer using the magnetic sublevels of {sup 87}Rb atoms. The Doppler-insensitive measurement effectively eliminates the contribution from gravity and background vibration noise, and the differential measurement also can reject some systematic errors. A resolution of 300 pT/mm has been demonstrated with a 90-s integration time and a spatial resolution of 1.4 mm. The gradiometer was then used to measure the magnetic field gradient in an ultrahigh-vacuum environment. The technique will also be very useful to subtract the systematic error arising from the magnetic field inhomogeneity in precision atom-interferometry experiments, such as gravity measurement.

14. Chiral symmetries and Majorana fermions in coupled magnetic atomic chains on a superconductor

Xiao, Jinpeng; An, Jin

2015-11-01

We study the magnetic structures and their connections with topological superconductivity due to the proximity effect for coupled magnetic atomic chains deposited on a superconductor. Several magnetic phases are self-consistently determined, including both the coplanar and noncoplanar ones. For an N-chain triangular atomic ladder, topologically nontrivial superconducting states can always be realized, but strongly depend on its magnetic structure and the number of atomic chains. When N is even, the topologically nontrivial states with noncoplanar structures are characterized by {{{Z}}}2 invariants, while the topologically nontrivial noncoplanar states with an odd N are characterized by integer {{Z}} invariants, due to the presence of a new chiral symmetry. The new chiral symmetry for the noncoplanar states is found to be robust against the on-site disorder, as long as the crystal reflection symmetry is respected.

15. A compact design for a magnetic synchrotron to store beams of hydrogen atoms

van der Poel, Aernout P. P.; Dulitz, Katrin; Softley, Timothy P.; Bethlem, Hendrick L.

2015-05-01

We present a design for an atomic synchrotron consisting of 40 hybrid magnetic hexapole lenses arranged in a circle. We show that for realistic parameters, hydrogen atoms with a velocity up to 600 m s-1 can be stored in a 1 m diameter ring, which implies that the atoms can be injected in the ring directly from a pulsed supersonic beam source. This ring can be used to study collisions between stored hydrogen atoms and supersonic beams of many different atoms and molecules. The advantage of using a synchrotron is two-fold: (i) the collision partners move in the same direction as the stored atoms, resulting in a small relative velocity and thus a low collision energy, and (ii) by storing atoms for many round-trips, the sensitivity to collisions is enhanced by a factor of 100-1000. In the proposed ring, the cross-sections for collisions between hydrogen, the most abundant atom in the universe, with any atom or molecule that can be put in a beam, including He, H2, CO, ammonia and OH can be measured at energies below 100 K. We discuss the possibility of using optical transitions to load hydrogen atoms into the ring without influencing the atoms that are already stored. In this way it will be possible to reach high densities of stored hydrogen atoms.

16. Atomic structure, alloying behavior, and magnetism in small Fe-Pt clusters

Chittari, Bheema Lingam; Kumar, Vijay

2015-09-01

We report results of the atomic structure, alloying behavior, and magnetism in F emP tn(m +n =2 -10 ) clusters using projector augmented wave (PAW) pseudopotential method and spin-polarized generalized gradient approximation (GGA) for the exchange-correlation energy. These results are compared with those obtained by using HCTH exchange-correlation functional and LANL2DZ basis set in the Gaussian program and the overall trends are found to be similar. As in bulk Fe-Pt alloys, clusters with equal composition of Fe and Pt have the largest binding energy and the largest heat of nanoalloy formation for a given number of atoms in the cluster. There are some deviations due to the different symmetries in clusters and in cases where the total number of atoms is odd. The lowest energy isomers tend to maximize bonds between unlike atoms with Fe (Pt) atoms occupying high (low) coordination sites in the core (surface) of the cluster. The binding energy, heat of formation, and the second order difference of the total energy show F e2P t2 , F e4P t4 , and F e4P t6 clusters to be the most stable ones among the different clusters we have studied. The magnetic moments on Fe atoms are high in Pt-rich clusters as well as in small Fe-rich clusters and decrease as the aggregation of Fe atoms and the cluster size increases. The maximum value of the magnetic moments on Fe atoms is 3.8 ?B , whereas for Pt atoms it is 1 ?B. These are quite high compared with the values for bulk Fe as well as bulk FePt and F e3Pt phases while bulk Pt is nonmagnetic. There is significant charge transfer from those Fe atoms that interact directly with Pt atoms. We discuss the hybridization between the electronic states of Pt and Fe atoms as well as the variation in the magnetic moments on Fe and Pt atoms. Our results provide insight into the understanding of the nanoalloy behavior of Fe-Pt and we hope that this would help to design Fe based nanoalloys and their assemblies with high magnetic moments for strong magnets without rare earths as well as Pt alloy catalysts.

17. Magnetic blocking in extended metal atom chains: a pentachromium(II) complex behaving as a single-molecule magnet.

PubMed

Cornia, A; Rigamonti, L; Boccedi, S; Clrac, R; Rouzires, M; Sorace, L

2014-12-14

Compound [Cr5(tpda)4Cl2] (H2tpda = N(2),N(6)-di(pyridin-2-yl)pyridine-2,6-diamine), an Extended Metal Atom Chain complex featuring two quadruply-bonded {Cr2} units, exhibits field-induced slow relaxation of its magnetization arising from the terminal chromium(II) ion and provides the first example of a chromium(II)-based Single-Molecule Magnet. PMID:25336023

18. Three-electron atoms and ions in a magnetic field

Salas, J. A.; Pelaschier, I.; Varga, K.

2015-09-01

The energies and physical properties of three-electron systems are studied using an explicitly correlated Gaussian basis optimized by the stochastic variational method. The stability of the system as a function of the nuclear charge is analyzed. The role of the Coulomb and magnetic interactions in shaping the structure of these systems is discussed. The accuracy of the energies is substantially improved for high magnetic fields.

19. Cold magnetically trapped 2Dg scandium atoms. I. Interaction potential

Karman, Tijs; Chu, Xi; Groenenboom, Gerrit C.

2014-11-01

We present a first principles description of the interaction of two ground-state scandium atoms. Scandium has a 2Dg ground state. Thirty molecular states correlate to the lowest dissociation limit of the dimer. In the short range, potential energy curves are calculated using second-order n -electron valence state perturbation theory. The first-order long-range interaction is calculated at the complete active space self-consistent field level. We determine the second-order long-range dispersion interaction from atomic dynamic polarizabilities at imaginary frequencies. These polarizabilities are calculated using time-dependent density functional theory. We merge the short-range approach with the long-range model to obtain a physical description of the 30 potential energy curves correlating to the 2Dg+2Dg limit. Diabatic potentials are presented that can be used in quantum scattering calculations, in order to study Zeeman relaxation of ultracold scandium atoms.

20. Circular Rydberg states of atomic hydrogen in an arbitrary magnetic field

Zhao, L. B.; Saha, B. C.; Du, M. L.

2011-05-01

A theoretical method using a B-spline basis set has been proposed to evaluate circular Rydberg states of atomic hydrogen in a strong magnetic field. The combination of this method and a recently reported finite-basis-set technique can provide a practicable scheme to implement high accuracy computations of circular Rydberg states of atomic hydrogen in an arbitrary magnetic field. Energy levels of hydrogen are presented for circular Rydberg states with azimuthal quantum numbers |m | = 10 - 70 as a function of magnetic field strengths ranging from zero to 2.35 × 109 T. Comparison with available theoretical data shows excellent agreement. The variation of spatial distributions of electron probability densities with magnetic field strengths is discussed and competition between Coulomb and magnetic interactions is illustrated. Supported by NSF-CREST project (grant #0630370).

1. Magnetic merging of ultracold atomic gases of {sup 85}Rb and {sup 87}Rb

SciTech Connect

Haendel, S.; Wiles, T. P.; Marchant, A. L.; Hopkins, S. A.; Adams, C. S.; Cornish, S. L.

2011-05-15

We report the magnetic merging of ultracold atomic gases of {sup 85}Rb and {sup 87}Rb by the controlled overlap of two initially spatially separated magnetic traps. We present a detailed analysis of the combined magnetic-field potential as the two traps are brought together that predicts a clear optimum trajectory for the merging. We verify this prediction experimentally using {sup 85}Rb and find that the final atom number in the merged trap is maximized with minimal heating by following the predicted optimum trajectory. Using the magnetic-merging approach allows us to create variable-ratio isotopic Rb mixtures with a single laser-cooling setup by simply storing one isotope in a magnetic trap before jumping the laser frequencies to the transitions necessary to laser cool the second isotope.

2. Magnetic-field-induced enhancement of atomic stabilization in intense high-frequency laser fields

Simonsen, Aleksander Skjerlie; Frre, Morten

2015-07-01

The role of the magnetic-field component of the laser pulse on the phenomenon of atomic stabilization is investigated in an ab initio study. This is achieved by solving the time-dependent Schrdinger equation for the laser-atom interaction beyond the dipole approximation. The system under study is atomic hydrogen and the atom is assumed to be irradiated by an intense xuv laser light pulse of varying intensity and duration. We consider two different photon energies, ? ? =54 and 95 eV. The main finding is that there exists a range of laser pulse durations lasting for a few tens of field cycles where the atomic stabilization effect is enhanced due to the magnetic-field component. This is a rather surprising result that contradicts earlier statements made in the few-cycle pulse regime, where it has been shown that the magnetic field has a destructive effect in that the degree of stabilization is suppressed. It is further found that in the long-pulse limit the ionization probabilities obtained when illuminating the target with dipole and nondipole fields eventually coincide, meaning that the magnetic-field component of the laser field finally loses its significance in the context of atomic stabilization. It is also found that within the window of enhanced stabilization, the surplus population is distributed among excited bound states rather than in the initial ground state.

3. Electronic and magnetic properties of nonmetal atoms adsorbed ReS2 monolayers

Zhang, Xiaoou; Li, Qingfang

2015-08-01

The stable configurations and electronic and magnetic properties of nonmetal atoms (H, N, P, O, S, F, and Cl) adsorbed ReS2 monolayers have been investigated by first-principles calculations. It is found that H, O, S, F, and Cl prefer to occupy the peak sites of S atoms, while both N and P atoms favor the valley sites of S atoms. The ReS2 sheet exhibits a good adsorption capability to nonmetal atoms. The reconstruction of the surface is pronounced in N- and P-adsorbed ReS2 monolayers. In H-adsorbed case, the Fermi level is pulled into the conduction band, which results in the semiconductor-metal transition. The same magnetic moment of 1?B is found in the N-, P-, F-, and Cl-adsorbed ReS2 monolayers, while the mechanisms of forming magnetic moment for N (P)- and F (Cl)-adsorbed cases are different. In addition, the spatial extensions of spin density in P-, F-, and Cl-adsorbed cases are larger than that in N-adsorbed case, which is more suitable to achieve long-range magnetic coupling interaction at low defect concentrations. Our results provide insight for achieving metal-free magnetism and a tunable band gap for various electronic and spintronic devices based on ReS2.

4. Electronic structures and magnetic properties of rare-earth-atom-doped BNNTs

Ren, Juan; Zhang, Ning-Chao; Wang, Peng; Ning, Chao; Zhang, Hong; Peng, Xiao-Juan

2016-04-01

Stable geometries, electronic structures, and magnetic properties of (8,0) and (4,4) single-walled BN nanotubes (BNNTs) doped with rare-earth (RE) atoms are investigated using the first-principles pseudopotential plane wave method with density functional theory (DFT). The results show that these RE atoms can be effectively doped in BNNTs with favorable energies. Because of the curvature effect, the values of binding energy for RE-atom-doped (4,4) BNNTs are larger than those of the same atoms on (8,0) BNNTs. Electron transfer between RE-5 d, 6 s, and B-2 p, N-2 p orbitals was also observed. Furthermore, electronic structures and magnetic properties of BNNTs can be modified by such doping. The results show that the adsorption of Ce, Pm, Sm, and Eu atoms can induce magnetization, while no magnetism is observed when BNNTs are doped with La. These results are useful for spintronics applications and for developing magnetic nanostructures.

5. Wireless power transfer based on magnetic metamaterials consisting of assembled ultra-subwavelength meta-atoms

Wu, Q.; Li, Y. H.; Gao, N.; Yang, F.; Chen, Y. Q.; Fang, K.; Zhang, Y. W.; Chen, H.

2015-03-01

In this letter, a potential way to transfer power wirelessly based on magnetic metamaterials (MMs) assembled by ultra-subwavelength meta-atoms is proposed. Frequency-domain simulation and experiments are performed for accurately obtaining effective permeability of magnetic metamaterials. The results demonstrate that MMs possess great power for enhancing the wireless power transfer efficiency between two non-resonant coils. Further investigations on the magnetic-field distribution demonstrate that a large-area flattened magnetic field in near range can be effectively realized, exhibiting great flexibility in assembling.

6. Atomic-Scale Interfacial Magnetism in Fe/Graphene Heterojunction.

PubMed

Liu, W Q; Wang, W Y; Wang, J J; Wang, F Q; Lu, C; Jin, F; Zhang, A; Zhang, Q M; van der Laan, G; Xu, Y B; Li, Q X; Zhang, R

2015-01-01

Successful spin injection into graphene makes it a competitive contender in the race to become a key material for quantum computation, or the spin-operation-based data processing and sensing. Engineering ferromagnetic metal (FM)/graphene heterojunctions is one of the most promising avenues to realise it, however, their interface magnetism remains an open question up to this day. In any proposed FM/graphene spintronic devices, the best opportunity for spin transport could only be achieved where no magnetic dead layer exists at the FM/graphene interface. Here we present a comprehensive study of the epitaxial Fe/graphene interface by means of X-ray magnetic circular dichroism (XMCD) and density functional theory (DFT) calculations. The experiment has been performed using a specially designed FM1/FM2/graphene structure that to a large extent restores the realistic case of the proposed graphene-based transistors. We have quantitatively observed a reduced but still sizable magnetic moments of the epitaxial Fe ML on graphene, which is well resembled by simulations and can be attributed to the strong hybridization between the Fe 3dz2 and the C 2pz orbitals and the sp-orbital-like behavior of the Fe 3d electrons due to the presence of graphene. PMID:26145155

7. Atomic-Scale Interfacial Magnetism in Fe/Graphene Heterojunction

PubMed Central

Liu, W. Q.; Wang, W. Y.; Wang, J. J.; Wang, F. Q.; Lu, C.; Jin, F.; Zhang, A.; Zhang, Q. M.; Laan, G. van der; Xu, Y. B.; Li, Q. X.; Zhang, R.

2015-01-01

Successful spin injection into graphene makes it a competitive contender in the race to become a key material for quantum computation, or the spin-operation-based data processing and sensing. Engineering ferromagnetic metal (FM)/graphene heterojunctions is one of the most promising avenues to realise it, however, their interface magnetism remains an open question up to this day. In any proposed FM/graphene spintronic devices, the best opportunity for spin transport could only be achieved where no magnetic dead layer exists at the FM/graphene interface. Here we present a comprehensive study of the epitaxial Fe/graphene interface by means of X-ray magnetic circular dichroism (XMCD) and density functional theory (DFT) calculations. The experiment has been performed using a specially designed FM1/FM2/graphene structure that to a large extent restores the realistic case of the proposed graphene-based transistors. We have quantitatively observed a reduced but still sizable magnetic moments of the epitaxial Fe ML on graphene, which is well resembled by simulations and can be attributed to the strong hybridization between the Fe 3dz2 and the C 2pz orbitals and the sp-orbital-like behavior of the Fe 3d electrons due to the presence of graphene. PMID:26145155

8. Ultra-sensitive Magnetic Microscopy with an Atomic Magnetometer

SciTech Connect

Kim, Young Jin

2015-08-19

The PowerPoint presentation focused on research goals, specific information about the atomic magnetometer, response and resolution factors of the SERF magnetometer, FC+AM systems, tests of field transfer and resolution on FC, gradient cancellation, testing of AM performance, ideas for a multi-channel AM, including preliminary sensitivity testing, and a description of a 6 channel DAQ system. A few ideas for future work ended the presentation.

9. Excitation of simple atoms by slow magnetic monopoles

SciTech Connect

Kroll, N.M.; Parke, S.J.; Ganapathi, V.; Drell, S.D.

1984-01-01

We present a theory of excitation of simple atoms by slow moving massive monopoles. Previously presented results for a monopole of Dirac strength on hydrogen and helium are reviewed. The hydrogen theory is extended to include arbitrary integral multiples of the Dirac pole strength. The excitation of helium by double strength poles and by dyons is also discussed. It is concluded that a helium proportional counter is a reliable and effective detector for monopoles of arbitrary strength, and for negatively charged dyons.

10. Velocity-selected magnetic guiding of Zeeman-decelerated hydrogen atoms

Dulitz, Katrin; Softley, Timothy P.

2016-01-01

An original design of magnetic guide is presented, suitable for use with Zeeman-decelerated supersonic beams of ground-state hydrogen atoms and other light paramagnetic species. Three-dimensional particle trajectory simulations show that, by combining a series of permanent-magnet Halbach arrays with pulsed high-current wire electromagnets, this guide can be used to efficiently transmit the slow, decelerated atoms and discard the faster, undecelerated atoms and other species in the gas beam. The curved guide would be suitable for guiding hydrogen atoms into an ion trap to investigate low temperature ion-molecule collisions. It is also shown that the device could be used for the guiding or velocity selection from an undecelerated supersonic or effusive beam.

11. Magnetic induction tomography using an all-optical ??Rb atomic magnetometer.

PubMed

Wickenbrock, Arne; Jurgilas, Sarunas; Dow, Albert; Marmugi, Luca; Renzoni, Ferruccio

2014-11-15

We demonstrate magnetic induction tomography (MIT) with an all-optical atomic magnetometer. Our instrument creates a conductivity map of conductive objects. Both the shape and size of the imaged samples compare very well with the actual shape and size. Given the potential of all-optical atomic magnetometers for miniaturization and extreme sensitivity, the proof-of-principle presented in this Letter opens up promising avenues in the development of instrumentation for MIT. PMID:25490470

12. Magnetic-film atom chip with 10 μm period lattices of microtraps for quantum information science with Rydberg atoms

SciTech Connect

Leung, V. Y. F.; Complex Photonic Systems , MESA Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede ; Pijn, D. R. M.; Schlatter, H.; Torralbo-Campo, L.; La Rooij, A. L.; Mulder, G. B.; Naber, J.; Soudijn, M. L.; Tauschinsky, A.; Spreeuw, R. J. C.; Abarbanel, C.; Hadad, B.; Golan, E.; Folman, R.

2014-05-15

We describe the fabrication and construction of a setup for creating lattices of magnetic microtraps for ultracold atoms on an atom chip. The lattice is defined by lithographic patterning of a permanent magnetic film. Patterned magnetic-film atom chips enable a large variety of trapping geometries over a wide range of length scales. We demonstrate an atom chip with a lattice constant of 10 μm, suitable for experiments in quantum information science employing the interaction between atoms in highly excited Rydberg energy levels. The active trapping region contains lattice regions with square and hexagonal symmetry, with the two regions joined at an interface. A structure of macroscopic wires, cutout of a silver foil, was mounted under the atom chip in order to load ultracold {sup 87}Rb atoms into the microtraps. We demonstrate loading of atoms into the square and hexagonal lattice sections simultaneously and show resolved imaging of individual lattice sites. Magnetic-film lattices on atom chips provide a versatile platform for experiments with ultracold atoms, in particular for quantum information science and quantum simulation.

13. Magnetic-field-tunable Kondo effect in alkaline-earth cold atoms

Isaev, Leonid; Rey, Ana Maria

2015-05-01

We study quantum magnetism in strongly interacting fermionic alkaline-earth atoms (AEAs). Due to the decoupling of electronic and nuclear degrees of freedom, AEAs in two lowest electronic states (1S0 and 3P0) obey an accurate SU(N 2 I + 1) symmetry in their two-body collisions (I is the nuclear spin). We consider a system that realizes the simplest SU(2) case (for atoms prepared in two nuclear-spin states) in an optical lattice with two bands: one localized and one itinerant. For the fully filled narrow band (two atoms per lattice site) we demonstrate that an applied magnetic field provides an efficient control of the local ground state degeneracy due to mixing of spin and orbital two-body states. We derive an effective low-energy model that includes this magnetic-field effect as well as atomic interactions in the two optical lattice bands, and show that it exhibits a peculiar phenomenon of a magnetic field-induced Kondo effect, so far observed only in Coulomb blockaded quantum dots. We expect that our results can be tested with ultracold 173 Yb or 87 Sr atoms. Supported by JILA-NSF-PFC-1125844, NSF-PIF-1211914, ARO, AFOSR, AFOSR-MURI.

14. Perturbations of the hydrogen atom by inhomogeneous static electric and magnetic fields

2015-03-01

The hydrogen atom is a specific, and physically relevant, Keplerian two-body system with one of the bodies assumed infinitely heavy. Isochronous integrable n-shell approximations for the perturbations of the hydrogen atom, known as Stark and Zeeman effects in the presence of homogeneous electric and magnetic fields, respectively, have been widely studied. In order to go beyond the set of linear systems, we considered perturbations by inhomogeneous electromagnetic fields. In particular, we found that the perturbation by a generic inhomogeneous magnetic field results in an approximately integrable anisochronous system which can be described as two rigid Euler tops coupled through higher order terms.

15. Achieving atomic resolution magnetic dichroism by controlling the phase symmetry of an electron probe

SciTech Connect

Rusz, Jan; Idrobo, Juan -Carlos; Bhowmick, Somnath

2014-09-30

The calculations presented here reveal that an electron probe carrying orbital angular momentum is just a particular case of a wider class of electron beams that can be used to measure electron magnetic circular dichroism (EMCD) with atomic resolution. It is possible to obtain an EMCD signal with atomic resolution by simply breaking the symmetry of the electron probe phase front using the aberration-corrected optics of an scanning transmission electron microscope. The phase distribution of the probe depends on the magnetic symmetry and crystal structure of the sample. The calculations indicate that EMCD signals utilizing the phase of the electron probe are as strong as those obtained by nanodiffraction methods.

16. Microrheology of cells with magnetic force modulation atomic force microscopy.

PubMed

Reblo, L M; de Sousa, J S; Mendes Filho, J; Schpe, J; Doschke, H; Radmacher, M

2014-04-01

We propose a magnetic force modulation method to measure the stiffness and viscosity of living cells using a modified AFM apparatus. An oscillating magnetic field makes a magnetic cantilever oscillate in contact with the sample, producing a small AC indentation. By comparing the amplitude of the free cantilever motion (A0) with the motion of the cantilever in contact with the sample (A1), we determine the sample stiffness and viscosity. To test the method, the frequency-dependent stiffness of 3T3 fibroblasts was determined as a power law k(s)(f) = ? + ?(f/f)(?) (? = 7.6 10(-4) N m(-1), ? = 1.0 10(-4) N m(-1), f = 1 Hz, ? = 0.6), where the coefficient ? = 0.6 is in good agreement with rheological data of actin solutions with concentrations similar to those in cells. The method also allows estimation of the internal friction of the cells. In particular we found an average damping coefficient of 75.1 ?N s m(-1) for indentation depths ranging between 1.0 ?m and 2.0 ?m. PMID:24651941

17. Simulating Chiral Magnetic and Separation Effects with Spin-Orbit Coupled Atomic Gases.

PubMed

Huang, Xu-Guang

2016-01-01

The chiral magnetic and chiral separation effects-quantum-anomaly-induced electric current and chiral current along an external magnetic field in parity-odd quark-gluon plasma-have received intense studies in the community of heavy-ion collision physics. We show that analogous effects occur in rotating trapped Fermi gases with Weyl-Zeeman spin-orbit coupling where the rotation plays the role of an external magnetic field. These effects can induce a mass quadrupole in the atomic cloud along the rotation axis which may be tested in future experiments. Our results suggest that the spin-orbit coupled atomic gases are potential simulators of the chiral magnetic and separation effects. PMID:26868084

18. Remote energetic neutral atom imaging of electric potential over a lunar magnetic anomaly

Abstract<p label="1">The formation of electric potential over lunar <span class="hlt">magnetized</span> regions is essential for understanding fundamental lunar science, for understanding the lunar environment, and for planning human exploration on the Moon. A large positive electric potential was predicted and detected from single point measurements. Here, we demonstrate a remote imaging technique of electric potential mapping at the lunar surface, making use of a new concept involving hydrogen neutral <span class="hlt">atoms</span> derived from solar wind. We apply the technique to a lunar <span class="hlt">magnetized</span> region using an existing dataset of the neutral <span class="hlt">atom</span> energy spectrometer SARA/CENA on Chandrayaan-1. Electrostatic potential larger than +135 V inside the Gerasimovic anomaly is confirmed. This structure is found spreading all over the <span class="hlt">magnetized</span> region. The widely spread electric potential can influence the local plasma and dust environment near the <span class="hlt">magnetic</span> anomaly.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4751543','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4751543"><span id="translatedtitle">Simulating Chiral <span class="hlt">Magnetic</span> and Separation Effects with Spin-Orbit Coupled <span class="hlt">Atomic</span> Gases</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Huang, Xu-Guang</p> <p>2016-01-01</p> <p>The chiral <span class="hlt">magnetic</span> and chiral separation effects—quantum-anomaly-induced electric current and chiral current along an external <span class="hlt">magnetic</span> field in parity-odd quark-gluon plasma—have received intense studies in the community of heavy-ion collision physics. We show that analogous effects occur in rotating trapped Fermi gases with Weyl-Zeeman spin-orbit coupling where the rotation plays the role of an external <span class="hlt">magnetic</span> field. These effects can induce a mass quadrupole in the <span class="hlt">atomic</span> cloud along the rotation axis which may be tested in future experiments. Our results suggest that the spin-orbit coupled <span class="hlt">atomic</span> gases are potential simulators of the chiral <span class="hlt">magnetic</span> and separation effects. PMID:26868084</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999PhyS...59..411X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999PhyS...59..411X"><span id="translatedtitle">Geometric Phases and Probabilities for an Alkali <span class="hlt">Atom</span> in a Strong <span class="hlt">Magnetic</span> Field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, Jing-Bo; Yao, Dao-Xin</p> <p></p> <p>A general formalism of time evolution and geometric phase for a system with a dynamical semisimple Lie algebra is presented. The formalism is then used to study an alkali <span class="hlt">atom</span> in a strong time-dependent <span class="hlt">magnetic</span> field. The non-adiabatic transition probability among the angular momentum states is also calculated. Finally, explicit expressions for the geometric phase and probability in particular case of a rotating <span class="hlt">magnetic</span> field are given.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/385737','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/385737"><span id="translatedtitle"><span class="hlt">Magnetic</span> Dichroism in the Angular Distribution of <span class="hlt">Atomic</span> Oxygen {bold 2}{ital p} Photoelectrons</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Plotzke, O.; Pruemper, G.; Zimmermann, B.; Becker, U.; Kleinpoppen, H.</p> <p>1996-09-01</p> <p>A substantial difference in the angular distributions of 2{ital p} photoelectrons from polarized oxygen <span class="hlt">atoms</span> was found for two antiparallel <span class="hlt">atomic</span> polarizations. This <span class="hlt">magnetic</span> dichroism was studied as a function of photon energy from 25 to 52eV. Our method extends traditional photoelectron angular distribution measurements of open shell <span class="hlt">atoms</span> to {open_quote}{open_quote}complete{close_quote}{close_quote} experiments in similar to spin-resolved measurements. The observed dichroism allows a determination of the dipole matrix elements for the {epsilon}{ital s} and {epsilon}{ital d} photoelectrons and their phase difference including the sign. {copyright} {ital 1996 The American Physical Society.}</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20052146','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20052146"><span id="translatedtitle">Adiabatically induced coherent Josephson oscillations of ultracold <span class="hlt">atoms</span> in an asymmetric two-dimensional <span class="hlt">magnetic</span> lattice.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Abdelrahman, A; Hannaford, P; Alameh, K</p> <p>2009-12-21</p> <p>We propose a new method to create an asymmetric two-dimensional <span class="hlt">magnetic</span> lattice which exhibits <span class="hlt">magnetic</span> band gap structure similar to semiconductor devices. The quantum device is assumed to host bound states of collective excitations formed in a <span class="hlt">magnetically</span> trapped quantum degenerate gas of ultracold <span class="hlt">atoms</span> such as a Bose-Einstein condensate (BEC) or a degenerate Fermi gas. A theoretical framework is established to describe possible realization of the exciton-Mott to discharging Josephson states oscillations in which the adiabatically controlled oscillations induce ac and dc Josephson <span class="hlt">atomic</span> currents where this effect can be used to transfer n Josephson qubits across the asymmetric two-dimensional <span class="hlt">magnetic</span> lattice. We consider second-quantized Hamiltonians to describe the Mott insulator state and the coherence of multiple tunneling between adjacent <span class="hlt">magnetic</span> lattice sites where we derive the self consistent non-linear Schrdinger equation with a proper field operator to describe the exciton Mott quantum phase transition via the induced Josephson <span class="hlt">atomic</span> current across the n <span class="hlt">magnetic</span> bands. PMID:20052146</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21016031','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21016031"><span id="translatedtitle">Optical lattice polarization effects on <span class="hlt">magnetically</span> induced optical <span class="hlt">atomic</span> clock transitions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Taichenachev, A. V.; Yudin, V. I.; Oates, C. W.</p> <p>2007-08-15</p> <p>We derive the frequency shift for a forbidden optical transition J=0{yields}J{sup '}=0 caused by the simultaneous actions of an elliptically polarized lattice field and a static <span class="hlt">magnetic</span> field. We find that a simple configuration of lattice and <span class="hlt">magnetic</span> fields leads to a cancellation of this shift to first order in lattice intensity and <span class="hlt">magnetic</span> field. In this geometry, the second-order lattice intensity shift can be minimized as well by use of optimal lattice polarization. Suppression of these shifts could considerably enhance the performance of the next generation of <span class="hlt">atomic</span> clocks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013APS..DMP.P3005N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013APS..DMP.P3005N"><span id="translatedtitle">A permanent <span class="hlt">magnet</span> trap for buffer gas cooled <span class="hlt">atoms</span> and molecules</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nohlmans, D.; Skoff, S. M.; Hendricks, R. J.; Segal, D. M.; Sauer, B. E.; Hinds, E. A.; Tarbutt, M. R.</p> <p>2013-05-01</p> <p>Cold molecules are set to provide a wealth of new science compared to their <span class="hlt">atomic</span> counterparts. Here we want to present preliminary results for cooling and trapping <span class="hlt">atoms</span>/molecules in a permanent <span class="hlt">magnetic</span> trap. By replacing the conventional buffer gas cell with an arrangement of permanent <span class="hlt">magnets</span>, we will be able to trap a fraction of the molecules right where they are cooled. For this purpose we have designed a quadrupole trap using NdFeB <span class="hlt">magnets</span>, which has a trap depth of 0.4 K for molecules with a <span class="hlt">magnetic</span> moment of 1 ?B. Cold helium gas is pulsed into the trap region by a solenoid valve and the <span class="hlt">atoms</span>/molecules are subsequently ablated into this and cooled via elastic collisions, leaving a fraction of them trapped. This new set-up is currently being tested with lithium <span class="hlt">atoms</span> as they are easier to make. After having optimised the trapping and detection processes, we will use the same trap for YbF molecules.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3397402','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3397402"><span id="translatedtitle">Single-molecule force spectroscopy: optical tweezers, <span class="hlt">magnetic</span> tweezers and <span class="hlt">atomic</span> force microscopy</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Neuman, Keir C.; Nagy, Attila</p> <p>2012-01-01</p> <p>Single-molecule force spectroscopy has emerged as a powerful tool to investigate the forces and motions associated with biological molecules and enzymatic activity. The most common force spectroscopy techniques are optical tweezers, <span class="hlt">magnetic</span> tweezers and <span class="hlt">atomic</span> force microscopy. These techniques are described and illustrated with examples highlighting current capabilities and limitations. PMID:18511917</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22027951','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22027951"><span id="translatedtitle">On the spectrum of the hydrogen <span class="hlt">atom</span> in an ultrastrong <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Popov, V. S.; Karnakov, B. M.</p> <p>2012-01-15</p> <p>Various approaches to computing the energies of the ground state and excited levels of the hydrogen <span class="hlt">atom</span> in an ultrastrong <span class="hlt">magnetic</span> field B that considerably exceeds the field B{sub a} = m{sub e}{sup 2}e{sup 3}c/h{sup 3} {approx} 10{sup 9} G are considered. The effects of polarization of vacuum and anomalous <span class="hlt">magnetic</span> moment of the electron on the position of the <span class="hlt">atomic</span> levels are discussed. The vacuum polarization effects are negligibly weak for B < 10{sup 15} G but become significant in fields B Much-Greater-Than 10{sup 16} G, in which these effects qualitatively modify the <span class="hlt">atomic</span> spectrum in this range. The difference in the behaviors of the even and odd energy levels for B Much-Greater-Than B{sub a} is analyzed and the formulas for the energies of odd levels as a function of field B are refined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26852801','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26852801"><span id="translatedtitle">Probing of multiple <span class="hlt">magnetic</span> responses in <span class="hlt">magnetic</span> inductors using <span class="hlt">atomic</span> force microscopy.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Park, Seongjae; Seo, Hosung; Seol, Daehee; Yoon, Young-Hwan; Kim, Mi Yang; Kim, Yunseok</p> <p>2016-01-01</p> <p>Even though nanoscale analysis of <span class="hlt">magnetic</span> properties is of significant interest, probing methods are relatively less developed compared to the significance of the technique, which has multiple potential applications. Here, we demonstrate an approach for probing various <span class="hlt">magnetic</span> properties associated with eddy current, coil current and <span class="hlt">magnetic</span> domains in <span class="hlt">magnetic</span> inductors using multidimensional <span class="hlt">magnetic</span> force microscopy (MMFM). The MMFM images provide combined <span class="hlt">magnetic</span> responses from the three different origins, however, each contribution to the MMFM response can be differentiated through analysis based on the bias dependence of the response. In particular, the bias dependent MMFM images show locally different eddy current behavior with values dependent on the type of materials that comprise the MI. This approach for probing <span class="hlt">magnetic</span> responses can be further extended to the analysis of local physical features. PMID:26852801</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4745108','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4745108"><span id="translatedtitle">Probing of multiple <span class="hlt">magnetic</span> responses in <span class="hlt">magnetic</span> inductors using <span class="hlt">atomic</span> force microscopy</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Park, Seongjae; Seo, Hosung; Seol, Daehee; Yoon, Young-Hwan; Kim, Mi Yang; Kim, Yunseok</p> <p>2016-01-01</p> <p>Even though nanoscale analysis of <span class="hlt">magnetic</span> properties is of significant interest, probing methods are relatively less developed compared to the significance of the technique, which has multiple potential applications. Here, we demonstrate an approach for probing various <span class="hlt">magnetic</span> properties associated with eddy current, coil current and <span class="hlt">magnetic</span> domains in <span class="hlt">magnetic</span> inductors using multidimensional <span class="hlt">magnetic</span> force microscopy (MMFM). The MMFM images provide combined <span class="hlt">magnetic</span> responses from the three different origins, however, each contribution to the MMFM response can be differentiated through analysis based on the bias dependence of the response. In particular, the bias dependent MMFM images show locally different eddy current behavior with values dependent on the type of materials that comprise the MI. This approach for probing <span class="hlt">magnetic</span> responses can be further extended to the analysis of local physical features. PMID:26852801</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20898638','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20898638"><span id="translatedtitle">Spectroscopic Studies of <span class="hlt">Atomic</span> and Molecular Processes in the Edge Region of <span class="hlt">Magnetically</span> Confined Fusion Plasmas</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hey, J. D.; Brezinsek, S.; Mertens, Ph.; Unterberg, B.</p> <p>2006-12-01</p> <p>Edge plasma studies are of vital importance for understanding plasma-wall interactions in <span class="hlt">magnetically</span> confined fusion devices. These interactions determine the transport of neutrals into the plasma, and the properties of the plasma discharge. This presentation deals with optical spectroscopic studies of the plasma boundary, and their role in elucidating the prevailing physical conditions. Recorded spectra are of four types: emission spectra of ions and <span class="hlt">atoms</span>, produced by electron impact excitation and by charge-exchange recombination, <span class="hlt">atomic</span> spectra arising from electron impact-induced molecular dissociation and ionisation, visible spectra of molecular hydrogen and its isotopic combinations, and laser-induced fluorescence (LIF) spectra. The <span class="hlt">atomic</span> spectra are strongly influenced by the confining <span class="hlt">magnetic</span> field (Zeeman and Paschen-Back effects), which produces characteristic features useful for species identification, temperature determination by Doppler broadening, and studies of chemical and physical sputtering. Detailed analysis of the Zeeman components in both optical and LIF spectra shows that <span class="hlt">atomic</span> hydrogen is produced in various velocity classes, some related to the relevant molecular Franck-Condon energies. The latter reflect the dominant electron collision processes responsible for production of <span class="hlt">atoms</span> from molecules. This assignment has been verified by gas-puffing experiments through special test limiters. The higher-energy flanks of hydrogen line profiles probably also show the influence of charge-exchange reactions with molecular ions accelerated in the plasma sheath ('scrape-off layer') separating limiter surfaces from the edge plasma, in analogy to acceleration in the cathode-fall region of gas discharges. While electron collisions play a vital role in generating the spectra, ion collisions with excited <span class="hlt">atomic</span> radiators act through re-distribution of population among the <span class="hlt">atomic</span> fine-structure sublevels, and momentum transfer to the <span class="hlt">atomic</span> nuclei via ion-induced dipole collisions with the bound electrons. The ions are thus important in randomising and equilibrating the velocity distribution of <span class="hlt">atomic</span> products of molecular dissociation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6064665','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6064665"><span id="translatedtitle">Localized <span class="hlt">magnetic</span> moments on chromium and manganese dopant <span class="hlt">atoms</span> in niobium and vanadium</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Roy, A.; Buchanan, D.S.; Holmgren, D.J.; Ginsberg, D.M.</p> <p>1985-03-01</p> <p>We have made <span class="hlt">magnetic</span> susceptibility measurements on films of Nb and V, pure and doped with Cr and Mn. The results indicate the presence of localized moments on Cr and Mn dopant <span class="hlt">atoms</span> in both Nb and V. We discuss the data in terms of a model which takes the <span class="hlt">magnetic</span> behavior of the host metals into account. We have also measured the superconducting transition temperature, T/sub c/, and the upper critical <span class="hlt">magnetic</span> field, H/sub c/2(T), of several Nb films, pure and doped with Cr and Mn. We find that T/sub c/ of Nb is decreased in the presence of Cr or Mn, by amounts that are consistent with the existence of localized moments. The results for H/sub c/2(T) indicate, for both Cr and Mn dopants in Nb, that the pair-breaking effect of the <span class="hlt">magnetic</span> dopants is additive with that of the applied <span class="hlt">magnetic</span> field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25526151','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25526151"><span id="translatedtitle"><span class="hlt">Magnetism</span> of Ho and Er <span class="hlt">atoms</span> on close-packed metal surfaces.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Donati, F; Singha, A; Stepanow, S; Wckerlin, C; Dreiser, J; Gambardella, P; Rusponi, S; Brune, H</p> <p>2014-12-01</p> <p>We investigated the <span class="hlt">magnetic</span> properties of individual Ho <span class="hlt">atoms</span> adsorbed on the (111) surface of Pt, which have been recently claimed to display single ion <span class="hlt">magnetic</span> behavior. By combining x-ray absorption spectroscopy and <span class="hlt">magnetic</span> dichroism measurements with ligand field multiplet calculations, we reveal a ground state which is incompatible with long spin relaxation times, in disagreement with former findings. A comparative study of the ground state and <span class="hlt">magnetic</span> anisotropy of Ho and Er on Pt(111) and Cu(111) emphasizes the different interaction of the 4f orbitals with localized and delocalized substrate states. In particular, we find a striking rotation of the <span class="hlt">magnetization</span> easy axis for Er, which changes from out of plane on Pt(111) to in plane on Cu(111). PMID:25526151</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSA13C4019P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSA13C4019P"><span id="translatedtitle">Sudden Stratospheric <span class="hlt">Warming</span> Effects over L1 Scintillation at Low Latitude During Quiet and <span class="hlt">Magnetically</span> Disturbed Periods</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Paula, E. R.; Jonah, O. F.; Moraes, A. O.; Kherani, E. A.; Fejer, B. G.; Abdu, M. A.; Batista, I. S.; Negreti, P. M. D. S.; Dutra, S. L. G.; Paes, R. D. R.</p> <p>2014-12-01</p> <p>Small scale irregularities of hundred of meters, associated with bubbles cause scattering and diffraction of radio waves crossing the ionosphere and produces scintillation in amplitude and/or phase of the GNSS signal that can cause loss of lock of its code and/or carrier, affecting the positioning determination. The L1 band GPS amplitude scintillation intensities, represented by the S4 scintillation index, at the low latitude station of So Jos dos Campos (23.1 S, 45.8 W, dip latitude 17.3 S), located under the southern crest of the EIA, were analyzed during two northern hemisphere Sudden Stratospheric <span class="hlt">Warming</span> (SSW) events. These events occurred during the northern winter months of 2003/2004 marked by moderate <span class="hlt">magnetic</span> disturbances and 2012/2013 during a very quiet <span class="hlt">magnetic</span> period. Normally during these months (January to February) moderate to strong scintillation occurs in this Brazilian station for moderate and high solar flux. Long lasting weakening of the scintillation amplitude at this low latitude station was observed during these two SSW events, compared to the pre-SSW periods, however stronger S4 weakening was observed during 2003/2004. The main mechanisms that can lead to scintillation weakening are the meridional neutral wind and the equatorial vertical plasma drift. Since no wind data is available during pre-SSW and SSW periods, we have sought to identify its signature in the latitudinal distribution of the TEC along the 60o <span class="hlt">magnetic</span> meridian and we suggest that a SSW induced southward meridional wind had a large contribution to the S4 weakening. The other mechanism that could have contributed to S4 weakening is the vertical plasma drift. This parameter, inferred from So Lus (2.52S, 44.3W, dip latitude 1.73S) digisonde data for the 17 to 21 LT period during the SSW events, showed predominant decreases around the prereversal hours relative to their pre-SSW periods. The vertical drift during the period of the 2003/2004 SSW event presented a large flattening and remained constant at about 10 m/s. We suggest that this larger drift decrease during the <span class="hlt">magnetic</span> storm, compared to the 2012/2013 SSW period, is caused by the SSW effects reinforced by the disturbance dynamo and overshielding westward polarity electric fields associated with the storm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhRvB..90f4423N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhRvB..90f4423N"><span id="translatedtitle">Structure and <span class="hlt">magnetism</span> of Tm <span class="hlt">atoms</span> and monolayers on W(110)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nistor, Corneliu; Mugarza, Aitor; Stepanow, Sebastian; Gambardella, Pietro; Kummer, Kurt; Diez-Ferrer, Jos Luis; Coffey, David; de la Fuente, Csar; Ciria, Miguel; Arnaudas, Jos I.</p> <p>2014-08-01</p> <p>We investigated the growth and <span class="hlt">magnetic</span> properties of Tm <span class="hlt">atoms</span> and monolayers deposited on a W(110) surface using scanning tunneling microscopy and x-ray <span class="hlt">magnetic</span> circular and linear dichroism. The equilibrium structure of Tm monolayer films is found to be a strongly distorted hexagonal lattice with a Moir pattern due to the overlap with the rectangular W(110) substrate. Monolayer as well as isolated Tm adatoms on W present a trivalent ground-state electronic configuration, contrary to divalent gas phase Tm and weakly coordinated <span class="hlt">atoms</span> in quench-condensed Tm films. Ligand field multiplet simulations of the x-ray absorption spectra further show that Tm has a |J=6,Jz=5> electronic ground state separated by a few meV from the next lowest substates |J=6,Jz=4> and |J=6,Jz=6>. Accordingly, both the Tm <span class="hlt">atoms</span> and monolayer films exhibit large spin and orbital moments with out-of-plane uniaxial <span class="hlt">magnetic</span> anisotropy. X-ray <span class="hlt">magnetic</span> dichroism measurements as a function of temperature show that the Tm monolayers develop antiferromagnetic correlations at about 50 K. The triangular structure of the Tm lattice suggests the presence of significant <span class="hlt">magnetic</span> frustration in this system, which may lead to either a noncollinear staggered spin structure or intrinsic disorder.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22410318','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22410318"><span id="translatedtitle">Confinement effects of <span class="hlt">magnetic</span> field on two-dimensional hydrogen <span class="hlt">atom</span> in plasmas</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bahar, M. K.; Soylu, A.</p> <p>2015-05-15</p> <p>In this study, for the first time, the Schrödinger equation with more general exponential cosine screened Coulomb (MGECSC) potential is solved numerically in the presence and in the absence of an external <span class="hlt">magnetic</span> field within two-dimensional formalism using the asymptotic iteration method. The MGECSC potential includes four different potential forms when considering different sets of the parameters in the potential. The plasma screening effects in the weak and strong <span class="hlt">magnetic</span> field regimes as well as the confinement effects of <span class="hlt">magnetic</span> field on the two-dimensional hydrogen <span class="hlt">atom</span> in Debye and quantum plasmas are investigated by solving the corresponding equations. It is found that applying a uniform <span class="hlt">magnetic</span> field on the hydrogen <span class="hlt">atom</span> embedded in a plasma leads to change in the profile of the total interaction potential. Thus, confinement effects of <span class="hlt">magnetic</span> field on hydrogen <span class="hlt">atom</span> embedded in Debye and quantum plasmas modeled by a MGECSC potential lead to shift bound state energies. This effect would be important to isolate the plasma from the external environment in the experimental applications of plasma physics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26051844','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26051844"><span id="translatedtitle">A first-principles study on the <span class="hlt">magnetic</span> properties of nonmetal <span class="hlt">atom</span> doped phosphorene monolayers.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zheng, Huiling; Zhang, Jianmin; Yang, Baishun; Du, Xiaobo; Yan, Yu</p> <p>2015-07-01</p> <p>In order to induce <span class="hlt">magnetism</span> in two-dimensional semiconductors for their applications in spintronic devices and novel chemical and electronic properties of semiconducting phosphorene, the geometrical structure, electronic and <span class="hlt">magnetic</span> properties of doped phosphorene monolayers with a series of nonmetal <span class="hlt">atoms</span>, including H, F, Cl, Br, I, B, C, Si, N, As, O, S and Se, were systematically investigated using first-principles calculations. The results show that although the substitutional doping of H, F, Cl, Br, I, B, N, O, S or Se results in large structural deformation at the doping sites of phosphorene monolayers, all neutral nonmetal <span class="hlt">atom</span> doped systems are stable. The calculated formation energies reveal that the substitutional doping of numerous nonmetal <span class="hlt">atoms</span> in phosphorene monolayer are possible under appropriate experimental conditions, and the charged dopants C(-), Si(-), S(+) and Se(+) are stable. Moreover, the substitutional doping of H, F, Cl, Br, I, B, N, As, C(-), Si(-), S(+) or Se(+) cannot induce <span class="hlt">magnetism</span> in phosphorene monolayer due to the saturation or pairing of valence electrons of dopant and its neighboring P <span class="hlt">atoms</span>, whereas ground states of neutral C, Si, O, S or Se doped systems are <span class="hlt">magnetic</span> due to the appearance of an unpaired valence electron of C and Si or the formation of a nonbonding 3p electron of a neighboring P <span class="hlt">atom</span> around O, S and Se. Furthermore, the <span class="hlt">magnetic</span> coupling between the moments induced by two Si, O, S or Se are long-range anti-ferromagnetic and the coupling can be attributed to the hybridization interaction involving polarized electrons, whereas the coupling between the moments induced by two C is weak. PMID:26051844</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21437936','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21437936"><span id="translatedtitle">Bloch oscillations of polaritons of an <span class="hlt">atomic</span> ensemble in <span class="hlt">magnetic</span> fields</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zhang, H. R.; Sun, C. P.</p> <p>2010-06-15</p> <p>We study a washboard potential in a light-driven ensemble of three-level <span class="hlt">atoms</span> induced by the externally applied <span class="hlt">magnetic</span> fields under electromagnetically induced transparency (EIT). We find that a dark-state polariton, which is formed by an <span class="hlt">atomic</span> ensemble dressed by the photon can display a typical quantum interference effect (i.e., the quasiparticle Bloch oscillation). The dark-state polariton is subjected to a washboard configuration potential with a spatially uniform force and a periodic potential provided by the linearly and periodically external <span class="hlt">magnetic</span> fields, respectively. Due to the slower group velocity of the photons in the EIT medium, the period of Bloch oscillation can achieve a millisecond order of magnitude. Also, in our protocol, the Bloch oscillation of the dark-state polariton is feasibly modulated through the applied control and <span class="hlt">magnetic</span> fields.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PhRvL.106g3201T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PhRvL.106g3201T"><span id="translatedtitle">Sympathetic Cooling of Polyatomic Molecules with S-State <span class="hlt">Atoms</span> in a <span class="hlt">Magnetic</span> Trap</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tscherbul, T. V.; Yu, H.-G.; Dalgarno, A.</p> <p>2011-02-01</p> <p>We present a rigorous theoretical study of low-temperature collisions of polyatomic molecular radicals with S01 <span class="hlt">atoms</span> in the presence of an external <span class="hlt">magnetic</span> field. Accurate quantum scattering calculations based on ab initio and scaled interaction potentials show that collision-induced spin relaxation of the prototypical organic molecule CH2(X3B1) (methylene) and nine other triatomic radicals in cold He3 gas occurs at a slow rate, demonstrating that cryogenic buffer-gas cooling and <span class="hlt">magnetic</span> trapping of these molecules is feasible with current technology. Our calculations further suggest that it may be possible to create ultracold gases of polyatomic molecules by sympathetic cooling with alkaline-earth <span class="hlt">atoms</span> in a <span class="hlt">magnetic</span> trap.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22072592','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22072592"><span id="translatedtitle">Average <span class="hlt">atom</span> transport properties for pure and mixed species in the hot and <span class="hlt">warm</span> dense matter regimes</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Starrett, C. E.; Kress, J. D.; Collins, L. A.; Hanson, D. E.; Clerouin, J.; Recoules, V.</p> <p>2012-10-15</p> <p>The Kubo-Greenwood formulation for calculation of optical conductivities with an average <span class="hlt">atom</span> model is extended to calculate thermal conductivities. The method is applied to species and conditions of interest for inertial confinement fusion. For the mixed species studied, the partial pressure mixing rule is used. Results including pressures, dc, and thermal conductivities are compared to ab initio calculations. Agreement for pressures is good, for both the pure and mixed species. For conductivities, it is found that the ad hoc renormalization method with line broadening, described in the text, gives best agreement with the ab initio results. However, some disagreement is found and the possible reasons for this are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22402728','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22402728"><span id="translatedtitle"><span class="hlt">Atomic</span> moments in Mn{sub 2}CoAl thin films analyzed by X-ray <span class="hlt">magnetic</span> circular dichroism</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jamer, M. E.; Assaf, B. A.; Heiman, D.; Sterbinsky, G. E.; Arena, D. A.</p> <p>2014-12-07</p> <p>Spin gapless semiconductors are known to be strongly affected by structural disorder when grown epitaxially as thin films. The <span class="hlt">magnetic</span> properties of Mn{sub 2}CoAl thin films grown on GaAs (001) substrates are investigated here as a function of annealing. This study investigates the <span class="hlt">atomic</span>-specific <span class="hlt">magnetic</span> moments of Mn and Co <span class="hlt">atoms</span> measured through X-ray <span class="hlt">magnetic</span> circular dichroism as a function of annealing and the consequent structural ordering. The results indicate that the structural distortion mainly affects the Mn <span class="hlt">atoms</span> as seen by the reduction of the <span class="hlt">magnetic</span> moment from its predicted value.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1174115-atomic-moments-mn2coal-thin-films-analyzed-ray-magnetic-circular-dichroism','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1174115-atomic-moments-mn2coal-thin-films-analyzed-ray-magnetic-circular-dichroism"><span id="translatedtitle"><span class="hlt">Atomic</span> moments in Mn2CoAl thin films analyzed by X-ray <span class="hlt">magnetic</span> circular dichroism</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Jamer, M. E.; Assaf, B. A.; Sterbinsky, G. E.; Arena, D. A.; Heiman, D.</p> <p>2014-12-05</p> <p>Spin gapless semiconductors are known to be strongly affected by structural disorder when grown epitaxially as thin films. The <span class="hlt">magnetic</span> properties of Mn2CoAl thin films grown on GaAs (001) substrates are investigated here as a function of annealing. This study investigates the <span class="hlt">atomic</span>-specific <span class="hlt">magnetic</span> moments of Mn and Co <span class="hlt">atoms</span> measured through X-ray <span class="hlt">magnetic</span> circular dichroism as a function of annealing and the consequent structural ordering. Results indicate that the structural distortion mainly affects the Mn <span class="hlt">atoms</span> as seen by the reduction of the <span class="hlt">magnetic</span> moment from its predicted value.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21544614','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21544614"><span id="translatedtitle"><span class="hlt">Atomic</span> electric dipole moment induced by the nuclear electric dipole moment: The <span class="hlt">magnetic</span> moment effect</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Porsev, S. G.; Ginges, J. S. M.; Flambaum, V. V.</p> <p>2011-04-15</p> <p>We have considered a mechanism for inducing a time-reversal violating electric dipole moment (EDM) in <span class="hlt">atoms</span> through the interaction of a nuclear EDM d{sub N} with the hyperfine interaction, the ''<span class="hlt">magnetic</span> moment effect''. We have derived the operator for this interaction and presented analytical formulas for the matrix elements between <span class="hlt">atomic</span> states. Induced EDMs in the diamagnetic <span class="hlt">atoms</span> {sup 129}Xe, {sup 171}Yb, {sup 199}Hg, {sup 211}Rn, and {sup 225}Ra have been calculated numerically. From the experimental limits on the <span class="hlt">atomic</span> EDMs of {sup 129}Xe and {sup 199}Hg we have placed the following constraints on the nuclear EDMs, |d{sub N}({sup 129}Xe)|<1.1x10{sup -21}|e|cm and |d{sub N}({sup 199}Hg)|<2.8x10{sup -24}|e|cm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3563034','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3563034"><span id="translatedtitle">Reversible Single Spin Control of Individual <span class="hlt">Magnetic</span> Molecule by Hydrogen <span class="hlt">Atom</span> Adsorption</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Liu, Liwei; Yang, Kai; Jiang, Yuhang; Song, Boqun; Xiao, Wende; Li, Linfei; Zhou, Haitao; Wang, Yeliang; Du, Shixuan; Ouyang, Min; Hofer, Werner A.; Castro Neto, Antonio H.; Gao, Hong-Jun</p> <p>2013-01-01</p> <p>The reversible control of a single spin of an <span class="hlt">atom</span> or a molecule is of great interest in Kondo physics and a potential application in spin based electronics. Here we demonstrate that the Kondo resonance of manganese phthalocyanine molecules on a Au(111) substrate have been reversibly switched off and on via a robust route through attachment and detachment of single hydrogen <span class="hlt">atom</span> to the <span class="hlt">magnetic</span> core of the molecule. As further revealed by density functional theory calculations, even though the total number of electrons of the Mn ion remains almost the same in the process, gaining one single hydrogen <span class="hlt">atom</span> leads to redistribution of charges within 3d orbitals with a reduction of the molecular spin state from S = 3/2 to S = 1 that directly contributes to the Kondo resonance disappearance. This process is reversed by a local voltage pulse or thermal annealing to desorb the hydrogen <span class="hlt">atom</span>. PMID:23383378</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/907905','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/907905"><span id="translatedtitle">Construction and applications of an <span class="hlt">atomic</span> <span class="hlt">magnetic</span> gradiometerbased on nonlinear magneto-optical rotation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Xu, Shoujun; Rochester, Simon M.; Yashchuk, Valeriy V.; Donaldson, Marcus H.; Budker, Dmitry</p> <p>2006-06-28</p> <p>We report on the design, characterization, and applicationsof a sensitive <span class="hlt">atomic</span> <span class="hlt">magnetic</span> gradiometer. The device is based onnonlinear magneto-optical rotation in alkali-metal (87Rb) vapor, and usesfrequency-modulated laser light. The <span class="hlt">magnetic</span> field produced by a sampleis detected by measuring the frequency of a resonance in optical rotationthat arises when the modulation frequency equals twice the Larmorprecession frequency of the Rb <span class="hlt">atoms</span>. The gradiometer consists of twoatomic magnetometers. The rotation of light polarization in eachmagnetometer is detected with a balanced polarimeter. The sensitivity ofthe gradiometer is 0.8 nG/Hz1/2 for near-DC (0.1 Hz) <span class="hlt">magnetic</span> fields,with a baseline of 2.5 cm. For applications in nuclear <span class="hlt">magnetic</span> resonance(NMR) and <span class="hlt">magnetic</span> resonance imaging (MRI), a long solenoid that piercesthe <span class="hlt">magnetic</span> shields provides a ~;0.5 G leading field for the nuclearspins in the sample. Our apparatus is particularly suited for remotedetection of NMR and MRI. We demonstrate a point-by-point free inductiondecay measurement and a spin echo reconstructed with a pulse sequencesimilar to the Carr-Purcell-Meiboom-Gill (CPMG) pulse. Additionalapplications and future improvements are also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4728408','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4728408"><span id="translatedtitle">Controlled Phase and Tunable <span class="hlt">Magnetism</span> in Ordered Iron Oxide Nanotube Arrays Prepared by <span class="hlt">Atomic</span> Layer Deposition</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zhang, Yijun; Liu, Ming; Peng, Bin; Zhou, Ziyao; Chen, Xing; Yang, Shu-Ming; Jiang, Zhuang-De; Zhang, Jie; Ren, Wei; Ye, Zuo-Guang</p> <p>2016-01-01</p> <p>Highly-ordered and conformal iron oxide nanotube arrays on an <span class="hlt">atomic</span> scale are successfully prepared by <span class="hlt">atomic</span> layer deposition (ALD) with controlled oxidization states and tunable <span class="hlt">magnetic</span> properties between superparamagnetism and ferrimagnetism. Non-<span class="hlt">magnetic</span> α-Fe2O3 and superparamagnetic Fe3O4 with a blocking temperature of 120 K are in-situ obtained by finely controlling the oxidation reaction. Both of them exhibit a very small grain size of only several nanometers due to the nature of <span class="hlt">atom-by-atom</span> growth of the ALD technique. Post-annealing α-Fe2O3 in a reducing atmosphere leads to the formation of the spinel Fe3O4 phase which displays a distinct ferrimagnetic anisotropy and the Verwey metal-insulator transition that usually takes place only in single crystal magnetite or thick epitaxial films at low temperatures. The ALD deposition of iron oxide with well-controlled phase and tunable <span class="hlt">magnetism</span> demonstrated in this work provides a promising opportunity for the fabrication of 3D nano-devices to be used in catalysis, spintronics, microelectronics, data storages and bio-applications. PMID:26813143</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JAP...118k5703R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JAP...118k5703R"><span id="translatedtitle">Energetics, diffusion, and <span class="hlt">magnetic</span> properties of cobalt <span class="hlt">atom</span> in a monolayer graphene: An ab initio study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Raji, Abdulrafiu T.; Lombardi, Enrico B.</p> <p>2015-09-01</p> <p>We use ab initio methods to study the binding, diffusion, and <span class="hlt">magnetic</span> properties of cobalt <span class="hlt">atom</span> embedded in graphene vacancies. We investigate the diffusion of Co-monovacancy (Co-MV) and Co-divacancy (Co-DV) defect complexes, and determine the minimum energy path (MEP), as well as the activation energy barrier of migration. We obtained similar activation energy barriers, of 5.8 eV, for Co-MV and Co-DV diffusion, respectively. Our calculations also suggest that, at electron-irradiation energy of 200 keV as used in a related experiment, the maximum energy transfer to the Co <span class="hlt">atom</span>, of approximately 9.0 eV is sufficiently high to break metal-carbon bonding. The incident electron energy is also high enough to displace graphene's carbon <span class="hlt">atoms</span> from their lattice positions. The breaking of metal-carbon bonding and the displacement of graphene <span class="hlt">atoms</span> may act to facilitate the migration of Co. We conclude therefore that the detrapping and diffusion of cobalt as observed experimentally is likely to be radiation-induced, similar to what has been observed for Au and Fe in electron-irradiated graphene. Furthermore, we show that Co migration in graphene is such that its <span class="hlt">magnetic</span> moment varies along the diffusion path. The <span class="hlt">magnetic</span> moment of Co is consistently higher in Co-DV diffusion when compared to that of Co-MV diffusion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011APS..DPPBP9096K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011APS..DPPBP9096K"><span id="translatedtitle">Validity of <span class="hlt">atomic</span> models for motional Stark effect diagnostic at low <span class="hlt">magnetic</span> fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ko, J.; den Hartog, D. J.; Caspary, K. J.; den Hartog, E. A.</p> <p>2011-10-01</p> <p>The motional Stark effect diagnostic for the MST reversed field pinch (RFP) deals with Stark spectra generated under low <span class="hlt">magnetic</span> fields (0.1 to 0.6 T). Therefore, its analysis, in principle, should rely on an <span class="hlt">atomic</span> model that includes spin-orbit coupling, Zeeman effects, and non-statistical populations of upper states in diagnostic-neutral-beam excitation. Currently, however, no <span class="hlt">atomic</span> model has been validated to be reliable for these low-field MSE spectra. A recent collisional radiative model [O Marchuk et al, J. Phys. B: At. Mol. Opt. Phys. 43 (2010) 011002] confirms that the observed Stark multiplets deviate from a statistical population, but calculation was done only at high fields (> 1 T). In this work, an operating window of MST RFP plasmas will be explored where a direct spectrum fit (that is, with no <span class="hlt">atomic</span> model involved) can produce reasonable <span class="hlt">magnetic</span> field measurements. The Stark intensities as well as the inferred <span class="hlt">magnetic</span> fields obtained this way will be compared with those from the existing <span class="hlt">atomic</span> models. Work supported by the USDoE.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatSR...618401Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatSR...618401Z"><span id="translatedtitle">Controlled Phase and Tunable <span class="hlt">Magnetism</span> in Ordered Iron Oxide Nanotube Arrays Prepared by <span class="hlt">Atomic</span> Layer Deposition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Yijun; Liu, Ming; Peng, Bin; Zhou, Ziyao; Chen, Xing; Yang, Shu-Ming; Jiang, Zhuang-De; Zhang, Jie; Ren, Wei; Ye, Zuo-Guang</p> <p>2016-01-01</p> <p>Highly-ordered and conformal iron oxide nanotube arrays on an <span class="hlt">atomic</span> scale are successfully prepared by <span class="hlt">atomic</span> layer deposition (ALD) with controlled oxidization states and tunable <span class="hlt">magnetic</span> properties between superparamagnetism and ferrimagnetism. Non-<span class="hlt">magnetic</span> α-Fe2O3 and superparamagnetic Fe3O4 with a blocking temperature of 120 K are in-situ obtained by finely controlling the oxidation reaction. Both of them exhibit a very small grain size of only several nanometers due to the nature of <span class="hlt">atom-by-atom</span> growth of the ALD technique. Post-annealing α-Fe2O3 in a reducing atmosphere leads to the formation of the spinel Fe3O4 phase which displays a distinct ferrimagnetic anisotropy and the Verwey metal-insulator transition that usually takes place only in single crystal magnetite or thick epitaxial films at low temperatures. The ALD deposition of iron oxide with well-controlled phase and tunable <span class="hlt">magnetism</span> demonstrated in this work provides a promising opportunity for the fabrication of 3D nano-devices to be used in catalysis, spintronics, microelectronics, data storages and bio-applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26813143','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26813143"><span id="translatedtitle">Controlled Phase and Tunable <span class="hlt">Magnetism</span> in Ordered Iron Oxide Nanotube Arrays Prepared by <span class="hlt">Atomic</span> Layer Deposition.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Yijun; Liu, Ming; Peng, Bin; Zhou, Ziyao; Chen, Xing; Yang, Shu-Ming; Jiang, Zhuang-De; Zhang, Jie; Ren, Wei; Ye, Zuo-Guang</p> <p>2016-01-01</p> <p>Highly-ordered and conformal iron oxide nanotube arrays on an <span class="hlt">atomic</span> scale are successfully prepared by <span class="hlt">atomic</span> layer deposition (ALD) with controlled oxidization states and tunable <span class="hlt">magnetic</span> properties between superparamagnetism and ferrimagnetism. Non-<span class="hlt">magnetic</span> α-Fe2O3 and superparamagnetic Fe3O4 with a blocking temperature of 120 K are in-situ obtained by finely controlling the oxidation reaction. Both of them exhibit a very small grain size of only several nanometers due to the nature of <span class="hlt">atom-by-atom</span> growth of the ALD technique. Post-annealing α-Fe2O3 in a reducing atmosphere leads to the formation of the spinel Fe3O4 phase which displays a distinct ferrimagnetic anisotropy and the Verwey metal-insulator transition that usually takes place only in single crystal magnetite or thick epitaxial films at low temperatures. The ALD deposition of iron oxide with well-controlled phase and tunable <span class="hlt">magnetism</span> demonstrated in this work provides a promising opportunity for the fabrication of 3D nano-devices to be used in catalysis, spintronics, microelectronics, data storages and bio-applications. PMID:26813143</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014IAUS..303...73G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014IAUS..303...73G"><span id="translatedtitle">The <span class="hlt">warm</span> ISM in the Sgr A region: mid-J CO, <span class="hlt">atomic</span> carbon, ionized <span class="hlt">atomic</span> carbon, and ionized nitrogen line observations with the Herschel/HIFI and NANTEN2/SMART Telescopes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Garca, Pablo; Simon, Robert; Stutzki, Jrgen; Requena-Torres, Miguel; Gsten, Rolf; Fukui, Yasuo; Yamamoto, Hiroaki; Bertoldi, Frank; Burton, Michael; Bronfman, Leonardo; Ogawa, Hideo</p> <p>2014-05-01</p> <p>We present Herschel/HIFI sub-mm <span class="hlt">atomic</span> carbon ([Ci] 3 P 1 - 3 P 0 and [Ci] 3 P 2 - 3 P 1), ionized carbon ([Cii] 2 P 3/2 - 2 P 1/2), and ionized nitrogen ([Nii] 3 P 1 - 3 P 0) line observations obtained in the frame of the Herschel Guaranteed Time HEXGAL (Herschel EXtraGALactic) key program (P. I. Rolf Gsten, MPIfR), and NANTEN2/SMART carbon monoxide (CO(J = 4 - 3)) observations of the <span class="hlt">warm</span> gas around the Sgr A region. The spectrally resolved emission from all lines, and the corresponding line intensity ratios, show a very complex morphology. The determination of spatial and spectral (anti)correlation with known sources in the Sgr A region such as the Arched Filaments, NTF filaments, the Sickle, Quintuplet cluster, CND clouds, is ongoing work.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26273981','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26273981"><span id="translatedtitle"><span class="hlt">Magnetic</span> Properties of Polycrystalline Bismuth Ferrite Thin Films Grown by <span class="hlt">Atomic</span> Layer Deposition.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jalkanen, Pasi; Tuboltsev, Vladimir; Marchand, Benoît; Savin, Alexander; Puttaswamy, Manjunath; Vehkamäki, Marko; Mizohata, Kenichiro; Kemell, Marianna; Hatanpää, Timo; Rogozin, Valentin; Räisänen, Jyrki; Ritala, Mikko; Leskelä, Markku</p> <p>2014-12-18</p> <p>The <span class="hlt">atomic</span> layer deposition (ALD) method was applied to grow thin polycrystalline BiFeO3 (BFO) films on Pt/SiO2/Si substrates. The 50 nm thick films were found to exhibit high resistivity, good morphological integrity, and homogeneity achieved by the applied ALD technique. <span class="hlt">Magnetic</span> characterization revealed saturated <span class="hlt">magnetization</span> of 25 emu/cm(3) with temperature-dependent coercivity varying from 5 to 530 Oe within the temperature range from 300 to 2 K. <span class="hlt">Magnetism</span> observed in the films was found to change gradually from ferromagnetic spin ordering to pinned <span class="hlt">magnetic</span> domain interactions mixed with weak spin-glass-like behavior of <span class="hlt">magnetically</span> frustrated antiferromagnetic/ferromagnetic (AFM-FM) spin ordering depending on the temperature and magnitude of the applied <span class="hlt">magnetic</span> field. Antiferromagnetic order of spin cycloids was broken in polycrystalline films by crystal sizes smaller than the cycloid length (∼60 nm). Uncompensated spincycloids and <span class="hlt">magnetic</span> domain walls were found to be the cause of the high <span class="hlt">magnetization</span> of the BFO films. PMID:26273981</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..MARS30011N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..MARS30011N"><span id="translatedtitle">Lattice Monte Carlo Simulation Study <span class="hlt">Atomic</span> Structure of Alnico 5-7 Permanent <span class="hlt">Magnets</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nguyen, Manh Cuong; Zhao, Xin; Wang, Cai-Zhuang; Ho, Kai-Ming</p> <p>2015-03-01</p> <p>The fluctuations and increases in price and the issues in supply recently of rare earth metals re-heated the sought for non-rare earth permanent <span class="hlt">magnets</span>. Alnico permanent <span class="hlt">magnets</span> have been considered as promising replacements for rare earth-based permanent <span class="hlt">magnets</span> due to the superiors in the <span class="hlt">magnetic</span> performance at high temperature and the abundances of the constituent elements. Using lattice Monte Carlo simulation in combination with cluster expansion method we study the <span class="hlt">atomic</span> structure of alnico 5-7 permanent <span class="hlt">magnets</span>. We observed the phase separation into FeCo-rich and NiAl-rich phases in alnico 5-7 at low temperature, which is consistent with experiment. The phase boundary between these two phases is quite sharp. Both FeCo-rich and NiAl-rich phases are in B2 ordering with Fe and Al sitting on ?-site and Ni and Co sitting on ?-site. The degree of order of NiAl-rich phase is quite higher than that of FeCo-rich phase and it decreases with temperature slower than that of FeCo-rich phase. We also observed a small and increasing with annealing temperature <span class="hlt">magnetic</span> moment in NiAl-rich phase, implying that the <span class="hlt">magnetic</span> properties of alnico 5-7 could be improved by lowering annealing temperature to diminish the <span class="hlt">magnetism</span> in NiAl-rich phase.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3389787','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3389787"><span id="translatedtitle"><span class="hlt">Magnetic</span> Relaxometry with an <span class="hlt">Atomic</span> Magnetometer and SQUID Sensors on Targeted Cancer Cells</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Johnson, Cort; Adolphi, Natalie L.; Butler, Kimberly L.; Debbie M, Lovato; Larson, Richard; Schwindt, Peter D.D.; Flynn, Edward R.</p> <p>2012-01-01</p> <p><span class="hlt">Magnetic</span> relaxometry methods have been shown to be very sensitive in detecting cancer cells and other targeted diseases. Superconducting Quantum Interference Device (SQUID) sensors are one of the primary sensor systems used in this methodology because of their high sensitivity with demonstrated capabilities of detecting fewer than 100,000 <span class="hlt">magnetically</span>-labeled cancer cells. The emerging technology of <span class="hlt">atomic</span> magnetometers (AM) represents a new detection method for <span class="hlt">magnetic</span> relaxometry with high sensitivity and without the requirement for cryogens. We report here on a study of <span class="hlt">magnetic</span> relaxometry using both AM and SQUID sensors to detect cancer cells that are coated with superparamagnetic nanoparticles through antibody targeting. The AM studies conform closely to SQUID sensor results in the measurement of the <span class="hlt">magnetic</span> decay characteristics following a <span class="hlt">magnetization</span> pulse. The AM and SQUID sensor data are well described theoretically for superparamagnetic particles bound to cells and the results can be used to determine the number of cells in a cell culture or tumor. The observed fields and <span class="hlt">magnetic</span> moments of cancer cells are linear with the number of cells over a very large range. The AM sensor demonstrates very high sensitivity for detecting <span class="hlt">magnetically</span> labeled cells does not require cryogenic cooling and is relatively inexpensive. PMID:22773885</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvL.115s3002S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvL.115s3002S"><span id="translatedtitle">Inducing Resonant Interactions in Ultracold <span class="hlt">Atoms</span> with a Modulated <span class="hlt">Magnetic</span> Field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smith, D. Hudson</p> <p>2015-11-01</p> <p>In systems of ultracold <span class="hlt">atoms</span>, pairwise interactions can be resonantly enhanced by a new mechanism that does not rely upon a <span class="hlt">magnetic</span> Feshbach resonance. In this mechanism, interactions are controlled by tuning the frequency of an oscillating parallel component of the <span class="hlt">magnetic</span> field close to the transition frequency between the scattering <span class="hlt">atoms</span> and a two-<span class="hlt">atom</span> bound state. The real part of the resulting s -wave scattering length a is resonantly enhanced when the oscillation frequency is close to the transition frequency. The resonance parameters can be controlled by varying the amplitude of the oscillating field. The amplitude also controls the imaginary part of a , which arises because the oscillating field converts <span class="hlt">atom</span> pairs into molecules. The real part of a can be made much larger than the background scattering length without introducing catastrophic <span class="hlt">atom</span> losses from the imaginary part. For the case of a shallow bound state in the scattering channel, the dimensionless resonance parameters are universal functions of the dimensionless oscillation amplitude.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24201042','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24201042"><span id="translatedtitle"><span class="hlt">Magnetic</span> field and <span class="hlt">atomic</span> order effect on the martensitic transformation of a metamagnetic alloy.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Barandiaran, J M; Chernenko, V A; Cesari, E; Salas, D; Gutierrez, J; Lazpita, P</p> <p>2013-12-01</p> <p>The martensitic transformation (MT) of metamagnetic shape memory alloys is very sensitive to the applied <span class="hlt">magnetic</span> field and <span class="hlt">atomic</span> order. We analyze the alloy Ni50Mn34.5In15.5 in <span class="hlt">magnetic</span> fields up to 13 T. The alloy has been prepared both in an ordered state by slow cooling, and in a disordered state by rapid quenching. In both cases the dependence of the martensitic transition temperature on the field is highly nonlinear. Such departure from linearity is due to a decrease of the entropy change at the transition, ΔS, with the applied field. This can be explained by the ordering effect of the <span class="hlt">magnetic</span> field on the frustrated <span class="hlt">magnetic</span> structure of the alloy in the martensitic phase. Compliance with a recent model, relying on the strong magnetoelastic interactions in these compounds, is very satisfactory. PMID:24201042</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1087049','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1087049"><span id="translatedtitle">Giant <span class="hlt">atomic</span> displacement at a <span class="hlt">magnetic</span> phase transition in metastable Mn3O4</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hirai, Shigeto; Moreira Dos Santos, Antonio F; Shapiro, Max C; Molaison, Jamie J; Pradhan, Neelam; Guthrie, Malcolm; Tulk, Christopher A; Fisher, Ian R; Mao, Wendy</p> <p>2013-01-01</p> <p>We present x-ray, neutron scattering, and heat capacity data that reveal a coupled first-order <span class="hlt">magnetic</span> and structural phase transition of the metastable mixed-valence postspinel compound Mn3O4 at 210 K. Powder neutron diffraction measurements reveal a <span class="hlt">magnetic</span> structure in which Mn3+ spins align antiferromagnetically along the edge-sharing a axis, with a <span class="hlt">magnetic</span> propagation vector k = [1/2,0,0]. In contrast, the Mn2+ spins, which are geometrically frustrated, do not order until a much lower temperature. Although the Mn2+ spins do not directly participate in the <span class="hlt">magnetic</span> phase transition at 210 K, structural refinements reveal a large <span class="hlt">atomic</span> shift at this phase transition, corresponding to a physical motion of approximately 0.25 angstrom, even though the crystal symmetry remains unchanged. This "giant" response is due to the coupled effect of built-in strain in the metastable postspinel structure with the orbital realignment of the Mn3+ ion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1234461-new-alnico-magnets-fabricated-from-pre-alloyed-gas-atomized-powder-through-diverse-consolidation-techniques','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1234461-new-alnico-magnets-fabricated-from-pre-alloyed-gas-atomized-powder-through-diverse-consolidation-techniques"><span id="translatedtitle">New alnico <span class="hlt">magnets</span> fabricated from pre-alloyed gas-<span class="hlt">atomized</span> powder through diverse consolidation techniques</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Tang, W.; Zhou, L.; Kassen, A. G.; Palasyuk, A.; White, E. M.; Dennis, K. W.; Kramer, M. J.; McCallum, R. W.; Anderson, I. E.</p> <p>2015-05-25</p> <p>Fine Alnico 8 spherical powder produced by gas <span class="hlt">atomization</span> was consolidated through hot pressing (HP), hot isostatic pressing (HIP), and compression molding and subsequent sintering (CMS) techniques. The effects of different fabrication techniques and processing parameters on microstructure and <span class="hlt">magnetic</span> properties were analyzed and compared. The HP, HIP, and CMS <span class="hlt">magnets</span> exhibited different features in microstructures and <span class="hlt">magnetic</span> properties. <span class="hlt">Magnetically</span> annealed at 840°C for 10 min and subsequently tempered at 650°C for 5h and 580°C for 15h, the HIP sample achieved the best coercivity (Hcj =1845 Oe) due to spinodally decomposed (SD) phases with uniform and well-faceted mosaic morphology. Asmore » a result, the CMS sample had a lower Hcj than HIP and HP samples, but a higher remanence and thus the best energy product (6.5 MGOe) due to preferential grain alignment induced by abnormal grain growth.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1234461','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1234461"><span id="translatedtitle">New alnico <span class="hlt">magnets</span> fabricated from pre-alloyed gas-<span class="hlt">atomized</span> powder through diverse consolidation techniques</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tang, W.; Zhou, L.; Kassen, A. G.; Palasyuk, A.; White, E. M.; Dennis, K. W.; Kramer, M. J.; McCallum, R. W.; Anderson, I. E.</p> <p>2015-05-25</p> <p>Fine Alnico 8 spherical powder produced by gas <span class="hlt">atomization</span> was consolidated through hot pressing (HP), hot isostatic pressing (HIP), and compression molding and subsequent sintering (CMS) techniques. The effects of different fabrication techniques and processing parameters on microstructure and <span class="hlt">magnetic</span> properties were analyzed and compared. The HP, HIP, and CMS <span class="hlt">magnets</span> exhibited different features in microstructures and <span class="hlt">magnetic</span> properties. <span class="hlt">Magnetically</span> annealed at 840°C for 10 min and subsequently tempered at 650°C for 5h and 580°C for 15h, the HIP sample achieved the best coercivity (H<sub>cj</sub> =1845 Oe) due to spinodally decomposed (SD) phases with uniform and well-faceted mosaic morphology. As a result, the CMS sample had a lower Hcj than HIP and HP samples, but a higher remanence and thus the best energy product (6.5 MGOe) due to preferential grain alignment induced by abnormal grain growth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22218237','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22218237"><span id="translatedtitle">Conductance of ferro- and antiferro-<span class="hlt">magnetic</span> single-<span class="hlt">atom</span> contacts: A first-principles study</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tan, Zhi-Yun; Zheng, Xiao-long; Ye, Xiang; Xie, Yi-qun; Ke, San-Huang</p> <p>2013-08-14</p> <p>We present a first-principles study on the spin dependent conductance of five single-<span class="hlt">atom</span> <span class="hlt">magnetic</span> junctions consisting of a <span class="hlt">magnetic</span> tip and an adatom adsorbed on a <span class="hlt">magnetic</span> surface, i.e., the Co-Co/Co(001) and Ni-X/Ni(001) (X = Fe, Co, Ni, Cu) junctions. When their spin configuration changes from ferromagnetism to anti-ferromagnetism, the spin-up conductance increases while the spin-down one decreases. For the junctions with a <span class="hlt">magnetic</span> adatom, there is nearly no spin valve effect as the decreased spin-down conductance counteracts the increased spin-up one. For the junction with a nonmagnetic adatom (Ni-Cu/Ni(001)), a spin valve effect is obtained with a variation of 22% in the total conductance. In addition, the change in spin configuration enhances the spin filter effect for the Ni-Fe/Ni(001) junction but suppresses it for the other junctions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3739803','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3739803"><span id="translatedtitle"><span class="hlt">Magnetic</span>-resonance imaging of the human brain with an <span class="hlt">atomic</span> magnetometer</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Savukov, I.; Karaulanov, T.</p> <p>2013-01-01</p> <p><span class="hlt">Magnetic</span> resonance imaging (MRI) is conventionally performed in very high fields, and this leads to some restrictions in applications. To remove such restrictions, the ultra-low field MRI approach has been proposed. Because of the loss of sensitivity, the detection methods based on superconducting quantum interference devices (SQUIDs) in a shielded room were used. <span class="hlt">Atomic</span> magnetometers have similar sensitivity as SQUIDs and can also be used for MRI, but there are some technical difficulties to overcome. We demonstrate that MRI of the human brain can be obtained with an <span class="hlt">atomic</span> magnetometer with in-plane resolution of 3?mm in 13?min. PMID:23964134</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PhRvL.107u3001M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PhRvL.107u3001M"><span id="translatedtitle"><span class="hlt">Magnetic</span> Dichroism in K-Shell Photoemission from Laser Excited Li <span class="hlt">Atoms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meyer, M.; Grum-Grzhimailo, A. N.; Cubaynes, D.; Felfli, Z.; Heinecke, E.; Manson, S. T.; Zimmermann, P.</p> <p>2011-11-01</p> <p><span class="hlt">Magnetic</span> dichroism in the angular distribution has been demonstrated for single-electron photoemission from inner ns2 subshells of gaseous <span class="hlt">atomic</span> targets using the example of K-shell photoionization of polarized Li <span class="hlt">atoms</span> laser prepared in the 1s22p P3/22 excited state. The effect is pronounced for the conjugate shakeup and conjugate shakedown photoelectron lines, and less important, though observable, for the main and direct shakeup lines. The phenomenon is caused by configuration interaction in the final continuum state and is quantitatively described by the close-coupling R-matrix calculations.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ApPhL.103d3703S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ApPhL.103d3703S"><span id="translatedtitle"><span class="hlt">Magnetic</span>-resonance imaging of the human brain with an <span class="hlt">atomic</span> magnetometer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Savukov, I.; Karaulanov, T.</p> <p>2013-07-01</p> <p><span class="hlt">Magnetic</span> resonance imaging (MRI) is conventionally performed in very high fields, and this leads to some restrictions in applications. To remove such restrictions, the ultra-low field MRI approach has been proposed. Because of the loss of sensitivity, the detection methods based on superconducting quantum interference devices (SQUIDs) in a shielded room were used. <span class="hlt">Atomic</span> magnetometers have similar sensitivity as SQUIDs and can also be used for MRI, but there are some technical difficulties to overcome. We demonstrate that MRI of the human brain can be obtained with an <span class="hlt">atomic</span> magnetometer with in-plane resolution of 3 mm in 13 min.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvB..93a4410D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvB..93a4410D"><span id="translatedtitle"><span class="hlt">Magnetically</span> driven anisotropic structural changes in the <span class="hlt">atomic</span> laminate M n2GaC</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dahlqvist, M.; Ingason, A. S.; Alling, B.; Magnus, F.; Thore, A.; Petruhins, A.; Mockute, A.; Arnalds, U. B.; Sahlberg, M.; Hjrvarsson, B.; Abrikosov, I. A.; Rosen, J.</p> <p>2016-01-01</p> <p>Inherently layered <span class="hlt">magnetic</span> materials, such as <span class="hlt">magnetic</span> Mn +1A Xn (MAX) phases, offer an intriguing perspective for use in spintronics applications and as ideal model systems for fundamental studies of complex <span class="hlt">magnetic</span> phenomena. The MAX phase composition Mn+1A Xn consists of Mn +1Xn blocks separated by <span class="hlt">atomically</span> thin A -layers where M is a transition metal, A an A-group element, X refers to carbon and/or nitrogen, and n is typically 1, 2, or 3. Here, we show that the recently discovered <span class="hlt">magnetic</span> M n2GaC MAX phase displays structural changes linked to the <span class="hlt">magnetic</span> anisotropy, and a rich <span class="hlt">magnetic</span> phase diagram which can be manipulated through temperature and <span class="hlt">magnetic</span> field. Using first-principles calculations and Monte Carlo simulations, an essentially one-dimensional (1D) interlayer plethora of two-dimensioanl (2D) Mn-C-Mn trilayers with robust intralayer ferromagnetic spin coupling was revealed. The complex transitions between them were observed to induce <span class="hlt">magnetically</span> driven anisotropic structural changes. The <span class="hlt">magnetic</span> behavior as well as structural changes dependent on the temperature and applied <span class="hlt">magnetic</span> field are explained by the large number of low energy, i.e., close to degenerate, collinear and noncollinear spin configurations that become accessible to the system with a change in volume. These results indicate that the <span class="hlt">magnetic</span> state can be directly controlled by an applied pressure or through the introduction of stress and show promise for the use of M n2GaC MAX phases in future magnetoelectric and magnetocaloric applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhRvA..87d3419R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhRvA..87d3419R"><span id="translatedtitle">Peculiarities of the tunneling ionization of <span class="hlt">atoms</span> and ions in a <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rylyuk, V. M.</p> <p>2013-04-01</p> <p>We consider the tunneling ionization of an electron, bound by a zero-range potential and a constant <span class="hlt">magnetic</span> field, under the influence of a low-frequency monochromatic laser beam. An integral equation for the complex quasienergy is derived based upon the exact solution of the Schrdinger equation and the Green's function earlier obtained by Rylyuk and Ortner [Phys. Rev. A1050-294710.1103/PhysRevA.67.013414 67, 013414 (2003)] for an electron moving in an arbitrary electromagnetic wave and a constant <span class="hlt">magnetic</span> field. We show that accounting for an electron spin leads to drastic changes in ionization probability. For the case of a nonzero angle ??0 between an electromagnetic wave direction and the <span class="hlt">magnetic</span> field the ionization rate is shown to increase with the <span class="hlt">magnetic</span> field when the electron spin is taken into account. The expressions for the level shift and width and for the diamagnetic and the paramagnetic susceptibilities of the electron in a zero-range force field and a constant <span class="hlt">magnetic</span> field are found. In the case of ionization of neutral <span class="hlt">atoms</span> and positive ions, we also take into consideration the Coulomb interaction of the emerging electron with the <span class="hlt">atomic</span> or ionic core.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvB..92j0407G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvB..92j0407G"><span id="translatedtitle"><span class="hlt">Atomic</span>-scale detection of <span class="hlt">magnetic</span> impurity interactions in bulk semiconductors</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Geisler, Benjamin; Kratzer, Peter</p> <p>2015-09-01</p> <p>We demonstrate on the basis of ab initio simulations how passivated semiconductor surfaces can be exploited to study bulklike interaction properties and wave functions of <span class="hlt">magnetic</span> impurities on the <span class="hlt">atomic</span> scale with conventional and spin-polarized scanning tunneling microscopy. By applying our approach to the case of 3 d transition metal impurities close to the H /Si (111 ) surface, we show exemplarily that their wave functions in Si are less extended than for Mn in GaAs, thus obstructing ferromagnetism in Si. Finally, we discuss possible applications of this method to other dilute <span class="hlt">magnetic</span> semiconductors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21069852','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21069852"><span id="translatedtitle">Using coherent population trapping in test <span class="hlt">atoms</span> for <span class="hlt">magnetic</span> field measurements in toroidal plasmas</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Akhmedzhanov, R. A.; Gushchin, L. A.; Zelensky, I. V.; Litvak, A. G.; Tokman, M. D.</p> <p>2007-09-15</p> <p>A way to measure the profile of the safety factor in toroidal controlled-fusion setups has been developed. The method is based on measuring the ratio of the poloidal <span class="hlt">magnetic</span> field and the toroidal one locally, based on a modification of the optical resonance-fluorescence signal. The effect of partial suppression of resonance fluorescence is used, which depends on the orientation of the <span class="hlt">magnetic</span> field relative to the laser beam, and takes place in case of coherent population trapping in test <span class="hlt">atoms</span> with the Zeeman split-level structure, as affected by double-frequency laser radiation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/7256663','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/7256663"><span id="translatedtitle">Status of the BNL cold <span class="hlt">atomic</span> beam and its focusing <span class="hlt">magnets</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hershcovitch, A.; Kponou, A.; DeVito, B.</p> <p>1990-01-01</p> <p>Since the last workshop in Montana, Switzerland, output of the BNL cold <span class="hlt">atomic</span> beam has improved by more than an order of magnitude to a flux of over 10{sup 20} H{sup 0}/sr/s. Spin selection and focusing by three different <span class="hlt">magnets</span>: a superconducting solenoid lens, a long permanent <span class="hlt">magnet</span> sextupole, and a system consisting of two short permanent and electromagnet sextupoles, have been tried. Results indicate that the latter scheme is best for our particular needs. 6 refs., 1 fig., 1 tab.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1157610','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1157610"><span id="translatedtitle">Structural and <span class="hlt">Magnetic</span> Evolution of Bimetallic MnAu Clusters Driven by Asymmetric <span class="hlt">Atomic</span> Migration</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wei, Xiaohui; Zhou, Rulong; Lefebvre, Williams; He, Kai; Le Roy, Damien; Skomski, Ralph; Li, Xingzhong; Shield, Jeffrey E; Kramer, Matthew J; Chen, Shuang; Zeng, Xiao Cheng; Sellmyer, David J</p> <p>2014-03-12</p> <p>The nanoscale structural, compositional, and <span class="hlt">magnetic</span> properties are examined for annealed MnAu nanoclusters. The MnAu clusters order into the L10 structure, and monotonic size-dependences develop for the composition and lattice parameters, which are well reproduced by our density functional theory calculations. Simultaneously, Mn diffusion forms 5 Å nanoshells on larger clusters inducing significant <span class="hlt">magnetization</span> in an otherwise antiferromagnetic system. The differing <span class="hlt">atomic</span> mobilities yield new cluster nanostructures that can be employed generally to create novel physical properties.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhLA..380.1193H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhLA..380.1193H"><span id="translatedtitle">Characteristics of the resonant instability of surface electrostatic-ion-cyclotron waves in a semi-bounded <span class="hlt">warm</span> <span class="hlt">magnetized</span> dusty plasma</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hong, Woo-Pyo; Jung, Young-Dae</p> <p>2016-03-01</p> <p>The influence of <span class="hlt">magnetic</span> field and dust rotation on the resonant instability of surface electrostatic-ion-cyclotron wave is kinetically investigated in a semi-bounded <span class="hlt">warm</span> <span class="hlt">magnetized</span> dusty plasma. The dispersion relation and the temporal growth rate of the surface electrostatic-ion-cyclotron wave are derived by the specular-reflection boundary condition including the <span class="hlt">magnetic</span> field and dust rotation effects. It is found that the instability domain decreases with an increase of the rotation frequency of elongated dust grain. It is also found that the dependence of the propagation wave number on the temporal growth rate is more significant for small ion cyclotron frequencies. In addition, it is shown that the scaled growth rate increases with an increase of the strength of <span class="hlt">magnetic</span> field. The variation of the domain and magnitude of temporal growth rate due to the change of plasma parameters is also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DMP.C3010S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DMP.C3010S"><span id="translatedtitle">Inducing Resonant Interactions in Ultracold <span class="hlt">Atoms</span> with an Oscillating <span class="hlt">Magnetic</span> Field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smith, D. Hudson</p> <p>2015-05-01</p> <p>In systems of ultracold <span class="hlt">atoms</span>, two-<span class="hlt">atom</span> interactions can be resonantly enhanced by a new mechanism which does not rely upon the presence of a Feshbach resonance. In this mechanism, interactions are controlled by tuning the frequency of an applied oscillating <span class="hlt">magnetic</span> field near the Bohr frequency corresponding to the energy gap between a pair of low-energy <span class="hlt">atoms</span> and a two-<span class="hlt">atom</span> bound state. Near the resonance, the s-wave scattering length is a simple function of the oscillation frequency whose asymmetric line-shape is similar to that of Feshbach resonances. <span class="hlt">Atom</span> pairs can absorb (emit) quanta from (to) the oscillating field leading to inelastic losses. This mechanism for inducing resonant interactions is illustrated using two simple models, from which the dependencies of the resonance parameters on the strength of oscillating field are extracted. This mechanism gives experimental access to strongly interacting systems of <span class="hlt">atoms</span> that have no convenient Feshbach resonance. This research was supported by the National Science Foundation under grant PHY-1310862.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1213313-achieving-atomic-resolution-magnetic-dichroism-controlling-phase-symmetry-electron-probe','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1213313-achieving-atomic-resolution-magnetic-dichroism-controlling-phase-symmetry-electron-probe"><span id="translatedtitle">Achieving <span class="hlt">atomic</span> resolution <span class="hlt">magnetic</span> dichroism by controlling the phase symmetry of an electron probe</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Rusz, Jan; Idrobo, Juan -Carlos; Bhowmick, Somnath</p> <p>2014-09-30</p> <p>The calculations presented here reveal that an electron probe carrying orbital angular momentum is just a particular case of a wider class of electron beams that can be used to measure electron <span class="hlt">magnetic</span> circular dichroism (EMCD) with <span class="hlt">atomic</span> resolution. It is possible to obtain an EMCD signal with <span class="hlt">atomic</span> resolution by simply breaking the symmetry of the electron probe phase front using the aberration-corrected optics of a scanning transmission electron microscope. The probe’s required phase distribution depends on the sample’s <span class="hlt">magnetic</span> symmetry and crystal structure. The calculations indicate that EMCD signals that use the electron probe’s phase are as strongmore » as those obtained by nanodiffraction methods.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ASPC..494..261G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ASPC..494..261G"><span id="translatedtitle">Rydberg States of <span class="hlt">Atoms</span> and Molecules in the Atmospheres of Very Cool Stars with <span class="hlt">Magnetic</span> Fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gnedin, Yu. N.; Piotrovich, M. Yu.; Klyucharev, A. N.</p> <p>2015-04-01</p> <p>We present the results of observations of ultra cool active stars, including new discoveries and determination of spectral types from the SDSS and 2MASS photometric colors. A number of cool dwarfs emit circularly polarized radio waves generated by the electron cyclotron maser instability. Strong infrared absorption is observed in these stars. Model atmosphere calculations indicate that the pure hydrogen composition may be ruled out. The fundamental dipole-dipole interaction between the cold Rydberg <span class="hlt">atoms</span> is the dominant physical process in these stars. The Rydberg states exhibit unique phenomena, such as the spin polarization patterns and giant electric dipole moments induced by the <span class="hlt">magnetic</span> field. As a result, highly excited <span class="hlt">atoms</span> very sensitive to the electric and <span class="hlt">magnetic</span> fields can be used for the spectroscopic detection and compensation for the effects of these fields.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/467341','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/467341"><span id="translatedtitle">Hydrogen <span class="hlt">atom</span> in a <span class="hlt">magnetic</span> field: Ghost orbits, catastrophes, and uniform semiclassical approximations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Main, J.; Wunner, G.</p> <p>1997-03-01</p> <p>Applying closed-orbit theory to the recurrence spectra of the hydrogen <span class="hlt">atom</span> in a <span class="hlt">magnetic</span> field, one can interpret most, but not all, structures semiclassically in terms of closed classical orbits. In particular, conventional closed-orbit theory fails near bifurcations of orbits where semiclassical amplitudes exhibit unphysical divergences. Here we analyze the role of ghost orbits living in complex phase space. The ghosts can explain resonance structures in the spectra of the hydrogen <span class="hlt">atom</span> in a <span class="hlt">magnetic</span> field at positions where no real orbits exist. For three different types of catastrophes, viz. fold, cusp, and butterfly catastrophes, we construct uniform semiclassical approximations and demonstrate that these solutions are completely determined by classical parameters of the real orbits and complex ghosts. {copyright} {ital 1997} {ital The American Physical Society}</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26322964','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26322964"><span id="translatedtitle">Partial nitrogen <span class="hlt">atom</span> transfer: a new synthetic tool to design single-molecule <span class="hlt">magnets</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ding, Mei; Rouzires, Mathieu; Losovyj, Yaroslav; Pink, Maren; Clrac, Rodolphe; Smith, Jeremy M</p> <p>2015-09-21</p> <p>Incomplete nitrogen <span class="hlt">atom</span> transfer from the iron(IV) nitride complex PhB(MesIm)3Fe?N to the vanadium(III) complex V(Mes)3(THF) quantitatively provides the bimetallic complex PhB(MesIm)3Fe-N?V(Mes)3. Structural and spectroscopic characterizations reveal that the nitride ligand forms a linear bridge between V(V) and high-spin Fe(II) metal ions, confirming that <span class="hlt">atom</span> transfer is accompanied by electron transfer. In the presence of an applied dc field, the complex displays slow relaxation of the <span class="hlt">magnetization</span>, revealing its single-molecule <span class="hlt">magnet</span> properties with an estimation of the energy barrier at about 10 K. This complex establishes a synthetic principle for the assembly of paramagnetic complexes bridged by nitride ligands. PMID:26322964</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JChPh.144a4308F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JChPh.144a4308F"><span id="translatedtitle">Rotating effects on the Landau quantization for an <span class="hlt">atom</span> with a <span class="hlt">magnetic</span> quadrupole moment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fonseca, I. C.; Bakke, K.</p> <p>2016-01-01</p> <p>Based on the single particle approximation [Dmitriev et al., Phys. Rev. C 50, 2358 (1994) and C.-C. Chen, Phys. Rev. A 51, 2611 (1995)], the Landau quantization associated with an <span class="hlt">atom</span> with a <span class="hlt">magnetic</span> quadrupole moment is introduced, and then, rotating effects on this analogue of the Landau quantization is investigated. It is shown that rotating effects can modify the cyclotron frequency and breaks the degeneracy of the analogue of the Landau levels.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JPCM...26F2202G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JPCM...26F2202G"><span id="translatedtitle">Long range ordered <span class="hlt">magnetic</span> and <span class="hlt">atomic</span> structures of the quasicrystal approximant in the Tb-Au-Si system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gebresenbut, Girma; Svante Andersson, Mikael; Beran, P?emysl; Manuel, Pascal; Nordblad, Per; Sahlberg, Martin; Pay Gomez, Cesar</p> <p>2014-08-01</p> <p>The <span class="hlt">atomic</span> and <span class="hlt">magnetic</span> structure of the 1/1 Tb(14)Au(70)Si(16) quasicrystal approximant has been solved by combining x-ray and neutron diffraction data. The <span class="hlt">atomic</span> structure is classified as a Tsai-type 1/1 approximant with certain structural deviations from the prototype structures; there are additional <span class="hlt">atomic</span> positions in the so-called cubic interstices as well as in the cluster centers. The <span class="hlt">magnetic</span> property and neutron diffraction measurements indicate the <span class="hlt">magnetic</span> structure to be ferrimagnetic-like below 9 K in contrast to the related Gd(14)Au(70)Si(16) structure that is reported to be purely ferromagnetic.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21137965','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21137965"><span id="translatedtitle">The migration behavior of <span class="hlt">atomic</span> clusters in early nanocrystalline process of soft <span class="hlt">magnetic</span> Finemet alloy.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Yuxin; Li, Xiang; Zhang, Yu; Zhao, Guannan; Yan, Biao; Lu, Wei</p> <p>2010-11-01</p> <p>The Finemet alloys are commonly used as cores in transformers and generators, stress and field sensors in technological application for their excellent soft <span class="hlt">magnetic</span> characteristics. To clarify the nanocrystallization mechanism of Finemet especially about the <span class="hlt">atomic</span> migration in early stage is very essential for developing their distinctive characteristics. In this study, we investigate the migration behavior of <span class="hlt">atoms</span> in order to clarify the mechanism of the early-stage nanocrystallization in amorphous Finemet alloys. The Fe(73.5)Si(13.5)B9Nb3Cu1 amorphous ribbons were prepared by single-roller melt-spinning process in argon atmosphere, and then annealed at 350 degrees C-400 degrees C for 10 minutes in vacuum. The <span class="hlt">atom</span> force microscope (AFM) and the coincidence Doppler broadening spectra (CDB) were used to characterize the migration behavior of different <span class="hlt">atoms</span> in Fe(73.5)Si(13.5)B9Nb3Cu1 amorphous alloy during the early-stage nanocrystallization. The X-ray diffraction (XRD) patterns show that all annealed samples are in the amorphous state. But the AFM observation shows clearly that there are many small <span class="hlt">atomic</span> clusters (nuclei) which distribute in the amorphous matrix of the annealed samples. With increasing annealing temperature, there is a significant increase in the amount of <span class="hlt">atomic</span> clusters and a dramatic drop in the average size of clusters with very limited Cu contention in the samples, which reflect the structural evolution into more homogeneity. The CDB spectrum indicates that the peaks of positron annihilation spectrum are gradually reduced, which means the number of grain boundary and the defects in samples are gradually increased. It can be concluded that more defects are introduced by the formation of <span class="hlt">atomic</span> clusters through <span class="hlt">atomic</span> migration during the early-stage nanocrystallization in Fe(73.5)Si(13.5)B9Nb3Cu1 amorphous alloys. PMID:21137965</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9652E..09M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9652E..09M"><span id="translatedtitle"><span class="hlt">Magnetic</span> induction imaging with optical <span class="hlt">atomic</span> magnetometers: towards applications to screening and surveillance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Marmugi, Luca; Hussain, Sarah; Deans, Cameron; Renzoni, Ferruccio</p> <p>2015-10-01</p> <p>We propose a new approach, based on optical <span class="hlt">atomic</span> magnetometers and <span class="hlt">magnetic</span> induction tomography (MIT), for remote and non-invasive detection of conductive targets. <span class="hlt">Atomic</span> magnetometers overcome the main limitations of conventional MIT instrumentation, in particular their poor low-frequency sensitivity, their large size and their limited scalability. Moreover, <span class="hlt">atomic</span> magnetometers have been proven to reach extremely high sensitivities, with an improvement of up to 7 orders of magnitude in the 50 MHz to DC band, with respect to a standard pick-up coil of the same size. In the present scheme, an oscillating <span class="hlt">magnetic</span> field induces eddy currents in a conductive target and laser-pumped <span class="hlt">atomic</span> magnetometers, either stand-alone or in an array, detect the response of the objects. A phase-sensitive detection scheme rejects the background, allowing remote detection of the secondary field and, thus, mapping of objects, hidden in cargos, underwater or underground. The potential for extreme sensitivity, miniaturization, dynamic range and array operation paves the way to a new generation of non-invasive, active detectors for surveillance, as well as for real-time cargo screening.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E1647K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E1647K"><span id="translatedtitle"><span class="hlt">Atomic</span> scale study of <span class="hlt">magnetic</span> phase transitions in (Co,Ti;Sc) substituted nanosize barium hexaferrite</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Krezhov, Kiril</p> <p></p> <p>BaFe12O19 and related isostructural (M-type) hexaferrites derived by single or double cation substitution for Fe3+ with preservation of the formal valence are a recognized group of oxides for their remarkable properties. The <span class="hlt">magnetic</span> interactions may be tuned by suitable substitutions resulting in notable <span class="hlt">magnetic</span> properties utilized extensively for permanent <span class="hlt">magnets</span>, microwave devices and perpendicular recording media. We report on the <span class="hlt">magnetic</span> structure evolution accompanying the <span class="hlt">magnetic</span> anisotropy change, from a combined <span class="hlt">magnetic</span> (SQUID), x-ray and neutron diffraction, and <span class="hlt">magnetic</span> field dependent 57Fe Mössbauer study on BaFe12O19 at selected cation substitutions. The short and long range <span class="hlt">atomic</span> and <span class="hlt">magnetic</span> order in powder samples of nanosize particles prepared by soft chemistry routes were studied and compared with own and literature data for the parent BaFe12O19 compound prepared by solid state reaction. Refinements based on diffraction data show that the <span class="hlt">magnetic</span> structures of BaFe12-xXxO19 (X=Co,Ti; Sc) hexaferrites are largely temperature and substitution dependent. Between 200 and 300K the (Co,Ti)-hexaferrites (x=0.4, 0.7, 0.8, 0.85) display ferrimagnetic structures where the canting of the <span class="hlt">magnetic</span> moments depends on the substitution rate. When lowering the temperature the <span class="hlt">magnetic</span> structure for x=0.45 remains ferrimagnetic down to 10 K, while for x=0.7 and x=0.8 a complex conical <span class="hlt">magnetic</span> structures is finally established. For x=0.85 significant distortions in the local oxygen surrounding of ferric cation sites were established, while the grain-size effect on the structural parameters was considerably smaller. The thermal expansion coefficient exhibits a strong anisotropy. The refined <span class="hlt">magnetic</span> moments are considerably lower than the theoretical spin only moments, especially for the 4e and 12k sites, indicating a local noncollinearity with short-range ordering. The five-cation sublattice collinear ferrimagnetic structure of uniaxial type known as Gorter type for BaFe12O19 remains effective also for BaFe10.4Sc1.6O19 at room temperature and below it down to about 190 K. Below 190 K it gradually transforms into a complex canted structure with spins pointing out of the axial direction so that at 10 K the complex arrangement of <span class="hlt">magnetic</span> moments could be described in terms of an incommensurate complex block-type conical structure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvB..93f4407K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvB..93f4407K"><span id="translatedtitle">High-frequency <span class="hlt">magnetization</span> dynamics of individual <span class="hlt">atomic</span>-scale <span class="hlt">magnets</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Krause, S.; Sonntag, A.; Hermenau, J.; Friedlein, J.; Wiesendanger, R.</p> <p>2016-02-01</p> <p>The <span class="hlt">magnetization</span> dynamics of individual nanomagnets is studied by spin-polarized scanning tunneling microscopy, combining real-time telegraphic noise analysis with pump-probe schemes. A transition between two Arrhenius regimes is observed as a function of temperature. The switching rates at high temperature are found to be orders of magnitude lower than expected from the extrapolation from the low-temperature regime. A four-state hopping model of <span class="hlt">magnetization</span> reversal is developed to interpret the experimental results in terms of nucleation, annihilation, and propagation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008JAP...103gE511Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008JAP...103gE511Y"><span id="translatedtitle"><span class="hlt">Magnetic</span> and <span class="hlt">atomic</span> structure parameters of Sc-doped barium hexagonal ferrites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Aria; Chen, Yajie; Chen, Zhaohui; Vittoria, Carmine; Harris, V. G.</p> <p>2008-04-01</p> <p>Scandium-doped M-type barium hexagonal ferrites of the composition BaFe12-xScxO19 are well suited for low frequency microwave device applications such as isolators and circulators. A series of Sc-doped M-type barium hexagonal ferrite powders (x =0-1.2) were prepared by conventional ceramic processing techniques. The resulting powders were verified to be pure phase and maintain the nominal chemical stoichiometry by x-ray diffraction and energy dispersive x-ray spectroscopy, respectively. Static <span class="hlt">magnetic</span> measurements indicated that both saturation <span class="hlt">magnetization</span> and uniaxial magnetocrystalline anisotropy field decreased with increasing concentration of scandium. Extended x-ray absorption fine structure measurements were carried out to clarify the correlation between the <span class="hlt">magnetic</span> and <span class="hlt">atomic</span> structure properties. It is found that the substituted Sc has a strong preference for the bipyramidal site. Nevertheless, the substitution did not introduce additional <span class="hlt">atomic</span> structural disorder into the barium hexagonal structure. The structural study provided important evidence to quantitatively explain the change in dc and microwave <span class="hlt">magnetic</span> properties due to Sc ion doping.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21451131','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21451131"><span id="translatedtitle">THE IMPRINT OF THE VERY LOCAL INTERSTELLAR <span class="hlt">MAGNETIC</span> FIELD IN SIMULATED ENERGETIC NEUTRAL <span class="hlt">ATOM</span> MAPS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Prested, C.; Schwadron, N.; Opher, M. E-mail: nathanas@bu.ed</p> <p>2010-06-10</p> <p>The interaction of the solar wind with the very local interstellar medium (VLISM) forms the boundaries of the heliosphere. A strong asymmetry of the heliosphere was found both directly by the Voyager probes and indirectly from measurements of the deflection of neutral hydrogen. The most likely source of this asymmetry is from the interstellar <span class="hlt">magnetic</span> field, the properties of which are highly unconstrained. Energetic neutral <span class="hlt">atom</span> (ENA) images will provide an additional method to view the heliosphere and infer the interstellar <span class="hlt">magnetic</span> field. This paper investigates the imprint of the interstellar <span class="hlt">magnetic</span> field on simulated energetic neutral <span class="hlt">atom</span> all-sky maps. We show that a significant source of 0.5-1 keV ENAs may originate from the outside of the heliopause, if a strong suprathermal population exists in the VLISM. In simulations, a strong outer heliosheath ENA feature appears near the nose of the heliosphere. A weaker, complementary feature is also present consisting entirely of inner heliosheath ENAs. From this feature the direction of the interstellar <span class="hlt">magnetic</span> field can be easily inferred.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/959702','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/959702"><span id="translatedtitle"><span class="hlt">Magnetic</span> and <span class="hlt">Atomic</span> Structure Parameters of Sc-doped Barium Hexagonal Ferrites</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yang,A.; Chen, Y.; Chen, Z.; Vittoria, C.; Harris, V.</p> <p>2008-01-01</p> <p>Scandium-doped M-type barium hexagonal ferrites of the composition BaFe12?xScxO19 are well suited for low frequency microwave device applications such as isolators and circulators. A series of Sc-doped M-type barium hexagonal ferrite powders (x = 0-1.2) were prepared by conventional ceramic processing techniques. The resulting powders were verified to be pure phase and maintain the nominal chemical stoichiometry by x-ray diffraction and energy dispersive x-ray spectroscopy, respectively. Static <span class="hlt">magnetic</span> measurements indicated that both saturation <span class="hlt">magnetization</span> and uniaxial magnetocrystalline anisotropy field decreased with increasing concentration of scandium. Extended x-ray absorption fine structure measurements were carried out to clarify the correlation between the <span class="hlt">magnetic</span> and <span class="hlt">atomic</span> structure properties. It is found that the substituted Sc has a strong preference for the bipyramidal site. Nevertheless, the substitution did not introduce additional <span class="hlt">atomic</span> structural disorder into the barium hexagonal structure. The structural study provided important evidence to quantitatively explain the change in dc and microwave <span class="hlt">magnetic</span> properties due to Sc ion doping.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MNRAS.457...74S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MNRAS.457...74S"><span id="translatedtitle">Time-dependent <span class="hlt">atomic</span> diffusion in <span class="hlt">magnetic</span> ApBp stars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stift, M. J.; Alecian, G.</p> <p>2016-03-01</p> <p>Numerical modelling of surface abundance distributions in ApBp star atmospheres constitutes a challenging astrophysical problem. This paper is intended to deepen our understanding of how <span class="hlt">atomic</span> diffusion affects the atmospheric structure of <span class="hlt">magnetic</span> ApBp stars, and in particular how time-dependent calculations may be compared to the alternative method of estimating equilibrium stratifications. Our numerical calculations - with the stellar atmosphere adjusted self-consistently to the abundance profiles - show that final stationary solutions of the time-dependent diffusion problem (constant particle flux throughout the stellar atmosphere) are seemingly at variance with equilibrium stratifications (zero particle flux). In this work, we will provide some understanding of the origin of these differences and try to elucidate the as yet little explored behaviour of time-dependent <span class="hlt">atomic</span> diffusion. To this purpose, we assess the influence of the boundary condition at the bottom of the atmosphere, we investigate how the stratifications depend on <span class="hlt">magnetic</span> field angle and strength, and we have a look at possible interactions between different chemical elements. Based on a grid of atmospheric models and stratifications reflecting dipolar <span class="hlt">magnetic</span> geometries, we also present predicted line profiles for different oblique rotator models. Finally, we shortly discuss the consequences of our findings for the interpretation of abundance maps of <span class="hlt">magnetic</span> ApBp stars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatSR...618983L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatSR...618983L"><span id="translatedtitle">Tunable <span class="hlt">atomic</span> spin-orbit coupling synthesized with a modulating gradient <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Luo, Xinyu; Wu, Lingna; Chen, Jiyao; Guan, Qing; Gao, Kuiyi; Xu, Zhi-Fang; You, L.; Wang, Ruquan</p> <p>2016-01-01</p> <p>We report the observation of synthesized spin-orbit coupling (SOC) for ultracold spin-1 87Rb <span class="hlt">atoms</span>. Different from earlier experiments where a one dimensional (1D) <span class="hlt">atomic</span> SOC of pseudo-spin-1/2 is synthesized with Raman laser fields, the scheme we demonstrate employs a gradient <span class="hlt">magnetic</span> field (GMF) and ground-state <span class="hlt">atoms</span>, thus is immune to <span class="hlt">atomic</span> spontaneous emission. The strength of SOC we realize can be tuned by changing the modulation amplitude of the GMF, and the effect of the SOC is confirmed through the studies of: 1) the collective dipole oscillation of an <span class="hlt">atomic</span> condensate in a harmonic trap after the synthesized SOC is abruptly turned on; and 2) the minimum energy state at a finite adiabatically adjusted momentum when SOC strength is slowly ramped up. The condensate coherence is found to remain very good after driven by modulating GMFs. Our scheme presents an alternative means for studying interacting many-body systems with synthesized SOC.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26752786','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26752786"><span id="translatedtitle">Tunable <span class="hlt">atomic</span> spin-orbit coupling synthesized with a modulating gradient <span class="hlt">magnetic</span> field.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Luo, Xinyu; Wu, Lingna; Chen, Jiyao; Guan, Qing; Gao, Kuiyi; Xu, Zhi-Fang; You, L; Wang, Ruquan</p> <p>2016-01-01</p> <p>We report the observation of synthesized spin-orbit coupling (SOC) for ultracold spin-1 (87)Rb <span class="hlt">atoms</span>. Different from earlier experiments where a one dimensional (1D) <span class="hlt">atomic</span> SOC of pseudo-spin-1/2 is synthesized with Raman laser fields, the scheme we demonstrate employs a gradient <span class="hlt">magnetic</span> field (GMF) and ground-state <span class="hlt">atoms</span>, thus is immune to <span class="hlt">atomic</span> spontaneous emission. The strength of SOC we realize can be tuned by changing the modulation amplitude of the GMF, and the effect of the SOC is confirmed through the studies of: 1) the collective dipole oscillation of an <span class="hlt">atomic</span> condensate in a harmonic trap after the synthesized SOC is abruptly turned on; and 2) the minimum energy state at a finite adiabatically adjusted momentum when SOC strength is slowly ramped up. The condensate coherence is found to remain very good after driven by modulating GMFs. Our scheme presents an alternative means for studying interacting many-body systems with synthesized SOC. PMID:26752786</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4707438','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4707438"><span id="translatedtitle">Tunable <span class="hlt">atomic</span> spin-orbit coupling synthesized with a modulating gradient <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Luo, Xinyu; Wu, Lingna; Chen, Jiyao; Guan, Qing; Gao, Kuiyi; Xu, Zhi-Fang; You, L.; Wang, Ruquan</p> <p>2016-01-01</p> <p>We report the observation of synthesized spin-orbit coupling (SOC) for ultracold spin-1 87Rb <span class="hlt">atoms</span>. Different from earlier experiments where a one dimensional (1D) <span class="hlt">atomic</span> SOC of pseudo-spin-1/2 is synthesized with Raman laser fields, the scheme we demonstrate employs a gradient <span class="hlt">magnetic</span> field (GMF) and ground-state <span class="hlt">atoms</span>, thus is immune to <span class="hlt">atomic</span> spontaneous emission. The strength of SOC we realize can be tuned by changing the modulation amplitude of the GMF, and the effect of the SOC is confirmed through the studies of: 1) the collective dipole oscillation of an <span class="hlt">atomic</span> condensate in a harmonic trap after the synthesized SOC is abruptly turned on; and 2) the minimum energy state at a finite adiabatically adjusted momentum when SOC strength is slowly ramped up. The condensate coherence is found to remain very good after driven by modulating GMFs. Our scheme presents an alternative means for studying interacting many-body systems with synthesized SOC. PMID:26752786</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Global+AND+warming+AND+pollution&pg=3&id=EJ391198','ERIC'); return false;" href="http://eric.ed.gov/?q=Global+AND+warming+AND+pollution&pg=3&id=EJ391198"><span id="translatedtitle">Global <span class="hlt">Warming</span>.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Hileman, Bette</p> <p>1989-01-01</p> <p>States the foundations of the theory of global <span class="hlt">warming</span>. Describes methodologies used to measure the changes in the atmosphere. Discusses steps currently being taken in the United States and the world to slow the <span class="hlt">warming</span> trend. Recognizes many sources for the <span class="hlt">warming</span> and the possible effects on the earth. (MVL)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=388670','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=388670"><span id="translatedtitle"><span class="hlt">Atomic</span> Regime in Which the <span class="hlt">Magnetic</span> Interaction Dominates the Coulomb Interaction for Highly Excited States of Hydrogen</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Mueller, Ronald O.; Hughes, Vernon W.</p> <p>1974-01-01</p> <p>The <span class="hlt">atomic</span> regime in which the interaction of the electron with an external <span class="hlt">magnetic</span> field dominates the Coulomb interaction with the nucleus, relevant to pulsars, can be realized at laboratory <span class="hlt">magnetic</span> fields for discrete autoionized states of hydrogen, at energies above the ionization limit. Approximate wave functions, energy levels, and electric dipole transition probabilities are presented for hydrogen, and an <span class="hlt">atomic</span> beam absorption spectroscopy experiment at 50 kG is proposed to study this new regime. PMID:16578723</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20787527','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20787527"><span id="translatedtitle">Resonant electric dipole-dipole interactions between cold Rydberg <span class="hlt">atoms</span> in a <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Afrousheh, K.; Bohlouli-Zanjani, P.; Carter, J. D.; Mugford, A.; Martin, J. D. D.</p> <p>2006-06-15</p> <p>Laser-cooled {sup 85}Rb <span class="hlt">atoms</span> were optically excited to 46d{sub 5/2} Rydberg states. A microwave pulse transferred a fraction of the <span class="hlt">atoms</span> to the 47p{sub 3/2} Rydberg state. The resonant electric dipole-dipole interactions between <span class="hlt">atoms</span> in these two states were probed using the linewidth of the two-photon microwave transition 46d{sub 5/2}-47d{sub 5/2}. The presence of a weak <span class="hlt">magnetic</span> field {approx_equal}0.5 G reduced the observed line broadening, indicating that the interaction is suppressed by the field. The field removes some of the energy degeneracies responsible for the resonant interaction, and this is the basis for a quantitative model of the resulting suppression. A technique for the calibration of <span class="hlt">magnetic</span> field strengths using the 34s{sub 1/2}-34p{sub 1/2} one-photon transition is also presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1227396','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1227396"><span id="translatedtitle">Electric and <span class="hlt">magnetic</span> response in dielectric dark states for low loss subwavelength optical meta <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jain, Aditya; Moitra, Parikshit; Koschny, Thomas; Valentine, Jason; Soukoulis, Costas M.</p> <p>2015-07-14</p> <p>Artificially created surfaces or metasurfaces, composed of appropriately shaped subwavelength structures, namely, meta-<span class="hlt">atoms</span>, control light at subwavelength scales. Historically, metasurfaces have used radiating metallic resonators as subwavelength inclusions. However, while resonant optical metasurfaces made from metal have been sufficiently subwavelength in the propagation direction, they are too lossy for many applications. Metasurfaces made out of radiating dielectric resonators have been proposed to solve the loss problem, but are marginally subwavelength at optical frequencies. We designed subwavelength resonators made out of nonradiating dielectrics. The resonators are decorated with appropriately placed scatterers, resulting in a meta-<span class="hlt">atom</span> with an engineered electromagnetic response. A metasurface that yields an electric response is fabricated, experimentally characterized, and a method to obtain a <span class="hlt">magnetic</span> response at optical frequencies is theoretically demonstrated. In conclusion, this design methodology paves the way for metasurfaces that are simultaneously subwavelength and low loss.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1227396-electric-magnetic-response-dielectric-dark-states-low-loss-subwavelength-optical-meta-atoms','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1227396-electric-magnetic-response-dielectric-dark-states-low-loss-subwavelength-optical-meta-atoms"><span id="translatedtitle">Electric and <span class="hlt">magnetic</span> response in dielectric dark states for low loss subwavelength optical meta <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Jain, Aditya; Moitra, Parikshit; Koschny, Thomas; Valentine, Jason; Soukoulis, Costas M.</p> <p>2015-07-14</p> <p>Artificially created surfaces or metasurfaces, composed of appropriately shaped subwavelength structures, namely, meta-<span class="hlt">atoms</span>, control light at subwavelength scales. Historically, metasurfaces have used radiating metallic resonators as subwavelength inclusions. However, while resonant optical metasurfaces made from metal have been sufficiently subwavelength in the propagation direction, they are too lossy for many applications. Metasurfaces made out of radiating dielectric resonators have been proposed to solve the loss problem, but are marginally subwavelength at optical frequencies. We designed subwavelength resonators made out of nonradiating dielectrics. The resonators are decorated with appropriately placed scatterers, resulting in a meta-<span class="hlt">atom</span> with an engineered electromagnetic response. Amore » metasurface that yields an electric response is fabricated, experimentally characterized, and a method to obtain a <span class="hlt">magnetic</span> response at optical frequencies is theoretically demonstrated. In conclusion, this design methodology paves the way for metasurfaces that are simultaneously subwavelength and low loss.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22093575','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22093575"><span id="translatedtitle">Experimental study of linear <span class="hlt">magnetic</span> dichroism in photoionization satellite transitions of <span class="hlt">atomic</span> rubidium</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jaenkaelae, K.; Alagia, M.; Feyer, V.; Richter, R.; Prince, K. C.</p> <p>2011-11-15</p> <p>Laser orientation in the initial state has been used to study the properties of satellite transitions in inner-shell photoionization of rubidium <span class="hlt">atoms</span>. The linear <span class="hlt">magnetic</span> dichroism in the angular distribution (LMDAD) has been utilized to probe the continuum waves of orbital angular momentum conserving monopole, and angular momentum changing conjugate satellites, accompanying the 4p ionization of <span class="hlt">atomic</span> Rb. We show experimentally that LMDAD of both types of satellite transitions is nonzero and that LMDAD of monopole satellites, measured as a function of photon energy, mimics the LMDAD of direct photoionization, whereas the LMDAD of conjugate transitions deviates drastically from that trend. The results indicate that conjugate transitions cannot be described theoretically without explicit inclusion of electron-electron interaction. The present data can thus be used as a very precise test of current models for photoionization.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhST..164a4012Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhST..164a4012Y"><span id="translatedtitle">Visualizing Majorana fermions in a chain of <span class="hlt">magnetic</span> <span class="hlt">atoms</span> on a superconductor</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yazdani, Ali</p> <p>2015-12-01</p> <p>A chain of <span class="hlt">magnetic</span> <span class="hlt">atoms</span> on the surface of a superconductor provides a versatile platform for realizing a one-dimensional topological superconductivity phase with edge-bounded Majorana fermions zero modes. This platform lends itself to spatial resolved measurements with scanning tunneling microscope (STM) that enables direct visualization of the presence of a localized Majorana zero mode. Experiments on self-assembled chains of Fe <span class="hlt">atoms</span> on the surface of Pb show that such a system can be experimentally fabricated and studied using various high-resolution STM measurement techniques. Spatial and energy resolved STM experiments provide strong evidence for Majorana bound states that emerge due to the combination of Fe’s ferromagnetism and spin-orbit coupling of the superconducting Pb substrate. These studies provide a roadmap for optimizing topological superconductivity in this one-dimensional platform and its extension to realize chiral two-dimensional superconductors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20366759','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20366759"><span id="translatedtitle"><span class="hlt">Magnetically</span> controlled exchange process in an ultracold <span class="hlt">atom</span>-dimer mixture.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Knoop, S; Ferlaino, F; Berninger, M; Mark, M; Ngerl, H-C; Grimm, R; D'Incao, J P; Esry, B D</p> <p>2010-02-01</p> <p>We report on the observation of an elementary exchange process in an optically trapped ultracold sample of <span class="hlt">atoms</span> and Feshbach molecules. We can <span class="hlt">magnetically</span> control the energetic nature of the process and tune it from endoergic to exoergic, enabling the observation of a pronounced threshold behavior. In contrast to relaxation to more deeply bound molecular states, the exchange process does not lead to trap loss. We find excellent agreement between our experimental observations and calculations based on the solutions of three-body Schrdinger equation in the adiabatic hyperspherical representation. The high efficiency of the exchange process is explained by the halo character of both the initial and final molecular states. PMID:20366759</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22029893','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22029893"><span id="translatedtitle">Ionization of helium <span class="hlt">atoms</span> under the effect of the antineutrino <span class="hlt">magnetic</span> moment</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Martemyanov, V. P. Tsinoev, V. G.</p> <p>2011-12-15</p> <p>Differential cross sections for inelastic antineutrino interaction with a helium <span class="hlt">atom</span> are calculated. It is shown that, in the energy-transfer range extending up to 1 keV, the cross sections in question are considerably enhanced in the electromagnetic-interaction channel in relation to the cross sections for elastic scattering on a free electron. Absolute cross-section values are of interest in searches for the antineutrino <span class="hlt">magnetic</span> moment, provided that its value in Bohr magneton units falls within the range (10{sup -13}-10{sup -12}){sub Micro-Sign B}.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001PhRvB..64v4409P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001PhRvB..64v4409P"><span id="translatedtitle">Mapping the <span class="hlt">magnetic</span> phase diagram of metastable fct Fe/Cu(100) using Co <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pierce, J. P.; Torija, M. A.; Shen, J.; Plummer, E. W.</p> <p>2001-12-01</p> <p>In ultrathin Fe films grown at room temperature on Cu(100), observed thickness and temperature-dependent spin reorientations are preceded by structural transformations. We use a method involving Co capping <span class="hlt">atoms</span> to generate a <span class="hlt">magnetic</span> phase diagram for this system in the absence of these structural changes. The phase diagram shows that the recently observed stripe-phase melting in the Fe/Cu(100) system is related to the onset of a spin reorientation, rather than to a ferromagnetic-to-paramagnetic transition. In addition, the phase diagram allows us to determine the temperature-dependent anisotropy constants for Fe/Cu(100) films.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ApPhL.102n3702M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ApPhL.102n3702M"><span id="translatedtitle"><span class="hlt">Atomic</span> force microscopy-coupled microcoils for cellular-scale nuclear <span class="hlt">magnetic</span> resonance spectroscopy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mousoulis, Charilaos; Maleki, Teimour; Ziaie, Babak; Neu, Corey P.</p> <p>2013-04-01</p> <p>We present the coupling of <span class="hlt">atomic</span> force microscopy (AFM) and nuclear <span class="hlt">magnetic</span> resonance (NMR) technologies to enable topographical, mechanical, and chemical profiling of biological samples. Here, we fabricate and perform proof-of-concept testing of radiofrequency planar microcoils on commercial AFM cantilevers. The sensitive region of the coil was estimated to cover an approximate volume of 19.4 103 ?m3 (19.4 pl). Functionality of the spectroscopic module of the prototype device is illustrated through the detection of 1? resonance in deionized water. The acquired spectra depict combined NMR capability with AFM that may ultimately enable biophysical and biochemical studies at the single cell level.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/538497','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/538497"><span id="translatedtitle">Discrete variable representation for highly excited states of hydrogen <span class="hlt">atoms</span> in <span class="hlt">magnetic</span> fields</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Grozdanov, T.P.; Andric, L.; Manescu, C.; McCarroll, R.; Grozdanov, T.P.</p> <p>1997-09-01</p> <p>A discrete variable representation (DVR) appropriate for describing the highly excited states of hydrogen <span class="hlt">atoms</span> in laboratory-strength <span class="hlt">magnetic</span> fields is constructed by using a symmetry-adapted direct product of one-dimensional DVR{close_quote}s in parabolic coordinates related to generalized Gauss-Laguerre quadratures. The resulting sparse Hamiltonian matrix is used in an iterative (filter-diagonalization) procedure to obtain eigenvalues and eigenvectors in a given spectral domain. The method is applied to calculate eigenvalues and lifetimes of {open_quotes}circular{close_quotes} Rydberg states, as well as oscillator strengths for the excitation of highly excited states. {copyright} {ital 1997} {ital The American Physical Society}</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3637277','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3637277"><span id="translatedtitle"><span class="hlt">Atomic</span> force microscopy-coupled microcoils for cellular-scale nuclear <span class="hlt">magnetic</span> resonance spectroscopy</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Mousoulis, Charilaos; Maleki, Teimour; Ziaie, Babak; Neu, Corey P.</p> <p>2013-01-01</p> <p>We present the coupling of <span class="hlt">atomic</span> force microscopy (AFM) and nuclear <span class="hlt">magnetic</span> resonance (NMR) technologies to enable topographical, mechanical, and chemical profiling of biological samples. Here, we fabricate and perform proof-of-concept testing of radiofrequency planar microcoils on commercial AFM cantilevers. The sensitive region of the coil was estimated to cover an approximate volume of 19.4??103??m3 (19.4?pl). Functionality of the spectroscopic module of the prototype device is illustrated through the detection of 1? resonance in deionized water. The acquired spectra depict combined NMR capability with AFM that may ultimately enable biophysical and biochemical studies at the single cell level. PMID:24719493</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015MPLB...2950248Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MPLB...2950248Y"><span id="translatedtitle">Quantum chaos and statistical properties of energy levels for <span class="hlt">atom</span> in parallel electric and <span class="hlt">magnetic</span> fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Hai-Feng; Tan, Yong-Gang; Liu, Zhong-Li; Fu, Hong-Zhi</p> <p>2015-12-01</p> <p>In this paper, the statistical properties of energy levels are studied numerically for <span class="hlt">atom</span> in parallel electric and <span class="hlt">magnetic</span> fields, which is an ideal system to examine the contributions of external fields and ionic core to quantum chaos. The Stark maps of diamagnetic spectra and nearest neighbor spacing (NNS) distributions are obtained by diagonalization method incorporating core effect. We identify obvious level anti-crossing and large value of q for barium, indicating that core effect has predominant contribution to chaotic dynamics in barium. To study the core effect in detail, we sweep the quantum defect artificially and find that larger core effect will undoubtedly induce stronger chaotic dynamics.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6851821','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6851821"><span id="translatedtitle">Circular Rydberg States of the Hydrogen <span class="hlt">Atom</span> in a <span class="hlt">Magnetic</span> Field</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Germann, T.C.; Herschbach, D.R. ); Dunn, M.; Watson, D.K. )</p> <p>1995-01-30</p> <p>Dimensional perturbation theory is used to study circular Rydberg states ([vert bar][ital m][vert bar]=[ital n][minus]1[much gt]1) and other large [vert bar][ital m][vert bar] states of the hydrogen <span class="hlt">atom</span> in a uniform <span class="hlt">magnetic</span> field. Because of a degeneracy between states of increased angular momentum and states of increased Cartesian dimensionality, the accuracy of the zeroth-order [ital D][r arrow][infinity] limit and a dimensional perturbation expansion improves significantly for states with larger [vert bar][ital m][vert bar]. In contrast to other approaches, this method is applicable to the entire range of <span class="hlt">magnetic</span> field strengths. Energies and expectation values are presented as functions of the field strength.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22304149','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22304149"><span id="translatedtitle"><span class="hlt">Magnetic</span> property of transition metal-Si <span class="hlt">atomic</span> line on silicon ?3 grain boundary: A theoretical study</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Li, Yong-Hua Guo, Shu-Kuan; Ma, Zhong-Quan; Qu, Guo-Hui; Shi, Ting-Ting; Xia, Qin; Gong, Xin-Gao; Wei, Su-Huai</p> <p>2014-06-14</p> <p>Using first-principles calculations within density functional theory, we investigate the electronic and <span class="hlt">magnetic</span> properties of different 3d transition metal-Si <span class="hlt">atomic</span> lines on silicon ?3 (112) grain boundary, which can be formed through grain boundary segregation. We find that (i) Fe <span class="hlt">atoms</span> occupy the substitutional sites at the grain boundary and form an Fe-Si <span class="hlt">atomic</span> line, but the interaction between the Fe <span class="hlt">atoms</span> is antiferromagnetic. (ii) The ferromagnetic stability increases with the <span class="hlt">atomic</span> number of the transition metals and Co-Si <span class="hlt">atomic</span> line is more stable in the ferromagnetic phase and shows a semimetallic behavior. We suggest that this special TM-Si <span class="hlt">atomic</span> line formed by thermodynamically favorable transition metal segregation on Si grain boundary could be used in design of spin-dependent quantum devices.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003ApPhL..82.2236S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003ApPhL..82.2236S"><span id="translatedtitle">Determination of radiation exposure history of common materials and computer hardware by using <span class="hlt">atomic</span> (and <span class="hlt">magnetic</span> force) microscopy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sharma, J.; Teter, J. P.; Abbundi, R. J.; Guardala, N. A.</p> <p>2003-04-01</p> <p>Defects produced by ionizing radiation are smaller than a micrometer and are unobservable in an optical microscope. An <span class="hlt">atomic</span> force microscope was utilized to reveal their counts and structure in common materials like mica, silicon, organic solids, polymers, sugar, quartz, and calcite. A <span class="hlt">magnetic</span> force microscope has shown the damage of radiation on computer hard disks. The present work shows that exposure to radioactive material leaves a permanent record, which can be read for dosimetric or forensic purposes by using <span class="hlt">atomic</span> force microcopy on common objects or a <span class="hlt">magnetic</span> force microscope on <span class="hlt">magnetic</span> media.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23271648','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23271648"><span id="translatedtitle"><span class="hlt">Atomic</span>-scale engineering of <span class="hlt">magnetic</span> anisotropy of nanostructures through interfaces and interlines.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ouazi, S; Vlaic, S; Rusponi, S; Moulas, G; Buluschek, P; Halleux, K; Bornemann, S; Mankovsky, S; Minr, J; Staunton, J B; Ebert, H; Brune, H</p> <p>2012-01-01</p> <p>The central goals of nanoscale <span class="hlt">magnetic</span> materials science are the self-assembly of the smallest structure exhibiting ferromagnetic hysteresis at room temperature, and the assembly of these structures into the highest density patterns. The focus has been on chemically ordered alloys combining <span class="hlt">magnetic</span> 3d elements with polarizable 5d elements having high spin-orbit coupling and thus yielding the desired large magneto-crystalline anisotropy. The chemical synthesis of nanoparticles of these alloys yields disordered phases requiring annealing to transform them to the high-anisotropy L1(0) structure. Despite considerable efforts, so far only part of the nanoparticles can be transformed without coalescence. Here we present an alternative approach to homogeneous alloys, namely the creation of nanostructures with <span class="hlt">atomically</span> sharp bimetallic interfaces and interlines. They exhibit unexpectedly high <span class="hlt">magnetization</span> reversal energy with values and directions of the easy <span class="hlt">magnetization</span> axes strongly depending on chemistry and texture. We find significant deviations from the expected behaviour for commonly used element combinations. Ab-initio calculations reproduce these results and unravel their origin. PMID:23271648</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3535417','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3535417"><span id="translatedtitle"><span class="hlt">Atomic</span>-scale engineering of <span class="hlt">magnetic</span> anisotropy of nanostructures through interfaces and interlines</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ouazi, S.; Vlaic, S.; Rusponi, S.; Moulas, G.; Buluschek, P.; Halleux, K.; Bornemann, S.; Mankovsky, S.; Minr, J.; Staunton, J.B.; Ebert, H.; Brune, H.</p> <p>2012-01-01</p> <p>The central goals of nanoscale <span class="hlt">magnetic</span> materials science are the self-assembly of the smallest structure exhibiting ferromagnetic hysteresis at room temperature, and the assembly of these structures into the highest density patterns. The focus has been on chemically ordered alloys combining <span class="hlt">magnetic</span> 3d elements with polarizable 5d elements having high spinorbit coupling and thus yielding the desired large magneto-crystalline anisotropy. The chemical synthesis of nanoparticles of these alloys yields disordered phases requiring annealing to transform them to the high-anisotropy L10 structure. Despite considerable efforts, so far only part of the nanoparticles can be transformed without coalescence. Here we present an alternative approach to homogeneous alloys, namely the creation of nanostructures with <span class="hlt">atomically</span> sharp bimetallic interfaces and interlines. They exhibit unexpectedly high <span class="hlt">magnetization</span> reversal energy with values and directions of the easy <span class="hlt">magnetization</span> axes strongly depending on chemistry and texture. We find significant deviations from the expected behaviour for commonly used element combinations. Ab-initio calculations reproduce these results and unravel their origin. PMID:23271648</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120..964O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120..964O"><span id="translatedtitle">Interplanetary <span class="hlt">magnetic</span> field dependence of the suprathermal energetic neutral <span class="hlt">atoms</span> originated in subsolar magnetopause</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ogasawara, K.; Dayeh, M. A.; Funsten, H. O.; Fuselier, S. A.; Livadiotis, G.; McComas, D. J.</p> <p>2015-02-01</p> <p>Using energetic neutral <span class="hlt">atom</span> (ENA) emission observations of the subsolar magnetopause measured by the Interstellar Boundary Explorer (IBEX), we study the correlation between the upstream interplanetary <span class="hlt">magnetic</span> field (IMF) conditions and the spectral index of the source ion population. Our ENA data set includes hour-averaged ENA measurements at energies between 0.5 and 6 keV obtained by the IBEX High Energy ENA imager from January 2009 to May 2011. Under the condition of quiet geomagnetic activity (SYM-H index >-20 nT), we find that the shallower spectra in the suprathermal tail of the ion population of the subsolar magnetopause is weakly correlated (correlation coefficient of -0.30) with the shock angle of the Earth's bow shock, but not correlated with parameters related to <span class="hlt">magnetic</span> reconnection (i.e., elevation and clock angle of the interplanetary <span class="hlt">magnetic</span> field orientation). The observed correlation suggests suprathermal ion energization from diffusive shock acceleration and thus that the suprathermal ions in the subsolar magnetopause are of shocked solar wind origin. We also argue that the roles of magnetospheric ion leakage or ion acceleration by <span class="hlt">magnetic</span> reconnection are reduced in the magnetopause emissions compared to shock acceleration processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22409951','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22409951"><span id="translatedtitle">Large perpendicular <span class="hlt">magnetic</span> anisotropy of single Co <span class="hlt">atom</span> on MgO monolayer: A first-principles study</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Shao, Bin; Shi, Wu-Jun; Feng, Min; Zuo, Xu</p> <p>2015-05-07</p> <p>Realizing the <span class="hlt">magnetic</span> bit with a single <span class="hlt">atom</span> is the ultimate goal for <span class="hlt">magnetic</span> storage. Based on density functional theory, the <span class="hlt">magnetic</span> anisotropy (MA) of single Co <span class="hlt">atom</span> on MgO monolayer has been investigated. Results show that this two dimensional system possesses a large perpendicular MA, about 5.8?meV per Co <span class="hlt">atom</span>. Besides, there exists remarkable unquenched orbital moments for different <span class="hlt">magnetization</span> directions, which can be attributed to the reduction of coordination number in two dimensional system and is responsible for the enhanced MA. The Bloch pseudo-wavefunction and band structure of Co d-orbitals have been calculated to elucidate the origin of the perpendicular MA.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApPhL.107z3104Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApPhL.107z3104Z"><span id="translatedtitle">Highly tunable <span class="hlt">magnetism</span> in silicene doped with Cr and Fe <span class="hlt">atoms</span> under isotropic and uniaxial tensile strain</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zheng, Rui; Chen, Ying; Ni, Jun</p> <p>2015-12-01</p> <p>We have investigated the <span class="hlt">magnetic</span> properties of silicene doped with Cr and Fe <span class="hlt">atoms</span> under isotropic and uniaxial tensile strain by the first-principles calculations. We find that Cr and Fe doped silicenes show strain-tunable <span class="hlt">magnetism</span>. (1) The <span class="hlt">magnetism</span> of Cr and Fe doped silicenes exhibits sharp transitions from low spin states to high spin states by a small isotropic tensile strain. Specially for Fe doped silicene, a nearly nonmagnetic state changes to a high <span class="hlt">magnetic</span> state by a small isotropic tensile strain. (2) The <span class="hlt">magnetic</span> moments of Fe doped silicene also show a sharp jump to 2 ?B at a small threshold of the uniaxial strain, and the <span class="hlt">magnetic</span> moments of Cr doped silicene increase gradually to 4 ?B with the increase of uniaxial strain. (3) The electronic and <span class="hlt">magnetic</span> properties of Cr and Fe doped silicenes are sensitive to the magnitude and direction of the external strain. The highly tunable <span class="hlt">magnetism</span> may be applied in the spintronic devices.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5102002','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5102002"><span id="translatedtitle">Urban <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kukla, G.; Gavin, J.; Karl, T.R.</p> <p>1986-09-01</p> <p>Meteorological stations located in an urban environment in North America <span class="hlt">warmed</span> between 1941 and 1980, compared to the countryside, at an average rate of about 0,12 /sup 0/C per decade. Secular trends of surface air temperature computed predominately from such station data are likely to have a serious <span class="hlt">warm</span> bias.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4464147','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4464147"><span id="translatedtitle">Tailoring the <span class="hlt">magnetic</span> anisotropy of Py/Ni bilayer films using well aligned <span class="hlt">atomic</span> steps on Cu(001)</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ma, S.; Tan, A.; Deng, J. X.; Li, J.; Zhang, Z. D.; Hwang, C.; Qiu, Z. Q.</p> <p>2015-01-01</p> <p>Tailoring the spin orientation at the <span class="hlt">atomic</span> scale has been a key task in spintronics technology. While controlling the out-of-plane to in-plane spin orientation has been achieved by a precise control of the perpendicular <span class="hlt">magnetic</span> anisotropy at <span class="hlt">atomic</span> layer thickness level, a design and control of the in-plane <span class="hlt">magnetic</span> anisotropy has not yet been well developed. On well aligned <span class="hlt">atomic</span> steps of a 6 vicinal Cu(001) surface with steps parallel to the [110] axis, we grow Py/Ni overlayer films epitaxially to permit a systematic exploration of the step-induced in-plane <span class="hlt">magnetic</span> anisotropy as a function of both the Py and the Ni film thicknesses. We found that the <span class="hlt">atomic</span> steps from the vicinal Cu(001) induce an in-plane uniaxial <span class="hlt">magnetic</span> anisotropy that favors both Py and Ni <span class="hlt">magnetizations</span> perpendicular to the steps, opposite to the behavior of Co on vicinal Cu(001). In addition, thickness-dependent study shows that the Ni films exhibit different <span class="hlt">magnetic</span> anisotropy below and above ~6?ML Ni thickness. PMID:26067408</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhRvB..85v4406U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhRvB..85v4406U"><span id="translatedtitle">Interface <span class="hlt">atomic</span> structures and <span class="hlt">magnetic</span> anisotropy of Fe and Pd/Fe monatomic films on Pd(001)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ueno, Tetsuro; Sawada, Masahiro; Furumoto, Kazuhito; Tagashira, Tetsuro; Tohoda, Satoshi; Kimura, Akio; Haraguchi, Shinya; Tsujikawa, Masahito; Oda, Tatsuki; Namatame, Hirofumi; Taniguchi, Masaki</p> <p>2012-06-01</p> <p>The <span class="hlt">magnetic</span> anisotropy of monatomic Fe films on Pd(001) with or without a Pd overlayer was investigated from the standpoint of interface <span class="hlt">atomic</span> structures. Quantitative analysis included low-energy electron diffraction and x-ray <span class="hlt">magnetic</span> circular dichroism (XMCD) experiments, and first-principles calculations were also performed on monatomic Fe and Pd/Fe systems. It was revealed that Fe <span class="hlt">atoms</span> intermix with the Pd substrate at room temperature. A spin reorientation transition occurs at a critical Fe thickness of 1.2 monolayers (ML) in Fe/Pd(001), while in-plane <span class="hlt">magnetic</span> anisotropy is persistent in Pd/Fe/Pd(001) throughout the entire sample. The Fe 3d spin and orbital <span class="hlt">magnetic</span> moments for both systems are strongly enhanced near 1 ML Fe thickness, as compared to those of the bulk iron crystal. In addition, an induced <span class="hlt">magnetic</span> moment in interfacial Pd <span class="hlt">atoms</span> was observed by XMCD at the Pd M2,3 core absorption edges. It was concluded that the L10-like tetragonally distorted interface <span class="hlt">atomic</span> structure in monatomic Fe/Pd(001) induces the perpendicular <span class="hlt">magnetic</span> anisotropy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NatSR...511055M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NatSR...511055M"><span id="translatedtitle">Tailoring the <span class="hlt">magnetic</span> anisotropy of Py/Ni bilayer films using well aligned <span class="hlt">atomic</span> steps on Cu(001)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ma, S.; Tan, A.; Deng, J. X.; Li, J.; Zhang, Z. D.; Hwang, C.; Qiu, Z. Q.</p> <p>2015-06-01</p> <p>Tailoring the spin orientation at the <span class="hlt">atomic</span> scale has been a key task in spintronics technology. While controlling the out-of-plane to in-plane spin orientation has been achieved by a precise control of the perpendicular <span class="hlt">magnetic</span> anisotropy at <span class="hlt">atomic</span> layer thickness level, a design and control of the in-plane <span class="hlt">magnetic</span> anisotropy has not yet been well developed. On well aligned <span class="hlt">atomic</span> steps of a 6 vicinal Cu(001) surface with steps parallel to the [110] axis, we grow Py/Ni overlayer films epitaxially to permit a systematic exploration of the step-induced in-plane <span class="hlt">magnetic</span> anisotropy as a function of both the Py and the Ni film thicknesses. We found that the <span class="hlt">atomic</span> steps from the vicinal Cu(001) induce an in-plane uniaxial <span class="hlt">magnetic</span> anisotropy that favors both Py and Ni <span class="hlt">magnetizations</span> perpendicular to the steps, opposite to the behavior of Co on vicinal Cu(001). In addition, thickness-dependent study shows that the Ni films exhibit different <span class="hlt">magnetic</span> anisotropy below and above ~6?ML Ni thickness.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvB..92o5433L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvB..92o5433L"><span id="translatedtitle">Coherent manipulation of a single <span class="hlt">magnetic</span> <span class="hlt">atom</span> using polarized single electron transport in a double quantum dot</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lai, Wenxi; Yang, Wen</p> <p>2015-10-01</p> <p>We consider theoretically a <span class="hlt">magnetic</span> impurity spin driven by polarized electrons tunneling through a double-quantum-dot system. The spin-blockade effect and spin conservation in the system make the <span class="hlt">magnetic</span> impurity sufficiently interact with each transferring electron. As a result, a single collected electron carries information about spin change of the <span class="hlt">magnetic</span> impurity. The scheme may develop all-electrical manipulation of <span class="hlt">magnetic</span> <span class="hlt">atoms</span> by means of single electrons, which is significant for the implementation of scalable logical gates in information processing systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22080205','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22080205"><span id="translatedtitle">4-Component relativistic <span class="hlt">magnetically</span> induced current density using London <span class="hlt">atomic</span> orbitals.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sulzer, David; Olejniczak, Ma?gorzata; Bast, Radovan; Saue, Trond</p> <p>2011-12-14</p> <p>We present the implementation and application of 4-component relativistic <span class="hlt">magnetically</span> induced current density using London <span class="hlt">atomic</span> orbitals for self-consistent field models. We obtain a <span class="hlt">magnetically</span> balanced basis by a simple scheme where orbitals obtained by imposing restricted kinetic balance are extended by their unrestricted kinetic balance complement. The presented methodology makes it possible to analyze the concept of aromaticity based on the ring current criterion for closed-shell molecules across the periodic table and is independent of the choice of gauge origin. As a first illustration of the methodology we study plots of the <span class="hlt">magnetically</span> induced current density and its divergence in the series C(5)H(5)E (E = CH, N, P, As, Sb, Bi) at the Kohn-Sham level, as well as integrated ring current susceptibilities, which we compare to previous results (R. Bast et al., Chem. Phys., 2009, 356, 187) obtained using a common gauge origin approach. We find that the current strength decreases monotonically along the series, but that all molecules qualify as aromatic according to the ring current criterion. PMID:22080205</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21528893','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21528893"><span id="translatedtitle">Scattering amplitude of ultracold <span class="hlt">atoms</span> near the p-wave <span class="hlt">magnetic</span> Feshbach resonance</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zhang Peng; Naidon, Pascal; Ueda, Masahito</p> <p>2010-12-15</p> <p>Most of the current theories on the p-wave superfluid in cold <span class="hlt">atomic</span> gases are based on the effective-range theory for the two-body scattering, where the low-energy p-wave scattering amplitude f{sub 1}(k) is given by f{sub 1}(k)=-1/[ik+1/(Vk{sup 2})+1/R]. Here k is the incident momentum, V and R are the k-independent scattering volume and effective range, respectively. However, due to the long-range nature of the van der Waals interaction between two colliding ultracold <span class="hlt">atoms</span>, the p-wave scattering amplitude of the two <span class="hlt">atoms</span> is not described by the effective-range theory [J. Math. Phys. 4, 54 (1963); Phys. Rev. A 58, 4222 (1998)]. In this paper we provide an explicit calculation for the p-wave scattering of two ultracold <span class="hlt">atoms</span> near the p-wave <span class="hlt">magnetic</span> Feshbach resonance. We show that in this case the low-energy p-wave scattering amplitude f{sub 1}(k)=-1/[ik+1/(V{sup eff}k{sup 2})+1/(S{sup eff}k)+1/R{sup eff}] where V{sup eff}, S{sup eff}, and R{sup eff} are k-dependent parameters. Based on this result, we identify sufficient conditions for the effective-range theory to be a good approximation of the exact scattering amplitude. Using these conditions we show that the effective-range theory is a good approximation for the p-wave scattering in the ultracold gases of {sup 6}Li and {sup 40}K when the scattering volume is enhanced by the resonance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25350487','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25350487"><span id="translatedtitle">Heavy <span class="hlt">atom</span> effect on <span class="hlt">magnetic</span> anisotropy of matrix-isolated monobromine substituted septet trinitrene.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Misochko, Eugenii Ya; Masitov, Artem A; Akimov, Alexander V; Korchagin, Denis V; Chapyshev, Sergei V</p> <p>2015-03-19</p> <p>The heavy <span class="hlt">atom</span> effect on the <span class="hlt">magnetic</span> anisotropy of septet trinitrenes is reported. Septet 1-bromo-3,5-dichloro-2,4,6-trinitrenobenzene (S-1) was generated in a solid argon matrix by ultraviolet irradiation of 1,3,5-triazido-2-bromo-4,6-dichlorobenzene. This trinitrene displays an electron spin resonance (ESR) spectrum that drastically differs from ESR spectra of all previously studied septet trinitrenes. The zero-field splitting (ZFS) parameters, derived from the experimental spectrum, show the parameter |D| = 0.1237 cm(-1) and the unprecedentedly large ratio of E/D = 0.262 that is close to the rhombic limit E/D = 1/3 for high-spin molecules. The CASCI (based on state-averaged CASSCF) and DFT methods were applied to calculate the ZFS tensor focusing on the heavy (bromine) <span class="hlt">atom</span> effects on the spin-orbit term. These calculations show that the multiconfigurational ab initio formalism and the CASCI method are the most successful for accurate predictions of the spin-orbit term in the ZFS tensor of high-spin nitrenes containing heavy bromine <span class="hlt">atoms</span>. Due to the presence of the bromine <span class="hlt">atom</span> in S-1, the contribution of the spin-orbit term to the total parameter D is dominant and responsible for the unusual orientation of the easy Z-axis lying in the molecular plane perpendicular to the C-Br bond. As a result, the principal values D(XX), D(YY), and D(ZZ) of the total tensor D?(Tot) have such magnitudes and signs for which the ratio E/D is close to the rhombic limit, and the total parameter D is large in magnitude and positive in sign. PMID:25350487</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16606175','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16606175"><span id="translatedtitle"><span class="hlt">Magnetic</span> field-induced spectroscopy of forbidden optical transitions with application to lattice-based optical <span class="hlt">atomic</span> clocks.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Taichenachev, A V; Yudin, V I; Oates, C W; Hoyt, C W; Barber, Z W; Hollberg, L</p> <p>2006-03-01</p> <p>We develop a method of spectroscopy that uses a weak static <span class="hlt">magnetic</span> field to enable direct optical excitation of forbidden electric-dipole transitions that are otherwise prohibitively weak. The power of this scheme is demonstrated using the important application of optical <span class="hlt">atomic</span> clocks based on neutral <span class="hlt">atoms</span> confined to an optical lattice. The simple experimental implementation of this method--a single clock laser combined with a dc <span class="hlt">magnetic</span> field--relaxes stringent requirements in current lattice-based clocks (e.g., <span class="hlt">magnetic</span> field shielding and light polarization), and could therefore expedite the realization of the extraordinary performance level predicted for these clocks. We estimate that a clock using alkaline-earth-like <span class="hlt">atoms</span> such as Yb could achieve a fractional frequency uncertainty of well below 10(-17) for the metrologically preferred even isotopes. PMID:16606175</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/10175853','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/10175853"><span id="translatedtitle">RHIC <span class="hlt">warm</span>-bore systems</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Welch, K.M.</p> <p>1994-07-01</p> <p>Pressure profiles, in time, are calculated as a consequence of anticipated outgassing of various beam components (e.g., rf cavities, etc.) and <span class="hlt">warm</span>-bore beam pipes. Gold beam lifetimes and transverse beam emittance growth are given for calculated average pressures. Examples of undesirable <span class="hlt">warm</span>-bore conditions are presented such as contaminated experimental beam pipes and <span class="hlt">warm</span>-bore <span class="hlt">magnets</span> (i.e., DX). These examples may prove instructive. The methods used in making these calculations are presented in Section 2. They are applicable to all linear systems. The calculations given apply to the RHIC accelerator and more specifically to <span class="hlt">warm</span>-bore regions of the machine.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22156293','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22156293"><span id="translatedtitle"><span class="hlt">Atomic</span> disorder and the <span class="hlt">magnetic</span>, electrical, and optical properties of a Co{sub 2}CrAl Heusler alloy</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Svyazhin, A. D. Shreder, E. I.; Voronin, V. I.; Berger, I. F.; Danilov, S. E.</p> <p>2013-03-15</p> <p>Two Co{sub 2}CrAl alloy samples subjected to different heat treatment regimes are studied. An exact distribution of <span class="hlt">atoms</span> over the sublattices in the samples is determined by X-ray diffraction and neutron diffraction methods. These data are used to perform ab initio density of states calculations and to calculate the <span class="hlt">magnetic</span> moments of the samples in a coherent potential approximation. The calculated <span class="hlt">magnetic</span> moments are compared to the experimental values. The effect of <span class="hlt">atomic</span> ordering on the electronic structure near the Fermi level is analyzed using optical methods. The possible causes of the detected temperature dependence of the electrical resistivity, unusual for metallic alloys, are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008JChPh.128h4306W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008JChPh.128h4306W"><span id="translatedtitle">Stability and <span class="hlt">magnetic</span> properties of transition metal <span class="hlt">atoms</span> endohedral BnNn (n=12-28) cages</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Jianguang; Ma, Li; Zhao, Jijun; Wang, Baolin; Wang, Guanghou</p> <p>2008-02-01</p> <p>First-principles calculations have been conducted to systemically investigate the stability and <span class="hlt">magnetic</span> properties of 3d and 4d transitional-metal (TM) <span class="hlt">atoms</span> doped in the BnNn (n=12,16,20,24,28) cages. Among those cages, the B24N24 is the optimal one for encapsulating 3d and 4d TM <span class="hlt">atoms</span> according to the computed heat of formation. Inside B24N24 cage, 3d and 4d TM dopants belonging to the same group in the Periodic Table exhibit similar <span class="hlt">magnetic</span> behaviors. Most of the 3d and 4d TM <span class="hlt">atoms</span> remain <span class="hlt">magnetic</span> after doped in the B24N24 cage except for Ni, Zr, and Pd. The magnitudes of the remaining moments for 3d (except for Sc, Ti, and V) and 4d dopants are reduced from those of free <span class="hlt">atoms</span>. The energy gaps are localized at the doped transition metal <span class="hlt">atoms</span>. Encapsulations of two TM <span class="hlt">atoms</span> inside the B24N24 cage were also considered.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21516804','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21516804"><span id="translatedtitle"><span class="hlt">Atomic</span> and Molecular Collisional Radiative Modeling for Spectroscopy of Low Temperature and <span class="hlt">Magnetic</span> Fusion Plasmas</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Fantz, U.; Wuenderlich, D.</p> <p>2011-05-11</p> <p>The quantitative analysis of spectroscopic data from low temperature plasmas is strongly supported from collisional radiative (CR) modeling. Low pressure plasmas for basic research in the lab and for industrial use have several aspects in common with the cold edge of <span class="hlt">magnetic</span> fusion plasmas. On the basis of applications of CR modeling for <span class="hlt">atomic</span> and molecular hydrogen, molecular nitrogen, and diatomic radicals such as CH and C{sub 2}, the relevance of individual processes for data interpretation is demonstrated for ionizing and recombining plasmas. Examples of such processes are opacity, dissociative excitation, dissociative recombination, mutual neutralization, and energy pooling. It is shown that the benchmark of CR modeling with experimental data can be used to identify problems in the ingoing data set of cross sections and rate coefficients. Using the flexible solver Yacora, the capability of CR modeling of low temperature plasmas is highlighted.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20898658','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20898658"><span id="translatedtitle">Quantum and Classical Description of H <span class="hlt">Atom</span> Under <span class="hlt">Magnetic</span> Field and Quadrupole Trap Potential</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mahecha, J.; Salas, J. P.</p> <p>2006-12-01</p> <p>A discussion regarding the energy levels spectrum of quantum systems whose classical analogous has states of chaotic motion is presented. The chaotic dynamics of the classical underlying system has its manifestation in the wave functions (in the form of 'scars') and in the energy levels (in the form of 'statistical repulsion' of the energy levels). The above mentioned signatures are named 'quantum chaos'. A typical study of quantum chaos requires finding accurate energy eigenvalues of highly excited states, to calculate the nearest neighbors spacing between levels, to perform the 'unfolding' of the spectrum in order to separate the fluctuations, and finally to find the probability distribution of the unfolded spectrum. This is exemplified by the hydrogen <span class="hlt">atom</span> under uniform <span class="hlt">magnetic</span> field and a quadrupole electric field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JaJAP..52e0201I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JaJAP..52e0201I"><span id="translatedtitle"><span class="hlt">Atomic</span>-Resolution X-ray Energy-Dispersive Spectroscopy Chemical Mapping of Substitutional Dy <span class="hlt">Atoms</span> in a High-Coercivity Neodymium <span class="hlt">Magnet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Itakura, Masaru; Watanabe, Natsuki; Nishida, Minoru; Daio, Takeshi; Matsumura, Syo</p> <p>2013-05-01</p> <p>We have investigated local element distributions in a Dy-doped Nd2Fe14B hot-deformed <span class="hlt">magnet</span> by <span class="hlt">atomic</span>-column resolution chemical mapping using an X-ray energy-dispersive spectrometer (XEDS) attached to an aberration-corrected scanning transmission electron microscope (Cs-corrected STEM). The positions of the Nd and Dy <span class="hlt">atomic</span> columns were visualized in the XEDS maps. The substitution of Dy was limited to a surface layer 2-3 unit cells thick in the Nd2Fe14B grains, and the Dy <span class="hlt">atoms</span> preferentially occupied the 4f-Nd sites of Nd2Fe14B. These results provide further insights into the principal mechanism governing the coercivity enhancement due to Dy doping.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18328755','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18328755"><span id="translatedtitle">Structural, electronic, and <span class="hlt">magnetic</span> properties of heterofullerene C(58)Si with odd number of <span class="hlt">atoms</span> and a near planar tetracoordinate Si <span class="hlt">atom</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Feng-Ling; Jalbout, Abraham F</p> <p>2008-06-01</p> <p>Density functional calculations and minimization techniques have been employed to characterize the structural and electronic properties of [5,6]-heterofullerene-C(58)Si-C(2v). Since it has odd number of <span class="hlt">atoms</span> and a near planar tetracoordinate Si <span class="hlt">atom</span> on the skeleton of the cage, it has odd number of <span class="hlt">atoms</span> assembling a cage and is a novel molecule. Vibrational frequencies of the molecule have been calculated at the B3LYP/6-31G* level of theory. The absence of imaginary vibrational frequency confirms that the molecule corresponds to a true minimum on the potential energy hypersurface. Sixteen (13)C nuclear <span class="hlt">magnetic</span> resonance (NMR) spectral signals of C(58)Si are characterized, and its heat of formation was estimated in this work. PMID:18328755</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21560032','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21560032"><span id="translatedtitle">Variational-average-<span class="hlt">atom</span>-in-quantum-plasmas (VAAQP) code and virial theorem: Equation-of-state and shock-Hugoniot calculations for <span class="hlt">warm</span> dense Al, Fe, Cu, and Pb</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Piron, R.; Blenski, T.</p> <p>2011-02-15</p> <p>The numerical code VAAQP (variational average <span class="hlt">atom</span> in quantum plasmas), which is based on a fully variational model of equilibrium dense plasmas, is applied to equation-of-state calculations for aluminum, iron, copper, and lead in the <span class="hlt">warm</span>-dense-matter regime. VAAQP does not impose the neutrality of the Wigner-Seitz ion sphere; it provides the average-<span class="hlt">atom</span> structure and the mean ionization self-consistently from the solution of the variational equations. The formula used for the electronic pressure is simple and does not require any numerical differentiation. In this paper, the virial theorem is derived in both nonrelativistic and relativistic versions of the model. This theorem allows one to express the electron pressure as a combination of the electron kinetic and interaction energies. It is shown that the model fulfills automatically the virial theorem in the case of local-density approximations to the exchange-correlation free-energy. Applications of the model to the equation-of-state and Hugoniot shock adiabat of aluminum, iron, copper, and lead in the <span class="hlt">warm</span>-dense-matter regime are presented. Comparisons with other approaches, including the inferno model, and with available experimental data are given. This work allows one to understand the thermodynamic consistency issues in the existing average-<span class="hlt">atom</span> models. Starting from the case of aluminum, a comparative study of the thermodynamic consistency of the models is proposed. A preliminary study of the validity domain of the inferno model is also included.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21405914','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21405914"><span id="translatedtitle">Variational-average-<span class="hlt">atom</span>-in-quantum-plasmas (VAAQP) code and virial theorem: equation-of-state and shock-Hugoniot calculations for <span class="hlt">warm</span> dense Al, Fe, Cu, and Pb.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Piron, R; Blenski, T</p> <p>2011-02-01</p> <p>The numerical code VAAQP (variational average <span class="hlt">atom</span> in quantum plasmas), which is based on a fully variational model of equilibrium dense plasmas, is applied to equation-of-state calculations for aluminum, iron, copper, and lead in the <span class="hlt">warm</span>-dense-matter regime. VAAQP does not impose the neutrality of the Wigner-Seitz ion sphere; it provides the average-<span class="hlt">atom</span> structure and the mean ionization self-consistently from the solution of the variational equations. The formula used for the electronic pressure is simple and does not require any numerical differentiation. In this paper, the virial theorem is derived in both nonrelativistic and relativistic versions of the model. This theorem allows one to express the electron pressure as a combination of the electron kinetic and interaction energies. It is shown that the model fulfills automatically the virial theorem in the case of local-density approximations to the exchange-correlation free-energy. Applications of the model to the equation-of-state and Hugoniot shock adiabat of aluminum, iron, copper, and lead in the <span class="hlt">warm</span>-dense-matter regime are presented. Comparisons with other approaches, including the inferno model, and with available experimental data are given. This work allows one to understand the thermodynamic consistency issues in the existing average-<span class="hlt">atom</span> models. Starting from the case of aluminum, a comparative study of the thermodynamic consistency of the models is proposed. A preliminary study of the validity domain of the inferno model is also included. PMID:21405914</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22081081','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22081081"><span id="translatedtitle">Induction of coherent <span class="hlt">magnetization</span> switching in a few <span class="hlt">atomic</span> layers of FeCo using voltage pulses.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shiota, Yoichi; Nozaki, Takayuki; Bonell, Frdric; Murakami, Shinichi; Shinjo, Teruya; Suzuki, Yoshishige</p> <p>2012-01-01</p> <p>The <span class="hlt">magnetization</span> direction of a metallic <span class="hlt">magnet</span> has generally been controlled by a <span class="hlt">magnetic</span> field or by spin-current injection into nanosized <span class="hlt">magnetic</span> cells. Both these methods use an electric current to control the <span class="hlt">magnetization</span> direction; therefore, they are energy consuming. <span class="hlt">Magnetization</span> control using an electric field is considered desirable because of its expected ultra-low power consumption and coherent behaviour. Previous experimental approaches towards achieving voltage control of <span class="hlt">magnetization</span> switching have used single ferromagnetic layers with and without piezoelectric materials, ferromagnetic semiconductors, multiferroic materials, and their hybrid systems. However, the coherent control of <span class="hlt">magnetization</span> using voltage signals has not thus far been realized. Also, bistable <span class="hlt">magnetization</span> switching (which is essential in information storage) possesses intrinsic difficulties because an electric field does not break time-reversal symmetry. Here, we demonstrate a coherent precessional <span class="hlt">magnetization</span> switching using electric field pulses in nanoscale <span class="hlt">magnetic</span> cells with a few <span class="hlt">atomic</span> FeCo (001) epitaxial layers adjacent to a MgO barrier. Furthermore, we demonstrate the realization of bistable toggle switching using the coherent precessions. The estimated power consumption for single switching in the ideal equivalent switching circuit can be of the order of 10(4)k(B)T, suggesting a reduction factor of 1/500 when compared with that of the spin-current-injection switching process. PMID:22081081</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhSS...57.1142V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhSS...57.1142V"><span id="translatedtitle">Specific features of the formation of <span class="hlt">atomic</span> <span class="hlt">magnetic</span> moments in amorphous films RE-Co ( RE = La, Gd, Tb)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vas'kovskiy, V. O.; Adanakova, O. A.; Balymov, K. G.; Kulesh, N. A.; Svalov, A. V.; Stepanova, E. A.</p> <p>2015-06-01</p> <p>A systematic investigation of the <span class="hlt">magnetic</span> properties of amorphous films in ( RE) x Co100 - x binary systems in the ground state with rare-earth elements ( RE) of different types has been performed. The concentration dependences of the average <span class="hlt">atomic</span> <span class="hlt">magnetic</span> moments of cobalt ( m Co), gadolinium ( m Gd), and terbium ( m Tb) have been determined from the analysis of the spontaneous <span class="hlt">magnetization</span> of the films with a nonmagnetic rare-earth element (La), a rare-earth element with a spherical electron shell (Gd), and a rareearth element with a large orbital <span class="hlt">magnetic</span> moment (Tb). It has been shown that, in the range 0 < x < 50 at %, the <span class="hlt">magnetic</span> moment m Co decreases from 1.7 ?B to zero, the <span class="hlt">magnetic</span> moment m Gd remains unchanged and almost coincides with the <span class="hlt">magnetic</span> moment of the free <span class="hlt">atom</span> (7 ?B), and the value of m Tb decreases monotonically, but the rate of decrease depends on the method of the sample preparation. The revealed regularities are associated with the concentration change in the electronic structure of cobalt and with the specificity of the <span class="hlt">magnetic</span> structure of the films, which has a ferromagnetic, ferrimagnetic, or sperimagnetic character for samples containing La, Gd, or Tb, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22146013','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22146013"><span id="translatedtitle">Atmospheric chemistry of isoflurane, desflurane, and sevoflurane: kinetics and mechanisms of reactions with chlorine <span class="hlt">atoms</span> and OH radicals and global <span class="hlt">warming</span> potentials.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sulbaek Andersen, Mads P; Nielsen, Ole J; Karpichev, Boris; Wallington, Timothy J; Sander, Stanley P</p> <p>2012-06-21</p> <p>The smog chamber/Fourier-transform infrared spectroscopy (FTIR) technique was used to measure the rate coefficients k(Cl + CF(3)CHClOCHF(2), isoflurane) = (4.5 0.8) 10(-15), k(Cl + CF(3)CHFOCHF(2), desflurane) = (1.0 0.3) 10(-15), k(Cl + (CF(3))(2)CHOCH(2)F, sevoflurane) = (1.1 0.1) 10(-13), and k(OH + (CF(3))(2)CHOCH(2)F) = (3.5 0.7) 10(-14) cm(3) molecule(-1) in 700 Torr of N(2)/air diluent at 295 2 K. An upper limit of 6 10(-17) cm(3) molecule(-1) was established for k(Cl + (CF(3))(2)CHOC(O)F). The laser photolysis/laser-induced fluorescence (LP/LIF) technique was employed to determine hydroxyl radical rate coefficients as a function of temperature (241-298 K): k(OH + CF(3)CHFOCHF(2)) = (7.05 1.80) 10(-13) exp[-(1551 72)/T] cm(3) molecule(-1); k(296 1 K) = (3.73 0.08) 10(-15) cm(3) molecule(-1), and k(OH + (CF(3))(2)CHOCH(2)F) = (9.98 3.24) 10(-13) exp[-(969 82)/T] cm(3) molecule(-1); k(298 1 K) = (3.94 0.30) 10(-14) cm(3) molecule(-1). The rate coefficient of k(OH + CF(3)CHClOCHF(2), 296 1 K) = (1.45 0.16) 10(-14) cm(3) molecule(-1) was also determined. Chlorine <span class="hlt">atoms</span> react with CF(3)CHFOCHF(2) via H-abstraction to give CF(3)CFOCHF(2) and CF(3)CHFOCF(2) radicals in yields of approximately 83% and 17%. The major atmospheric fate of the CF(3)C(O)FOCHF(2) alkoxy radical is decomposition via elimination of CF(3) to give FC(O)OCHF(2) and is unaffected by the method used to generate the CF(3)C(O)FOCHF(2) radicals. CF(3)CHFOCF(2) radicals add O(2) and are converted by subsequent reactions into CF(3)CHFOCF(2)O alkoxy radicals, which decompose to give COF(2) and CF(3)CHFO radicals. In 700 Torr of air 82% of CF(3)CHFO radicals undergo C-C scission to yield HC(O)F and CF(3) radicals with the remaining 18% reacting with O(2) to give CF(3)C(O)F. Atmospheric oxidation of (CF(3))(2)CHOCH(2)F gives (CF(3))(2)CHOC(O)F in a molar yield of 93 6% with CF(3)C(O)CF(3) and HCOF as minor products. The IR spectra of (CF(3))(2)CHOC(O)F and FC(O)OCHF(2) are reported for the first time. The atmospheric lifetimes of CF(3)CHClOCHF(2), CF(3)CHFOCHF(2), and (CF(3))(2)CHOCH(2)F (sevoflurane) are estimated at 3.2, 14, and 1.1 years, respectively. The 100 year time horizon global <span class="hlt">warming</span> potentials of isoflurane, desflurane, and sevoflurane are 510, 2540, and 130, respectively. The atmospheric degradation products of these anesthetics are not of environmental concern. PMID:22146013</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhRvL.108d6803T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhRvL.108d6803T"><span id="translatedtitle"><span class="hlt">Magnetic</span>-Field Probing of an SU(4) Kondo Resonance in a Single-<span class="hlt">Atom</span> Transistor</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tettamanzi, G. C.; Verduijn, J.; Lansbergen, G. P.; Blaauboer, M.; Caldern, M. J.; Aguado, R.; Rogge, S.</p> <p>2012-01-01</p> <p>Semiconductor devices have been scaled to the point that transport can be dominated by only a single dopant <span class="hlt">atom</span>. As a result, in a Si fin-type field effect transistor Kondo physics can govern transport when one electron is bound to the single dopant. Orbital (valley) degrees of freedom, apart from the standard spin, strongly modify the Kondo effect in such systems. Owing to the small size and the s-like orbital symmetry of the ground state of the dopant, these orbital degrees of freedom do not couple to external <span class="hlt">magnetic</span> fields which allows us to tune the symmetry of the Kondo effect. Here we study this tunable Kondo effect and demonstrate experimentally a symmetry crossover from an SU(4) ground state to a pure orbital SU(2) ground state as a function of <span class="hlt">magnetic</span> field. Our claim is supported by theoretical calculations that unambiguously show that the SU(2) symmetric case corresponds to a pure valley Kondo effect of fully polarized electrons.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22400874','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22400874"><span id="translatedtitle"><span class="hlt">Magnetic</span>-field probing of an SU(4) Kondo resonance in a single-<span class="hlt">atom</span> transistor.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tettamanzi, G C; Verduijn, J; Lansbergen, G P; Blaauboer, M; Caldern, M J; Aguado, R; Rogge, S</p> <p>2012-01-27</p> <p>Semiconductor devices have been scaled to the point that transport can be dominated by only a single dopant <span class="hlt">atom</span>. As a result, in a Si fin-type field effect transistor Kondo physics can govern transport when one electron is bound to the single dopant. Orbital (valley) degrees of freedom, apart from the standard spin, strongly modify the Kondo effect in such systems. Owing to the small size and the s-like orbital symmetry of the ground state of the dopant, these orbital degrees of freedom do not couple to external <span class="hlt">magnetic</span> fields which allows us to tune the symmetry of the Kondo effect. Here we study this tunable Kondo effect and demonstrate experimentally a symmetry crossover from an SU(4) ground state to a pure orbital SU(2) ground state as a function of <span class="hlt">magnetic</span> field. Our claim is supported by theoretical calculations that unambiguously show that the SU(2) symmetric case corresponds to a pure valley Kondo effect of fully polarized electrons. PMID:22400874</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013sf2a.conf..415S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013sf2a.conf..415S"><span id="translatedtitle">The structure of the thermally bistable, turbulent and <span class="hlt">magnetized</span> <span class="hlt">atomic</span> gas</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saury, E.; Bracco, A.; Boulanger, F.; Miville-Deschnes, M.-A.; Hennebelle, P.</p> <p>2013-11-01</p> <p>The work presented here is focused on the evolution of the <span class="hlt">atomic</span> and diffuse interstellar medium that provides the initial conditions to the formation of molecular clouds. We quantify the roles of thermal instability, turbulence and <span class="hlt">magnetic</span> field in the formation of CNM gas out of the WNM with numerical simulations performed with the code HERACLES. First, we present the results of a study of the WNM-CNM transition in the non-<span class="hlt">magnetized</span> case. With WNM initial conditions and stirring in of turbulent motions at large scales, the hydrodynamical simulations reproduce basic observational statistics of the diffuse ISM as the mass in the cold phase. A process of compression is needed to create CNM through the thermal instability, either with a majority of compressible modes of the injected turbulent velocity field or with an initial density of the WNM higher than the fiducial value for the thermal equilibrium. Lastly, we present a set of MHD simulations based on the parameter study performed in the hydrodynamical case and compare their ability to create CNM and their properties regarding the dust polarization, as the maps of the stokes parameters and the dispersion of the polarization angle. We obtain a good agreement with the recent results of the Planck satellite.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JMMM..379..137D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JMMM..379..137D"><span id="translatedtitle">A quantitative study of particle size effects in the magnetorelaxometry of <span class="hlt">magnetic</span> nanoparticles using <span class="hlt">atomic</span> magnetometry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dolgovskiy, V.; Lebedev, V.; Colombo, S.; Weis, A.; Michen, B.; Ackermann-Hirschi, L.; Petri-Fink, A.</p> <p>2015-04-01</p> <p>The discrimination of immobilised superparamagnetic iron oxide nanoparticles (SPIONs) against SPIONs in fluid environments via their <span class="hlt">magnetic</span> relaxation behaviour is a powerful tool for bio-medical imaging. Here we demonstrate that a gradiometer of laser-pumped <span class="hlt">atomic</span> magnetometers can be used to record accurate time series of the relaxing <span class="hlt">magnetic</span> field produced by pre-polarised SPIONs. We have investigated dry in vitro maghemite nanoparticle samples with different size distributions (average radii ranging from 14 to 21 nm) and analysed their relaxation using the Nel-Brown formalism. Fitting our model function to the magnetorelaxation (MRX) data allows us to extract the anisotropy constant K and the saturation magnetisation MS of each sample. While the latter was found not to depend on the particle size, we observe that K is inversely proportional to the (time- and size-) averaged volume of the magnetised particle fraction. We have identified the range of SPION sizes that are best suited for MRX detection considering our specific experimental conditions and sample preparation technique.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007PhRvE..75c1707L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007PhRvE..75c1707L"><span id="translatedtitle">Nuclear <span class="hlt">magnetic</span> resonance parameters of <span class="hlt">atomic</span> xenon dissolved in Gay-Berne model liquid crystal</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lintuvuori, Juho; Straka, Michal; Vaara, Juha</p> <p>2007-03-01</p> <p>We present constant-pressure Monte Carlo simulations of nuclear <span class="hlt">magnetic</span> resonance (NMR) spectral parameters, nuclear <span class="hlt">magnetic</span> shielding relative to the free <span class="hlt">atom</span> as well as nuclear quadrupole coupling, for <span class="hlt">atomic</span> xenon dissolved in a model thermotropic liquid crystal. The solvent is described by Gay-Berne (GB) molecules with parametrization ?=4.4 , ?'=20.0 , and ?=?=1 . The reduced pressure of P?=2.0 is used. Previous simulations of a pure GB system with this parametrization have shown that upon lowering the temperature, the model exhibits isotropic, nematic, smectic- A , and smectic- B /molecular crystal phases. We introduce spherical xenon solutes and adjust the energy and length scales of the GB-Xe interaction to those of the GB-GB interaction. This is done through first principles quantum chemical calculations carried out for a dimer of model mesogens as well as the mesogen-xenon complex. We preparametrize quantum chemically the Xe nuclear shielding and quadrupole coupling tensors when interacting with the model mesogen, and use the parametrization in a pairwise additive fashion in the analysis of the simulation. We present the temperature evolution of Xe129/131 shielding and Xe131 quadrupole coupling in the different phases of the GB model. From the simulations, separate isotropic and anisotropic contributions to the experimentally available total shielding can be obtained. At the experimentally relevant concentration, the presence of the xenon <span class="hlt">atoms</span> does not significantly affect the phase behavior as compared to the pure GB model. The simulations reproduce many of the characteristic experimental features of Xe NMR in real thermotropic LCs: Discontinuity in the value or trends of the shielding and quadrupole coupling at the nematic-isotropic and smectic- A -nematic phase transitions, nonlinear shift evolution in the nematic phase reflecting the behavior of the orientational order parameter, and decreasing shift in the smectic- A phase. The last observation is due to the preference of the xenon solutes to occupy the interlayer space where the density of the medium is reduced as compared to the layers. There are systematic deviations, however, in the magnitude of the shielding and its discontinuities, as well as the distribution of the solutes in the translationally ordered smectic- A phase, between the simulation and experiment. These deficiencies are believed to result from the lack of flexibility of the GB model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/15447238','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/15447238"><span id="translatedtitle"><span class="hlt">Magnetization</span> plateaus for spin-one bosons in optical lattices: Stern-Gerlach experiments with strongly correlated <span class="hlt">atoms</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Imambekov, Adilet; Lukin, Mikhail; Demler, Eugene</p> <p>2004-09-17</p> <p>We consider insulating states of spin-one bosons in optical lattices in the presence of a weak <span class="hlt">magnetic</span> field. For the states with more than one <span class="hlt">atom</span> per lattice site we find a series of quantum phase transitions between states with fixed <span class="hlt">magnetization</span> and a canted nematic phase. In the presence of a global confining potential, this unusual phase diagram leads to several novel phenomena, including the formation of <span class="hlt">magnetization</span> plateaus. We discuss how these effects can be observed using spatially resolved spin polarization measurements. PMID:15447238</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25860762','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25860762"><span id="translatedtitle">Revealing the <span class="hlt">atomic</span> site-dependent g factor within a single <span class="hlt">magnetic</span> molecule via the extended Kondo effect.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Liwei; Yang, Kai; Jiang, Yuhang; Song, Boqun; Xiao, Wende; Song, Shiru; Du, Shixuan; Ouyang, Min; Hofer, Werner A; Castro Neto, Antonio H; Gao, Hong-Jun</p> <p>2015-03-27</p> <p>The site-dependent g factor of a single <span class="hlt">magnetic</span> molecule, with intramolecular resolution, is demonstrated for the first time by low-temperature, high-<span class="hlt">magnetic</span>-field scanning tunneling microscopy of dehydrogenated Mn-phthalocyanine molecules on Au(111). This is achieved by exploring the <span class="hlt">magnetic</span>-field dependence of the extended Kondo effect at different <span class="hlt">atomic</span> sites of the molecule. Importantly, an inhomogeneous distribution of the g factor inside a single molecule is revealed. Our results open up a new route to access local spin properties within a single molecule. PMID:25860762</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvL.114l6601L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvL.114l6601L"><span id="translatedtitle">Revealing the <span class="hlt">Atomic</span> Site-Dependent g Factor within a Single <span class="hlt">Magnetic</span> Molecule via the Extended Kondo Effect</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Liwei; Yang, Kai; Jiang, Yuhang; Song, Boqun; Xiao, Wende; Song, Shiru; Du, Shixuan; Ouyang, Min; Hofer, Werner A.; Castro Neto, Antonio H.; Gao, Hong-Jun</p> <p>2015-03-01</p> <p>The site-dependent g factor of a single <span class="hlt">magnetic</span> molecule, with intramolecular resolution, is demonstrated for the first time by low-temperature, high-<span class="hlt">magnetic</span>-field scanning tunneling microscopy of dehydrogenated Mn-phthalocyanine molecules on Au(111). This is achieved by exploring the <span class="hlt">magnetic</span>-field dependence of the extended Kondo effect at different <span class="hlt">atomic</span> sites of the molecule. Importantly, an inhomogeneous distribution of the g factor inside a single molecule is revealed. Our results open up a new route to access local spin properties within a single molecule.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20717931','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20717931"><span id="translatedtitle"><span class="hlt">Atomic</span> structures and <span class="hlt">magnetism</span> in small MoS{sub 2} and WS{sub 2} clusters</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Murugan, P.; Kawazoe, Yoshiyuki; Kumar, Vijay; Ota, Norio</p> <p>2005-06-15</p> <p>First-principles calculations on stoichiometric Mo{sub n}S{sub 2n} and W{sub n}S{sub 2n} (n=1-8) clusters show that their lowest energy <span class="hlt">atomic</span> structures are dominated by a central core of metal <span class="hlt">atoms</span> while the S <span class="hlt">atoms</span> cap this core. We discuss in detail terminal, edge, and face capping of tetrahedral and octahedral Mo clusters by sulfur <span class="hlt">atoms</span> for off-stoichiometric compositions also. Capping on the terminal sites is found to be least favorable. Edge capped Mo{sub 4}S{sub 6} and face capped Mo{sub 6}S{sub 8} clusters have high symmetries and high stability among all the clusters we have studied. We find that <span class="hlt">magnetic</span> isomers are lowest in energy for some clusters though bulk MS{sub 2} (M=Mo and W) is nonmagnetic. Our results on Mo{sub 6}S{sub 8+p} (p=0-6) clusters further show that Mo{sub 6}S{sub 12} is magic with 4{mu}{sub B} <span class="hlt">magnetic</span> moment. The origin of <span class="hlt">magnetism</span> and bonding nature in these clusters is discussed. Our finding could lead to the possibility of <span class="hlt">magnetic</span> clusters of a variety of nonmagnetic transition-metal compounds and their interesting assemblies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21352270','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21352270"><span id="translatedtitle">Investigation at the <span class="hlt">atomic</span> scale of the Co spatial distribution in Zn(Co)O <span class="hlt">magnetic</span> semiconductor oxide</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Larde, R.; Talbot, E.; Vurpillot, F.; Pareige, P.; Schmerber, G.; Beaurepaire, E.; Dinia, A.; Pierron-Bohnes, V.</p> <p>2009-06-15</p> <p>A sputtered Zn{sub 0.95}Co{sub 0.05}O layer was chemically analyzed at the <span class="hlt">atomic</span> scale in order to provide an accurate image of the distribution of Co <span class="hlt">atoms</span> in the ZnO matrix. The investigation of the <span class="hlt">magnetic</span> properties shows that the as-deposited Zn{sub 0.95}Co{sub 0.05}O is ferromagnetic at room temperature. <span class="hlt">Atom</span> probe tomography reveals a homogeneous distribution of all chemical species in the layer and the absence of any Co clustering. This result proves that the ferromagnetic properties of this <span class="hlt">magnetic</span> semiconductor cannot be attributed to a secondary phase or to metallic Co precipitates within the layer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APLM....3g6102M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APLM....3g6102M"><span id="translatedtitle">A <span class="hlt">magnetic</span> <span class="hlt">atomic</span> laminate from thin film synthesis: (Mo0.5Mn0.5)2GaC</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meshkian, R.; Ingason, A. S.; Arnalds, U. B.; Magnus, F.; Lu, J.; Rosen, J.</p> <p>2015-07-01</p> <p>We present synthesis and characterization of a new <span class="hlt">magnetic</span> <span class="hlt">atomic</span> laminate: (Mo0.5Mn0.5)2GaC. High quality crystalline films were synthesized on MgO(111) substrates at a temperature of 530 C. The films display a <span class="hlt">magnetic</span> response, evaluated by vibrating sample magnetometry, in a temperature range 3-300 K and in a field up to 5 T. The response ranges from ferromagnetic to paramagnetic with change in temperature, with an acquired 5T-moment and remanent moment at 3 K of 0.66 and 0.35 ?B per metal <span class="hlt">atom</span> (Mo and Mn), respectively. The remanent moment and the coercive field (0.06 T) exceed all values reported to date for the family of <span class="hlt">magnetic</span> laminates based on so called MAX phases.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007OptSp.102..495D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007OptSp.102..495D"><span id="translatedtitle">Interrelationship between the polarization moments of different parity upon optical pumping of <span class="hlt">atoms</span> under the <span class="hlt">magnetic</span> resonance conditions: I. Experiment on the 133Cs and 4He <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dovator, N. A.; Okunevich, A. I.</p> <p>2007-04-01</p> <p>In an experiment with an optical pumping of 133Cs <span class="hlt">atoms</span> in the 62 S 1/2 ground state, the line shape of the D 2f <span class="hlt">magnetic</span> resonance signal for the transverse alignment component oscillating at a double frequency f of a radio-frequency (RF) <span class="hlt">magnetic</span> field is found to strongly depend on the polarization of pumping radiation. On passage from a linearly polarized pumping light to a circularly polarized (CP) light with a sufficiently strong RF field the ordinary three-peak line with the highest central peak transforms into a two-peak line with a minimum at the center, so that the D 2f signal line resembles the M f signal line of a transverse orientation oscillating at the RF field frequency f. This suggests that the orientation (the first-rank polarization moment (PM)) arising upon CP pumping affects the alignment (the second-rank PM); i.e., the PMs of Cs <span class="hlt">atoms</span> with different parities of their ranks become coupled. No influence of the polarization of a pumping radiation on the line shape of the D 2f signal is observed in a similar experiment with the 4He <span class="hlt">atoms</span> in the 23 S 1 metastable state.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1174115','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1174115"><span id="translatedtitle"><span class="hlt">Atomic</span> moments in Mn<sub>2</sub>CoAl thin films analyzed by X-ray <span class="hlt">magnetic</span> circular dichroism</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jamer, M. E.; Assaf, B. A.; Sterbinsky, G. E.; Arena, D. A.; Heiman, D.</p> <p>2014-12-05</p> <p>Spin gapless semiconductors are known to be strongly affected by structural disorder when grown epitaxially as thin films. The <span class="hlt">magnetic</span> properties of Mn<sub>2</sub>CoAl thin films grown on GaAs (001) substrates are investigated here as a function of annealing. This study investigates the <span class="hlt">atomic</span>-specific <span class="hlt">magnetic</span> moments of Mn and Co <span class="hlt">atoms</span> measured through X-ray <span class="hlt">magnetic</span> circular dichroism as a function of annealing and the consequent structural ordering. Results indicate that the structural distortion mainly affects the Mn <span class="hlt">atoms</span> as seen by the reduction of the <span class="hlt">magnetic</span> moment from its predicted value.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22342054','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22342054"><span id="translatedtitle">Photometric variability in a <span class="hlt">warm</span>, strongly <span class="hlt">magnetic</span> DQ white dwarf, SDSS J103655.39+652252.2</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Williams, Kurtis A.; Winget, D. E.; Montgomery, M. H.; Hermes, J. J.; Falcon, Ross E.; Winget, K. I.; Dufour, Patrick; Kepler, S. O.; Bolte, Michael; Liebert, James E-mail: jamesliebert@gmail.com</p> <p>2013-06-01</p> <p>We present the discovery of photometric variability in the DQ white dwarf SDSS J103655.39+652252.2 (SDSS J1036+6522). Time-series photometry reveals a coherent monoperiodic modulation at a period of 1115.64751(67) s with an amplitude 0.442% ± 0.024%; no other periodic modulations are observed with amplitudes ≳ 0.13%. The period, amplitude, and phase of this modulation are constant within errors over 16 months. The spectrum of SDSS J1036+6522 shows <span class="hlt">magnetic</span> splitting of carbon lines, and we use Paschen-Back formalism to develop a grid of model atmospheres for mixed carbon and helium atmospheres. Our models, while reliant on several simplistic assumptions, nevertheless match the major spectral and photometric properties of the star with a self-consistent set of parameters: T {sub eff} ≈ 15, 500 K, log g ≈ 9, log (C/He) = –1.0, and a mean <span class="hlt">magnetic</span> field strength of 3.0 ± 0.2 MG. The temperature and abundances strongly suggest that SDSS J1036+6522 is a transition object between the hot, carbon-dominated DQs and the cool, helium-dominated DQs. The variability of SDSS J1036+6522 has characteristics similar to those of the variable hot carbon-atmosphere white dwarfs (DQVs), however, its temperature is significantly cooler. The pulse profile of SDSS J1036+6522 is nearly sinusoidal, in contrast with the significantly asymmetric pulse shapes of the known <span class="hlt">magnetic</span> DQVs. If the variability in SDSS J1036+6522 is due to the same mechanism as other DQVs, then the pulse shape is not a definitive diagnostic on the absence of a strong <span class="hlt">magnetic</span> field in DQVs. It remains unclear whether the root cause of the variability in SDSS J1036+6522 and the other hot DQVs is the same.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21069875','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21069875"><span id="translatedtitle">Studies on soliton energy at critical and noncritical densities of negative ions in an inhomogeneous <span class="hlt">magnetized</span> <span class="hlt">warm</span> plasma</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Singh, Dhananjay K.; Malik, Hitendra K.</p> <p>2007-11-15</p> <p>Considering an inhomogeneous plasma having finite-temperature negative and positive ions, and the isothermal electrons in the presence of an external <span class="hlt">magnetic</span> field, the solitons at noncritical and critical densities of the negative ions are studied through Korteweg-deVries (KdV) and modified Korteweg-deVries (mKdV) equations, respectively. The compressive (rarefactive) KdV solitons are found to propagate when the negative ion concentration is less (greater) than the critical density of the negative ions. At the critical density, both the compressive and the rarefactive solitons of equal amplitudes are found to occur. The energies of the compressive KdV soliton and the mKdV solitons are found to increase and that of the rarefactive KdV soliton is found to decrease with the negative ion density. Soliton energy for both the KdV and the mKdV solitons gets lowered under the effect of stronger <span class="hlt">magnetic</span> field. The effect of ion temperature is to increase the energy of the compressive KdV soliton, whereas the energy of the rarefactive KdV soliton as well as of the mKdV solitons gets decreased. The variation of the energy with the obliqueness of the <span class="hlt">magnetic</span> field is different for the KdV and the mKdV solitons.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=global+AND+heating&id=EJ484206','ERIC'); return false;" href="http://eric.ed.gov/?q=global+AND+heating&id=EJ484206"><span id="translatedtitle">Global <span class="hlt">Warming</span>?</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Eichman, Julia Christensen; Brown, Jeff A.</p> <p>1994-01-01</p> <p>Presents information and data on an experiment designed to test whether different atmosphere compositions are affected by light and temperature during both cooling and heating. Although flawed, the experiment should help students appreciate the difficulties that researchers face when trying to find evidence of global <span class="hlt">warming</span>. (PR)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JPlPh..80...89D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JPlPh..80...89D"><span id="translatedtitle">Stability of ion acoustic solitary waves in a <span class="hlt">magnetized</span> plasma consisting of <span class="hlt">warm</span> adiabatic ions and non-thermal electrons having vortex-like velocity distribution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Das, Jayasree; Bandyopadhyay, Anup; Das, K. P.; Das</p> <p>2014-02-01</p> <p>Schamel's modified Korteweg-de Vries-Zakharov-Kuznetsov (S-ZK) equation, governing the behavior of long wavelength, weak nonlinear ion acoustic waves propagating obliquely to an external uniform static <span class="hlt">magnetic</span> field in a plasma consisting of <span class="hlt">warm</span> adiabatic ions and non-thermal electrons (due to the presence of fast energetic electrons) having vortex-like velocity distribution function (due to the presence of trapped electrons), immersed in a uniform (space-independent) and static (time-independent) <span class="hlt">magnetic</span> field, admits solitary wave solutions having a sech 4 profile. The higher order stability of this solitary wave solution of the S-ZK equation has been analyzed with the help of multiple-scale perturbation expansion method of Allen and Rowlands (Allen, M. A. and Rowlands, G. 1993 J. Plasma Phys. 50, 413; 1995 J. Plasma Phys. 53, 63). The growth rate of instability is obtained correct to the order k 2, where k is the wave number of a long wavelength plane wave perturbation. It is found that the lowest order (at the order k) instability condition is strongly sensitive to the angle of propagation (?) of the solitary wave with the external uniform static <span class="hlt">magnetic</span> field, whereas at the next order (at the order k 2) the solitary wave solutions of the S-ZK equation are unstable irrespective of ?. It is also found that the growth rate of instability up to the order k 2 for the electrons having Boltzmann distribution is higher than that of the non-thermal electrons having vortex-like distribution for any fixed ?.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016CoTPh..65...57K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016CoTPh..65...57K"><span id="translatedtitle">Roles of <span class="hlt">Atomic</span> Injection Rate and External <span class="hlt">Magnetic</span> Field on Optical Properties of Elliptical Polarized Probe Light</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karimi, R.; S. H., Asadpour; Batebi, S.; H. Rahimpour, Soleimani</p> <p>2016-01-01</p> <p>In this paper we investigate the optical properties of an open four-level tripod <span class="hlt">atomic</span> system driven by an elliptically polarized probe field in the presence of the external <span class="hlt">magnetic</span> field and compare its properties with the corresponding closed system. Our result reveals that absorption, dispersion and group velocity of probe field can be manipulated by adjusting the phase difference between the two circularly polarized components of a single coherent field, <span class="hlt">magnetic</span> field and cavity parameters i.e. the <span class="hlt">atomic</span> exit rate from cavity and <span class="hlt">atomic</span> injection rates. We show that the system can exhibit multiple electromagnetically induced transparency windows in the presence of the external <span class="hlt">magnetic</span> field. The numerical result shows that the probe field in the open system can be amplified by appropriate choice of cavity parameters, while in the closed system with introduce appropriate phase difference between fields the probe field can be enhanced. Also it is shown that the group velocity of light pulse can be controlled by external <span class="hlt">magnetic</span> field, relative phase of applied fields and cavity parameters. By changing the parameters the group velocity of light pulse changes from subluminal to superluminal light propagation and vice versa.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JETP..118..687M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JETP..118..687M"><span id="translatedtitle">Selective laser pumping of <span class="hlt">magnetic</span> sublevels in the hyperfine structure of the cesium <span class="hlt">atom</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Magunov, A. I.; Palchikov, V. G.</p> <p>2014-05-01</p> <p>The evolution of the populations of the <span class="hlt">magnetic</span> sublevels of the cesium <span class="hlt">atom</span> (133Cs isotope) in resonant laser fields with linear polarization is analyzed using the equations for the density matrix. Analytic expressions are derived for stationary populations resulting from laser-induced optical transitions on the hyperfine structure components F g = 3 ? F e = 2, 3 and F f = 4 ? F e = 3, 4 of lines D 1 (62 S 1/2 ? 62 P 1/2) and D 2 (62 S 1/2 ? 62 P 3/2) depending on the initial values of the populations. The numerical solution of the evolution equations gives the characteristic times of stabilization of the steady regime as functions of laser field intensities and detuning from optical resonance. We determine the sequences of optical transitions increasing (by more than an order of magnitude) the population of the lower sublevel 62 S 1/2 F g = 3 M = 0 of the "clock" microwave transition F g = 3 M = 0 ? F f = 4 M = 0 in the cesium frequency standard, which increases the signal intensity in the recording system by the same proportion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5182114','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5182114"><span id="translatedtitle">Shorting time of <span class="hlt">magnetically</span> insulated reflex-ion diodes from the neutral-<span class="hlt">atom</span> charge-exchange mechanism</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Strobel, G.</p> <p>1981-10-01</p> <p>In a <span class="hlt">magnetically</span> insulated diode, collision-free electrons return to the cathode and no electron current is present at the anode. Electron transport to the anode is studied in this paper. Steady-state space-charge-limited flow is assumed initially. Breakdown of ion flow occurs when static neutral <span class="hlt">atoms</span> at the anode undergo charge exchange, which results in neutral <span class="hlt">atoms</span> drifting across the diode. These are subsequently ionized by reflexing ions producing electrons trapped in Larmor orbits throughout the diode. These electrons drift to the anode via ionization and inelastic collisions with other neutral <span class="hlt">atoms</span>. Model calculations compare the effects of foil and mesh cathodes. Steady-state space-charge-limited ion current densities are calculated. The neutral <span class="hlt">atom</span> density at the cathode is determined as a function of time. The shorting time of the diode is scaled versus the electrode separation d, the diode potential V/sub 0/, the <span class="hlt">magnetic</span> field, and the initial concentration of static neutron <span class="hlt">atoms</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JMMM..385..138J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JMMM..385..138J"><span id="translatedtitle"><span class="hlt">Magnetic</span> properties of Mg12O12 nanocage doped with transition metal <span class="hlt">atoms</span> (Mn, Fe, Co and Ni): DFT study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Javan, Masoud Bezi</p> <p>2015-07-01</p> <p>Binding energy of the Mg12O12 nanocage doped with transition metals (TM=Mn, Fe, Co and Ni) in endohedrally, exohedrally and substitutionally forms were studied using density functional theory with the generalized gradient approximation exchange-correlation functional along 6 different paths inside and outside of the Mg12O12 nanocage. The most stable structures were determined with full geometry optimization near the minimum of the binding energy curves of all the examined paths inside and outside of the Mg12O12 nanocage. The results reveal that for all stable structures, the Ni <span class="hlt">atom</span> has a larger binding energy than the other TM <span class="hlt">atoms</span>. It is also found that for all complexes additional peaks contributed by TM-3d, 4s and 4p states appear in the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) gap of the host MgO cluster. The mid-gap states are mainly due to the hybridization between TM-3d, 4s and 4p orbitals and the cage π orbitals. The <span class="hlt">magnetic</span> moment of the endohedrally doped TM <span class="hlt">atoms</span> in the Mg12O12 are preserved to some extent due to the interaction between the TM and Mg12O12 nanocage, in contrast to the completely quenched <span class="hlt">magnetic</span> moment of the Fe and Ni <span class="hlt">atoms</span> in the Mg11(TM)O12 complexes. Furthermore, charge population analysis shows that charge transfer occurs from TM <span class="hlt">atom</span> to the cage for endohedrally and substitutionally doping.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/40276848','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/40276848"><span id="translatedtitle">Dynamic, self-assembled aggregates of <span class="hlt">magnetized</span>, millimeter-sized objects rotating at the liquid-air interface: Macroscopic, two-dimensional classical artificial <span class="hlt">atoms</span> and molecules</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Grzybowski, Bartosz A.; Jiang, Xingyu; Stone, Howard A.; Whitesides, George M.</p> <p>2001-07-01</p> <p>This paper describes self-assembly of millimeter-sized, <span class="hlt">magnetized</span> disks floating on a liquid-air interface, and rotating under the influence of a rotating external <span class="hlt">magnetic</span> field. Spinning of the disks results in hydrodynamic repulsion between them, while the rotating <span class="hlt">magnetic</span> field produces an average confining potential acting on all disks. The interplay between hydrodynamic and <span class="hlt">magnetic</span> interactions leads to the formation of patterns. Theoretical analysis of hydrodynamic and <span class="hlt">magnetic</span> forces indicates that the interactions in this system are similar to those acting in systems of finite numbers of particles behaving classically (''classical artificial <span class="hlt">atoms</span>''). Macroscopic artificial <span class="hlt">atoms</span> and molecules are described, and the rules governing their morphologies outlined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PhRvB..83o5404S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PhRvB..83o5404S"><span id="translatedtitle">Spin and orbital <span class="hlt">magnetism</span> of a single 3d transition-metal <span class="hlt">atom</span> doped into icosahedral coinage-metal clusters X12 (X=Cu, Ag, Au)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sargolzaei, Mahdi; Lotfizadeh, Neda</p> <p>2011-04-01</p> <p>We have demonstrated the electronic structures and <span class="hlt">magnetic</span> properties of single 3d transition metal (TM) <span class="hlt">atoms</span> encapsulated in noble metal clusters with icosahedral symmetry in the framework of relativistic density functional theory. Orbital polarization corrections have been used to obtain an upper-estimation for orbital <span class="hlt">magnetic</span> moments of all individual 3d <span class="hlt">atoms</span>. The relativistic corrections are marginally affected the spin <span class="hlt">magnetic</span> moments, whereas they induce significant orbital <span class="hlt">magnetism</span> in TM@X12 icosahedra. It is found that a superatomic picture has to be taken into account in order to explain the spin and orbital <span class="hlt">magnetism</span> induced in TM@X12 icosahedron based on the Hunds rules.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005RPPh...68.1343H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005RPPh...68.1343H"><span id="translatedtitle">Global <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Houghton, John</p> <p>2005-06-01</p> <p>'Global <span class="hlt">warming</span>' is a phrase that refers to the effect on the climate of human activities, in particular the burning of fossil fuels (coal, oil and gas) and large-scale deforestation, which cause emissions to the atmosphere of large amounts of 'greenhouse gases', of which the most important is carbon dioxide. Such gases absorb infrared radiation emitted by the Earth's surface and act as blankets over the surface keeping it warmer than it would otherwise be. Associated with this <span class="hlt">warming</span> are changes of climate. The basic science of the 'greenhouse effect' that leads to the <span class="hlt">warming</span> is well understood. More detailed understanding relies on numerical models of the climate that integrate the basic dynamical and physical equations describing the complete climate system. Many of the likely characteristics of the resulting changes in climate (such as more frequent heat waves, increases in rainfall, increase in frequency and intensity of many extreme climate events) can be identified. Substantial uncertainties remain in knowledge of some of the feedbacks within the climate system (that affect the overall magnitude of change) and in much of the detail of likely regional change. Because of its negative impacts on human communities (including for instance substantial sea-level rise) and on ecosystems, global <span class="hlt">warming</span> is the most important environmental problem the world faces. Adaptation to the inevitable impacts and mitigation to reduce their magnitude are both necessary. International action is being taken by the world's scientific and political communities. Because of the need for urgent action, the greatest challenge is to move rapidly to much increased energy efficiency and to non-fossil-fuel energy sources.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JPhB...49f5006F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JPhB...49f5006F"><span id="translatedtitle">Low frequency <span class="hlt">magnetic</span> field suppression in an <span class="hlt">atomic</span> spin co-magnetometer with a large electron <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fang, Jiancheng; Chen, Yao; Zou, Sheng; Liu, Xuejing; Hu, Zhaohui; Quan, Wei; Yuan, Heng; Ding, Ming</p> <p>2016-03-01</p> <p>In a K-Rb-21Ne co-magnetometer, the Rb electron <span class="hlt">magnetic</span> field which is experienced by the nuclear spin is about 100 times larger than that of the K in a K-3He co-magnetometer. The large electron <span class="hlt">magnetic</span> field which is neglected in the K-3He co-magnetometer coupled Bloch equations model is considered here in the K-Rb-21Ne co-magnetometer to study the low frequency <span class="hlt">magnetic</span> field suppression effect. Theoretical analysis and experimental results shows that in the K-Rb-21Ne spin co-magnetometer, not only the nuclear spin but also the large electron spin <span class="hlt">magnetic</span> field compensate the external <span class="hlt">magnetic</span> field noise. By comparison, only the 3He nuclear spins mainly compensate the external <span class="hlt">magnetic</span> field noise in a K-3He co-magnetometer. With this study, in addition to just increasing the <span class="hlt">magnetic</span> field of the nuclear spins, we can suppress the <span class="hlt">magnetic</span> field noise by increasing the density of the electron spin. We also studied how the <span class="hlt">magnetic</span> field suppression effect relates to the scale factor of the K-Rb-21Ne co-magnetometer and we compared the scale factor with that of the K-3He co-magnetometer. Lastly, we show the sensitivity of our co-magnetometer. The <span class="hlt">magnetic</span> field noise, the air density fluctuation noise and pumping power optimization are studied to improve the sensitivity of the co-magnetometer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22299801','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22299801"><span id="translatedtitle">Circuit-quantum electrodynamics with direct <span class="hlt">magnetic</span> coupling to single-<span class="hlt">atom</span> spin qubits in isotopically enriched {sup 28}Si</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tosi, Guilherme Mohiyaddin, Fahd A.; Morello, Andrea; Huebl, Hans</p> <p>2014-08-15</p> <p>Recent advances in silicon nanofabrication have allowed the manipulation of spin qubits that are extremely isolated from noise sources, being therefore the semiconductor equivalent of single <span class="hlt">atoms</span> in vacuum. We investigate the possibility of directly coupling an electron spin qubit to a superconducting resonator <span class="hlt">magnetic</span> vacuum field. By using resonators modified to increase the vacuum <span class="hlt">magnetic</span> field at the qubit location, and isotopically purified {sup 28}Si substrates, it is possible to achieve coupling rates faster than the single spin dephasing. This opens up new avenues for circuit-quantum electrodynamics with spins, and provides a pathway for dispersive read-out of spin qubits via superconducting resonators.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010PhDT.......200M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010PhDT.......200M"><span id="translatedtitle">Quantum liquid crystal phases and unconventional <span class="hlt">magnetism</span> in electronic and <span class="hlt">atomic</span> Fermi systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Munoz Fregoso, Benjamin</p> <p></p> <p>This thesis is devoted to the study of quantum liquid crystal phases in metallic systems and itinerant Fermi systems with dipole-dipole interactions. It is based on published works of Refs. [65, 193, 68, 67, 66]. In the first part of the Thesis, I present the construction of a generalization of the McMillan-de Gennes theory of nematic-smectic thermal phase transition of classical liquid crystals to describe an analogous quantum phase transition in metallic systems. This theory qualitatively can also describe similar quantum phase transitions in high Tc superconductors. Recent experimental advances in cooling <span class="hlt">atoms</span> with large electric or <span class="hlt">magnetic</span> moment[125] make possible the study of novel quantum phases that arise due to the anisotropic and long-range nature of the dipole-dipole interactions. In the next part of the Thesis I present a Landau Fermi liquid theory of one-component Fermi systems with electric or <span class="hlt">magnetic</span> dipolar interactions. I use this theory to construct an order parameter theory and predict elongated Fermi surface (FS) along the polarization axis. I calculate the temperature and interaction dependence of FS distortions. For a two-component system with <span class="hlt">magnetic</span> dipole-dipole interactions I predict the existence of "spin textures" in momentum space and of prolate/oblate deformed FS's. This constitutes a new phase of matter I called ferronematic. Possible observation of this phase in ultracold Fermi gases with large <span class="hlt">magnetic</span> moments such as 163Dy are discussed. The stability of Fermi gases under attractive interactions at unitarity was also studied. I now briefly summarize the content of this thesis. Chapter 2 is based on Ref. [65]. I present a unified overview, from the mean-field to the unitarity regime, of the stability of a trapped Fermi gas with short range attractive interactions. Unlike in a system of bosons, a Fermi gas is always stable in these regimes, no matter how large the particle number. However, when the interparticle spacing becomes comparable to the range of the interatomic interactions, instability is not precluded. Chapter 3 is based on Ref. [193]. I discuss the quantum phase transition between a quantum nematic metallic state to an electron metallic smectic state in terms of an order-parameter theory coupled to fermionic quasiparticles. Both commensurate and incommensurate smectic (or stripe) cases are studied. Close to the quantum critical point (QCP), the spectrum of fluctuations of the nematic phase has low-energy fluctuating stripes. I study the quantum critical behavior and find evidence that, contrary to the classical case, the gauge-type of coupling between the nematic and smectic is irrelevant at this QCP. The collective modes of the electron smectic (or stripe) phase are also investigated. The effects of the low-energy bosonic modes on the fermionic quasiparticles are studied perturbatively. I find that at the nematic-smectic critical point, due to the critical smectic fluctuations, the dynamics of the fermionic quasiparticles near several points on the Fermi surface, around which it is reconstructed, are not governed by a Landau Fermi liquid theory. On the other hand, the quasiparticles in the smectic phase exhibit Fermi liquid behavior. I also present a detailed analysis of the dynamical susceptibilities in the electron nematic phase close to this QCP (the fluctuating stripe regime) and in the electronic smectic phase. Chapter 4 is based on Ref. [68]. I demonstrate the possibility of a spontaneous symmetry breaking biaxial phase in these systems, which may be realized in, e.g., gases of ultracold polar molecules or strongly <span class="hlt">magnetic</span> <span class="hlt">atoms</span>. This biaxial nematic phase is manifest in a spontaneous distortion of the Fermi surface perpendicular to the axis of polarization. I describe these dipolar interaction induced phases using Landau Fermi liquid theory. Chapter 5 is based on Ref. [67]. I show that a homogeneous two-component Fermi gas with long range dipolar and short-range isotropic interactions has a ferronematic phase for suitable values of the dipolar and short-r</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19790016567&hterms=Atomic+weights&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3D%2528Atomic%2Bweights%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19790016567&hterms=Atomic+weights&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3D%2528Atomic%2Bweights%2529"><span id="translatedtitle">Shielding of longitudinal <span class="hlt">magnetic</span> fields with thin, closely, spaced concentric cylindrical shells with applications to <span class="hlt">atomic</span> clocks</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wolf, S. A.; Gubser, D. U.; Cox, J. E.</p> <p>1978-01-01</p> <p>A general formula is given for the longitudinal shielding effectiveness of N closed concentric cylinders. The use of these equations is demonstrated by application to the design of <span class="hlt">magnetic</span> shields for hydrogen maser <span class="hlt">atomic</span> clocks. Examples of design tradeoffs such as size, weight, and material thickness are discussed. Experimental results on three sets of shields fabricated by three manufacturers are presented. Two of the sets were designed employing the techniques described. Agreement between the experimental results and the design calculations is then demonstrated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvA..92f2701T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvA..92f2701T"><span id="translatedtitle">Ultracold <span class="hlt">magnetically</span> tunable interactions without radiative-charge-transfer losses between Ca+, Sr+, Ba+, and Yb+ ions and Cr <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tomza, Michał</p> <p>2015-12-01</p> <p>The Ca+, Sr+, Ba+, and Yb+ ions immersed in an ultracold gas of the Cr <span class="hlt">atoms</span> are proposed as experimentally feasible heteronuclear systems in which ion-<span class="hlt">atom</span> interactions at ultralow temperatures can be controlled with <span class="hlt">magnetically</span> tunable Feshbach resonances without charge transfer and radiative losses. Ab initio techniques are applied to investigate electronic-ground-state properties of the (CaCr)+, (SrCr)+, (BaCr)+, and (YbCr)+ molecular ions. The potential energy curves, permanent electric dipole moments, and static electric dipole polarizabilities are computed. The spin-restricted open-shell coupled-cluster method restricted to single, double, and noniterative triple excitations and the multireference configuration-interaction method restricted to single and double excitations are employed. The scalar relativistic effects are included within the small-core energy-consistent pseudopotentials. The leading long-range induction and dispersion interaction coefficients are also reported. Finally, <span class="hlt">magnetic</span> Feshbach resonances between the Ca+, Sr+, Ba+, and Yb+ ions interacting with the Cr <span class="hlt">atoms</span> are analyzed. The present proposal opens the way towards robust quantum simulations and computations with ultracold ion-<span class="hlt">atom</span> systems free of radiative charge-transfer losses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6743294','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6743294"><span id="translatedtitle"><span class="hlt">Atomization</span> characteristics and direct determination of manganese and magnesium in biological samples using a <span class="hlt">magnetically</span> altered thin-film plasma</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Brewer, S.W. Jr.; Sacks, R.D.</p> <p>1988-09-01</p> <p>A <span class="hlt">magnetic</span> field with peak value of 3.7 kG is used to improve the <span class="hlt">atomization</span> characteristics of an electrically vaporized thin-film plasma for the direct determination of Mg and Mn in solid biological materials. Plasmas are generated by high-current capacitive discharges through 350-..mu..g Ag or Au thin films formed on polypropylene substrates. Radiation intensity vs time plots are compared with and without the <span class="hlt">magnetic</span> field for the NBS materials bovine liver, oyster tissue, orchard leaves, citrus leaves, tomato leaves, and pine needles. Analytical standard for Mg are prepared from suspensions of MgO powder, and standards for Mn are prepared from aqueous solutions of Mn(NO/sub 3/)/sub 2/ or MnSO/sub 4/. Analytical accuracy usually is improved with the presence of the <span class="hlt">magnetic</span> field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4271256','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4271256"><span id="translatedtitle">Reversible switching of <span class="hlt">magnetic</span> states by electric fields in nitrogenized-divacancies graphene decorated by tungsten <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ge, Gui-Xian; Sun, Hai-Bing; Han, Yan; Song, Feng-Qi; Zhao, Ji-Jun; Wang, Guang-Hou; Wan, Jian-Guo</p> <p>2014-01-01</p> <p><span class="hlt">Magnetic</span> graphene-based materials have shown great potential for developing high-performance electronic devices at sub-nanometer such as spintronic data storage units. However, a significant reduction of power consumption and great improvement of structural stability are needed before they can be used for actual applications. Based on the first-principles calculations, here we demonstrate that the interaction between tungsten <span class="hlt">atoms</span> and nitrogenized-divacancies (NDVs) in the hybrid W@NDV-graphene can lead to high stability and large <span class="hlt">magnetic</span> anisotropy energy (MAE). More importantly, reversible switching between different <span class="hlt">magnetic</span> states can be implemented by tuning the MAE under different electric fields, and very low energy is consumed during the switching. Such controllable switching of <span class="hlt">magnetic</span> states is ascribed to the competition between the tensile stain and orbital <span class="hlt">magnetic</span> anisotropy, which originates from the change in the occupation number of W-5d orbitals under the electric fields. Our results provide a promising avenue for developing high-density <span class="hlt">magnetic</span> storage units or multi-state logical switching devices with ultralow power at sub-nanometer. PMID:25524662</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004PhDT........21X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004PhDT........21X"><span id="translatedtitle">A continuous controlled cold beam of rubidium <span class="hlt">atoms</span> for loading a <span class="hlt">magnetic</span> waveguide</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xiao, Yanhong</p> <p></p> <p>Guided <span class="hlt">atom</span> gyroscopes have the potential of higher sensitivity than their free space counterparts. The first experiment step is to generate a cold source suitable for loading such waveguide-based <span class="hlt">atom</span> gyroscopes. We developed a cold continuous Rubidium <span class="hlt">atomic</span> beam for this application. A two-dimensional magneto-optic trap plus the longitudinal molasses is used to capture the <span class="hlt">atoms</span> from the vapor cell, and an additional pushing beam unloads the <span class="hlt">atoms</span> to the beam and controls the velocity of the beam. The beam velocity can vary from 2 m/s to 20 m/s. We studied the beam properties at various velocities, background pressures, laser intensities etc. An optimized flux of 8 x 10 9 <span class="hlt">atoms</span>/s is achieved at a background Rb pressure of 5 x 10-7 mbar with beam velocity of 15 m/s, velocity spread of about 3 m/s and divergence of 14 mrad.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16122294','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16122294"><span id="translatedtitle">Relativistic dynamics of half-spin particles in a homogeneous <span class="hlt">magnetic</span> field: an <span class="hlt">atom</span> with nucleus of spin 12.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Misra, Anirban; Datta, Sambhu N</p> <p>2005-08-01</p> <p>An investigation of the relativistic dynamics of N+1 spin-12 particles placed in an external, homogeneous <span class="hlt">magnetic</span> field is carried out. The system can represent an <span class="hlt">atom</span> with a fermion nucleus and N electrons. Quantum electrodynamical interactions, namely, projected Briet and <span class="hlt">magnetic</span> interactions, are chosen to formulate the relativistic Hamiltonian. The quasi-free-particle picture is retained here. The total pseudomomentum is conserved, and its components are distinct when the total charge is zero. Therefore, the center-of-mass motion can be separated from the Hamiltonian for a neutral (N+1)-fermion system, leaving behind a unitarily transformed, effective Hamiltonian H(0) at zero total pseudomomentum. The latter operator represents the complete relativistic dynamics in relative coordinates while interaction is chosen through order alpha4mc2. Each one-particle part in the effective Hamiltonian can be brought to a separable form for positive- and negative-energy states by replacing the odd operator in it through two successive unitary transformations, one due to Tsai [Phys. Rev. D 7, 1945 (1973)] and the other due to Weaver [J. Math. Phys. 18, 306 (1977)]. Consequently, the projector changes and the interaction that involves the concerned particle also becomes free from the corresponding odd operators. When this maneuver is applied only to the nucleus, and the non-Hermitian part of the transformed interaction is removed by another unitary transformation, a familiar form of the <span class="hlt">atomic</span> relativistic Hamiltonian H(<span class="hlt">atom</span>) emerges. This operator is equivalent to H(0). A good Hamiltonian for relativistic quantum chemical calculations, H(Qchem), is obtained by expanding the nuclear part of the <span class="hlt">atomic</span> Hamiltonian through order alpha4mc2 for positive-energy states. The operator H(Qchem) is obviously an approximation to H(<span class="hlt">atom</span>). When the same technique is used for all particles, and subsequently the non-Hermitian terms are removed by suitable unitary transformations, one obtains a Hamiltonian H(T) that is equivalent to H(<span class="hlt">atom</span>) but is in a completely separable form. As the semidiscrete eigenvalues and eigenfunctions of the one-particle parts are known, the completely separable Hamiltonian can be used in computation. A little more effort leads to the derivation of the correct <span class="hlt">atomic</span> Hamiltonian in the nonrelativistic limit, H(nonrel). The operator H(nonrel) is an approximation to H(T). It not only retains the relativistic and radiative effects, but also directly exhibits the phenomena of electron paramagnetic resonance and nuclear <span class="hlt">magnetic</span> resonance. PMID:16122294</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997PhRvB..5511422H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997PhRvB..5511422H"><span id="translatedtitle">Thickness dependence of the total <span class="hlt">magnetic</span> moment per <span class="hlt">atom</span> in the Cu/Ni/Cu/Si(001) system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hope, S.; Lee, J.; Rosenbusch, P.; Lauhoff, G.; Bland, J. A. C.; Ercole, A.; Bucknall, D.; Penfold, J.; Lauter, H. J.; Lauter, V.; Cubitt, R.</p> <p>1997-05-01</p> <p>Systematic measurements of the <span class="hlt">magnetic</span> moment per Ni <span class="hlt">atom</span> in Cu/Ni/Cu/Si(001) structures have been made using polarized neutron reflection (PNR) for Ni thicknesses in the range 30 <t<400 at room temperature. We find a dramatic reduction in the <span class="hlt">magnetic</span> moment per <span class="hlt">atom</span> for t<100 and near bulk values above 100 . These results are corroborated by alternating gradient magnetometer measurements on the same samples. A Cu/Ni-wedge/Cu/Si(001) structure with 30 <t<150 was studied using <span class="hlt">magnetic</span> circular x-ray dichroism (MCXD), polar magneto-optical Kerr effect (MOKE), and reflection high-energy electron diffraction (RHEED) in order to estimate the variation in the values of <Lz>, <Sz>, perpendicular anisotropy strength, and surface in-plane Ni lattice constant, respectively, during epitaxial growth. RHEED measurements show that the in-plane lattice constant falls by 1.7% in the Ni thickness range 30 <t<90 . The MCXD measurements reveal the same trend for <Lz>, <Sz>, and total moment per <span class="hlt">atom</span> versus Ni thickness as found for the total moment by PNR. Polar MOKE measurements confirmed the transition from a perpendicular easy axis towards an in-plane <span class="hlt">magnetic</span> easy axis as has already been extensively studied in the literature. Comparison of the PNR results with RHEED measurements reveal a striking correlation between the increase of in-plane strain and reduction in <span class="hlt">magnetic</span> moment per <span class="hlt">atom</span> with decreasing Ni thickness. While a direct strain-induced variation of the moment based on bulk phase calculations cannot account for the magnitude of the moment variations we observe, we show that the results cannot be attributed to sample contamination, interdiffusion, or a reduction of the Curie temperature with decreasing Ni thickness. Furthermore, the presence of a <span class="hlt">magnetically</span> dead layer in the samples is not consistent with the PNR results. The strong moment variation partially explains the large thickness range for which perpendicular anisotropy is observed in this system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996JPhB...29.1063S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996JPhB...29.1063S"><span id="translatedtitle">Molecular-orbital treatment of electron capture in an external <span class="hlt">magnetic</span> field: collisions of ? ions with H <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Suzuki, S.; Shimakura, N.; Kimura, M.</p> <p>1996-03-01</p> <p>A semiclassical close-coupling equation is formulated for the electron-capture process in ion - <span class="hlt">atom</span> collisions under the influence of an external <span class="hlt">magnetic</span> field. The direction of the <span class="hlt">magnetic</span> field is chosen to be parallel to an initial velocity vector of a projectile. As we deal with the case for the <span class="hlt">magnetic</span> field strength less than the critical field strength 0953-4075/29/5/015/img7, the second- and higher-order terms for the <span class="hlt">magnetic</span> field are neglected. Eigenfunctions in zero <span class="hlt">magnetic</span> field are employed as a basis set for expansion. The equation obtained is the same in structure as that at zero <span class="hlt">magnetic</span> field except that the relative velocity v is replaced by the scaled velocity 0953-4075/29/5/015/img8. Effects due to the <span class="hlt">magnetic</span> field are: (i) dynamical couplings, similar to rotational couplings and (ii) the Zeeman splitting of energies. The phase factor due to the gauge transformation is similar in form to the electron-translation factor. We apply this close-coupling equation to a study of electron-capture processes in a singlet 0953-4075/29/5/015/img9 system at 0953-4075/29/5/015/img10, for which the zero-field results have been reported earlier (Shimakura et al 1993). Calculated results show that the total electron-capture cross section increases by about 30% at the <span class="hlt">magnetic</span> field 0953-4075/29/5/015/img11 T compared to that at zero <span class="hlt">magnetic</span> field at collision energy E = 122.5 eV/amu. At low collision energies below 500 eV/amu, the effect of the <span class="hlt">magnetic</span> field becomes dominant over that of rotational couplings at 0953-4075/29/5/015/img12. Because the <span class="hlt">magnetic</span> field removes the degeneracy of electronic energies for 0953-4075/29/5/015/img13 (and 0953-4075/29/5/015/img14) states by the Zeeman effect, transition probabilities for 0953-4075/29/5/015/img15 and 0953-4075/29/5/015/img16 (and also 0953-4075/29/5/015/img17 and 0953-4075/29/5/015/img18) states differ significantly. The transition probabilities oscillate with time even if the collision pair separates considerably, particularly for 0953-4075/29/5/015/img19 and 0953-4075/29/5/015/img20 states because of the <span class="hlt">magnetic</span> field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=atomic&id=EJ1040109','ERIC'); return false;" href="http://eric.ed.gov/?q=atomic&id=EJ1040109"><span id="translatedtitle">A Simple Demonstration of <span class="hlt">Atomic</span> and Molecular Orbitals Using Circular <span class="hlt">Magnets</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Chakraborty, Maharudra; Mukhopadhyay, Subrata; Das, Ranendu Sekhar</p> <p>2014-01-01</p> <p>A quite simple and inexpensive technique is described here to represent the approximate shapes of <span class="hlt">atomic</span> orbitals and the molecular orbitals formed by them following the principles of the linear combination of <span class="hlt">atomic</span> orbitals (LCAO) method. Molecular orbitals of a few simple molecules can also be pictorially represented. Instructors can employ the…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Atomic+AND+structure&pg=4&id=EJ1040109','ERIC'); return false;" href="http://eric.ed.gov/?q=Atomic+AND+structure&pg=4&id=EJ1040109"><span id="translatedtitle">A Simple Demonstration of <span class="hlt">Atomic</span> and Molecular Orbitals Using Circular <span class="hlt">Magnets</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Chakraborty, Maharudra; Mukhopadhyay, Subrata; Das, Ranendu Sekhar</p> <p>2014-01-01</p> <p>A quite simple and inexpensive technique is described here to represent the approximate shapes of <span class="hlt">atomic</span> orbitals and the molecular orbitals formed by them following the principles of the linear combination of <span class="hlt">atomic</span> orbitals (LCAO) method. Molecular orbitals of a few simple molecules can also be pictorially represented. Instructors can employ the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001PhDT.......119K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001PhDT.......119K"><span id="translatedtitle">Probing quantum confinement at the <span class="hlt">atomic</span> scale with optically detected nuclear <span class="hlt">magnetic</span> resonance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kempf, James G.</p> <p>2001-09-01</p> <p>Near-band-gap circularly polarized excitation in III-V semiconductors provides spin-polarized electrons that transfer spin order to lattice nuclei via fluctuations in the contact hyperfine interaction. This process of optical nuclear polarization and the complementary technique of optical detection of nuclear <span class="hlt">magnetic</span> resonance (NMR) provide extreme sensitivity enhancement and spatial selectivity in structured samples, enabling collection of NMR spectra from samples such as single quantum wells or dots containing as few as 105 nuclei. Combining these advances with novel techniques for high spectral resolution, we have probed quantum-confined electronic states near the interface of a single epitaxially grown Al1-x As/GaAs (x = 0.36) heterojunction. Using a novel strategy that we refer to as POWER (p&barbelow;erturbations o&barbelow;bserved w&barbelow;ith e&barbelow;nhanced ?esolution) NMR, multiple-pulse time suspension is synchronized with bandgap optical irradiation to reveal spectra of effective spin Hamiltonians that are differences between those of the occupied and unoccupied photoexcited electronic state. The underlying NMR linewidth is reduced by three orders of magnitude in these experiments, enabling resolution of an asymmetric line shape due to light-induced hyperfine interactions. The results are successfully fit with the coherent nuclear spin evolution and relaxation theoretically expected for sites distributed over the volume of an electronic excitation weakly localized at a point defect. This analysis establishes a one-to-one relationship, which can be used to follow nuclear spin diffusion, between optical Knight shift and the radial position of lattice nuclei. We have also introduced POWER NMR techniques to characterize the change in electric field associated with cycling from light-on to light-off states via a linear quadrupole Stark effect (LQSE) of the nuclear spins. Simulations of these NMR spectra in terms of the radial electric fields of either donor-bound electrons or excitons indicate differences, where the bound-exciton model provides a significantly better fit to the data. The same spin physics enabled our measurement of the heterojunction interfacial field, which we find to be less than 1.3 kV/cm at the sites responsible for optical NMR. Other simulations show the promise of optical NMR as a tool in future studies aimed at <span class="hlt">atomic</span>-level characterization of quantum-confined systems such as quantum dots and wells.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22271318','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22271318"><span id="translatedtitle">Effects of the interplay between <span class="hlt">atomic</span> and <span class="hlt">magnetic</span> order on the properties of metamagnetic Ni-Co-Mn-Ga shape memory alloys</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Seguí, C.</p> <p>2014-03-21</p> <p>Ni-Co-Mn-Ga ferromagnetic shape memory alloys show metamagnetic behavior for a range of Co contents. The temperatures of the structural and <span class="hlt">magnetic</span> transitions depend strongly on composition and <span class="hlt">atomic</span> order degree, in such a way that combined composition and thermal treatment allows obtaining martensitic transformation between any <span class="hlt">magnetic</span> state of austenite and martensite. This work presents a detailed analysis of the effect of <span class="hlt">atomic</span> order on Ni-Co-Mn-Ga alloys through the evolution of structural and <span class="hlt">magnetic</span> transitions after quench from high temperatures and during post-quest ageing. It is found that the way in which the <span class="hlt">atomic</span> order affects the martensitic transformation temperatures and entropy depends on the <span class="hlt">magnetic</span> order of austenite and martensite. The results can be explained assuming that improvement of <span class="hlt">atomic</span> order decreases the free energy of the structural phases according to their <span class="hlt">magnetic</span> order. However, it is assumed in this work that changes in the slope—that is, the entropy—of the Gibbs free energy curves are also decisive to the stability of the two-phase system. The experimental transformation entropy values have been compared with a phenomenological model, based on a Bragg–Williams approximation, accounting for the <span class="hlt">magnetic</span> contribution. The excellent agreement obtained corroborates the <span class="hlt">magnetic</span> origin of changes in transformation entropy brought about by <span class="hlt">atomic</span> ordering.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22066282','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22066282"><span id="translatedtitle"><span class="hlt">Magnetic</span> transport apparatus for the production of ultracold <span class="hlt">atomic</span> gases in the vicinity of a dielectric surface</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Haendel, S.; Marchant, A. L.; Wiles, T. P.; Hopkins, S. A.; Cornish, S. L.</p> <p>2012-01-15</p> <p>We present an apparatus designed for studies of <span class="hlt">atom</span>-surface interactions using quantum degenerate gases of {sup 85}Rb and {sup 87}Rb in the vicinity of a room temperature dielectric surface. The surface to be investigated is a super-polished face of a glass Dove prism mounted in a glass cell under ultra-high vacuum. To maintain excellent optical access to the region surrounding the surface, <span class="hlt">magnetic</span> transport is used to deliver ultracold <span class="hlt">atoms</span> from a separate vacuum chamber housing the magneto-optical trap (MOT). We present a detailed description of the vacuum apparatus highlighting the novel design features; a low profile MOT chamber and the inclusion of an obstacle in the transport path. We report the characterization and optimization of the <span class="hlt">magnetic</span> transport around the obstacle, achieving transport efficiencies of 70% with negligible heating. Finally, we demonstrate the loading of a hybrid optical-<span class="hlt">magnetic</span> trap with {sup 87}Rb and the creation of Bose-Einstein condensates via forced evaporative cooling close to the dielectric surface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009JaJAP..48hJB05Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009JaJAP..48hJB05Y"><span id="translatedtitle">Nanoscale Investigation of Au Islands-Ni Film Interactions by <span class="hlt">Magnetic</span>-Force-Controlled <span class="hlt">Atomic</span> Force Microscopy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yamamoto, Shin-ichi; Yamada, Hirofumi</p> <p>2009-08-01</p> <p>The study of metal-metal interactions is both interesting and of technological importance for various thin-film structures. We carried out surface elemental analysis of several metal-plated films using <span class="hlt">magnetic</span>-force-controlled <span class="hlt">atomic</span> force microscopy (MFC-AFM) to evaluate the quality of wireless bondings and the films themselves. We reached the following two conclusions. First, the stiffness of the two types of plated metal film can be differentiated by MFC-AFM, whereby the difference in stiffness between the plated metal films can be imaged. Simultaneous imaging of the surface properties and stiffness of the samples produced by wet processes can be achieved at high resolution. Secondly, the Ni <span class="hlt">atoms</span> that diffused to the Au-plated film surface annealed at 180 C for 5 min can also be imaged by MFC-AFM. The relationship of these metal-metal interactions to the electronic packaging are discussed in this paper.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110014745','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110014745"><span id="translatedtitle"><span class="hlt">Atom</span> Skimmers and <span class="hlt">Atom</span> Lasers Utilizing Them</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hulet, Randall; Tollett, Jeff; Franke, Kurt; Moss, Steve; Sackett, Charles; Gerton, Jordan; Ghaffari, Bita; McAlexander, W.; Strecker, K.; Homan, D.</p> <p>2005-01-01</p> <p><span class="hlt">Atom</span> skimmers are devices that act as low-pass velocity filters for <span class="hlt">atoms</span> in thermal <span class="hlt">atomic</span> beams. An <span class="hlt">atom</span> skimmer operating in conjunction with a suitable thermal <span class="hlt">atomic</span>-beam source (e.g., an oven in which cesium is heated) can serve as a source of slow <span class="hlt">atoms</span> for a magneto-optical trap or other apparatus in an <span class="hlt">atomic</span>-physics experiment. Phenomena that are studied in such apparatuses include Bose-Einstein condensation of <span class="hlt">atomic</span> gases, spectra of trapped <span class="hlt">atoms</span>, and collisions of slowly moving <span class="hlt">atoms</span>. An <span class="hlt">atom</span> skimmer includes a curved, low-thermal-conduction tube that leads from the outlet of a thermal <span class="hlt">atomic</span>-beam source to the inlet of a magneto-optical trap or other device in which the selected low-velocity <span class="hlt">atoms</span> are to be used. Permanent rare-earth <span class="hlt">magnets</span> are placed around the tube in a yoke of high-<span class="hlt">magnetic</span>-permeability material to establish a quadrupole or octupole <span class="hlt">magnetic</span> field leading from the source to the trap. The <span class="hlt">atoms</span> are attracted to the locus of minimum <span class="hlt">magnetic</span>-field intensity in the middle of the tube, and the gradient of the <span class="hlt">magnetic</span> field provides centripetal force that guides the <span class="hlt">atoms</span> around the curve along the axis of the tube. The threshold velocity for guiding is dictated by the gradient of the <span class="hlt">magnetic</span> field and the radius of curvature of the tube. <span class="hlt">Atoms</span> moving at lesser velocities are successfully guided; faster <span class="hlt">atoms</span> strike the tube wall and are lost from the beam.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20718205','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20718205"><span id="translatedtitle">Splitting of an electromagnetically induced transparency window of rubidium <span class="hlt">atoms</span> in a static <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wei Xiaogang; Wu Jinhui; Sun Guixia; Shao Zhuang; Kang Zhihui; Jiang Yun; Gao Jinyue</p> <p>2005-08-15</p> <p>We study the phenomenon of electromagnetically induced transparency (EIT) of {sup 87}Rb vapor at the temperature of 325 K in a <span class="hlt">magnetic</span> field. Two linearly polarized orthogonal laser fields act on two dipole-allowed transitions of the D1 line of {sup 87}Rb in the {lambda} configuration, respectively. In the absence of <span class="hlt">magnetic</span> fields, we observe a wide EIT window with the contrast of about 66% while when the <span class="hlt">magnetic</span> field is applied, the wide EIT window is split into three or four narrower subwindows with contrasts of 32% or 16% due to the lifting of <span class="hlt">magnetic</span> sublevels' degeneracy. The number of EIT subwindows depends on the <span class="hlt">magnetic</span> field orientation. Our theoretical simulations and analysis are in good agreement with the experimental results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22093418','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22093418"><span id="translatedtitle"><span class="hlt">Magnetic</span>-field effects in transitions of X Li molecules (X: even isotopes of group II <span class="hlt">atoms</span>)</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gopakumar, Geetha; Abe, Minori; Hada, Masahiko; Kajita, Masatoshi</p> <p>2011-10-15</p> <p>We analyze the Zeeman shift in the (v,N)=(0,0){yields}(1,0) transition frequency of X Li molecules (X: even isotopes of group II <span class="hlt">atoms</span>), which is of interest in metrology. The Zeeman shift in the transition frequency between stretching states is found to be less than 1 mHz with a <span class="hlt">magnetic</span> field of 1 G. X {sup 6}Li molecules are more advantageous than X {sup 7}Li molecules for measuring the transition frequency without the Zeeman shift because of the smaller g factor of the Li nuclear spin.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22350804','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22350804"><span id="translatedtitle">Temperature and bias-voltage dependence of <span class="hlt">atomic</span>-layer-deposited HfO{sub 2}-based <span class="hlt">magnetic</span> tunnel junctions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Fabretti, Savio; Zierold, Robert; Nielsch, Kornelius; Voigt, Carmen; Ronning, Carsten; Peretzki, Patrick; Seibt, Michael; Thomas, Andy</p> <p>2014-09-29</p> <p><span class="hlt">Magnetic</span> tunnel junctions with HfO{sub 2} tunnel barriers were prepared through a combination of magnetron sputtering and <span class="hlt">atomic</span> layer deposition. We investigated the tunneling transport behavior, including the tunnel magnetoresistance ratio and the current-voltage characteristics between room temperature and 2 K. Here, we achieved a tunneling magneto resistance ratio of 10.3% at room temperature and 19.3% at 2 K. Furthermore, we studied the bias-voltage and temperature dependencies and compared the results with those of commonly used alumina- and magnesia-based <span class="hlt">magnetic</span> tunnel junctions. We observed a polycrystalline/amorphous electrode-barrier system via high-resolution transmission electron microscopy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhyE...73..257Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhyE...73..257Z"><span id="translatedtitle">The electronic and <span class="hlt">magnetic</span> properties of B-doping Stone-Wales defected graphene decorated with transition-metal <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhou, Qingxiao; Fu, Zhibing; Wang, Chaoyang; Tang, Yongjian; Zhang, Hong; Yuan, Lei; Yang, Xi</p> <p>2015-09-01</p> <p>The geometry, electronic, and <span class="hlt">magnetic</span> properties of transition-metal (TM) <span class="hlt">atoms</span> adsorbed on the Stone-Wales (SW) defected graphene with or without B-doped were investigated by the first-principles density functional theory (DFT), aiming to study the effect of a combination of B-dopant and SW-defect on the adsorption of TM-adatoms on graphene. It was found that the introducing of B-dopant enhanced the adsorption of TM-adatoms, while it hardly affected the electronic structure of defected graphene. Meanwhile, the <span class="hlt">magnetic</span> properties of the adsorption systems were mainly contributed by the 3d orbitals of TM-adatoms. We hope our results will be useful for applications in the designing of devices based on graphene.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6881570','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6881570"><span id="translatedtitle">Direct <span class="hlt">atomic</span> emission determination of some trace metals in solid powder samples with a <span class="hlt">magnetically</span> tailored capacitive discharge plasma</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Albers, D.; Sacks, R.</p> <p>1987-02-15</p> <p>A <span class="hlt">magnetic</span> field is used to alter the structure of the plasma produced by the electrical vaporization of a 40 nm thick, 350 ..mu..g silver film. The films are vacuum deposited on plastic substrates. The sample, as a particle suspension in isopropyl alcohol, is applied to the film surface and vaporized along with the film by interaction with the hot plasma gases. A <span class="hlt">magnetic</span> field of a few kilogauss results in a significant drift motion of the plasma. This reduces the rate of plasma expansion, improves positional stability, and dramatically increases the rate of sample <span class="hlt">atomization</span>. In addition, continuum background radiation is more localized near the substrate surface, and increased line-to-background ratios are obtained if this region is masked. General analytical features of the plasma are discussed and analytical data presented for several NBS solid powder reference materials. Relative errors typically are in the 5-10% range.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009PhDT.......258G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009PhDT.......258G"><span id="translatedtitle"><span class="hlt">Atomic</span> scale design and control of cation distribution in hexagonal ferrites for passive and tunable microwave <span class="hlt">magnetic</span> device applications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Geiler, Anton L.</p> <p></p> <p>A vast body of knowledge on the structure and properties of hexagonal ferrites has been accumulated in the last sixty years driven in part by the technological significance of these materials in diverse applications, such as permanent <span class="hlt">magnets</span>, microwave devices, and <span class="hlt">magnetic</span> recording media. In this work, the Alternating Target Laser Ablation Deposition (ATLAD) technique is applied in the growth of epitaxial hexagonal ferrite films. As a result, unique <span class="hlt">magnetic</span> properties, including 50 degrees increase in the Neel temperature and 20% increase in the saturation <span class="hlt">magnetization</span> compared to conventionally prepared materials, are realized by controlling the cation distribution at the <span class="hlt">atomic</span> scale. Lowest energy distributions resulting from the localization of Mn cations in the spinel block of the hexagonal M-type unit cell were theoretically determined by ab-initio calculations. ATLAD deposition routine was designed to deposit epitaxial thin films with the cation distribution identified by ab-initio calculations. The films were fully characterized in terms of composition, crystal structure, surface morphology, static and dynamic <span class="hlt">magnetic</span> properties, and cation distribution. Enhanced <span class="hlt">magnetic</span> moment (+20%) and Neel temperature (+50 K) were measured in the films. These improved <span class="hlt">magnetic</span> properties were correlated with the occupation and valence of specific interstitial sites by Mn cations, in good agreement with theoretical predictions. The localization of Mn cations in 4fIV and 12k sublattices has fundamentally modified superexchange interactions in the unit cell, as confirmed by spinwave resonance measurements. A novel approach to the design of tunable microwave devices based on hexagonal and cubic ferrites by taking advantage of the magnetoelectric effect is presented. The proposed planar and compact devices, including phase shifters and filters, were designed in microstrip geometry with low <span class="hlt">magnetic</span> bias field requirements. The devices were designed and simulated using commercial finite element software (Ansoft HFSS) for cubic ferrites and specially developed numerical method based on Galerkin's approach in spectral domain for highly anisotropic hexagonal ferrites. Prototypes were fabricated using standard photolithographic techniques. The active tuning of the devices was realized using voltage controlled <span class="hlt">magnetic</span> fringe fields emanating from stress coupled magnetoelectric heterostructures. The proposed approach has the potential benefits of drastically reduced power consumption, improved response time, as well as reduced size, cost, and weight.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26905782','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26905782"><span id="translatedtitle"><span class="hlt">Atomic</span>-Scale Structure and Local Chemistry of CoFeB-MgO <span class="hlt">Magnetic</span> Tunnel Junctions.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Zhongchang; Saito, Mitsuhiro; McKenna, Keith P; Fukami, Shunsuke; Sato, Hideo; Ikeda, Shoji; Ohno, Hideo; Ikuhara, Yuichi</p> <p>2016-03-01</p> <p><span class="hlt">Magnetic</span> tunnel junctions (MTJs) constitute a promising building block for future nonvolatile memories and logic circuits. Despite their pivotal role, spatially resolving and chemically identifying each individual stacking layer remains challenging due to spatially localized features that complicate characterizations limiting understanding of the physics of MTJs. Here, we combine advanced electron microscopy, spectroscopy, and first-principles calculations to obtain a direct structural and chemical imaging of the <span class="hlt">atomically</span> confined layers in a CoFeB-MgO MTJ, and clarify <span class="hlt">atom</span> diffusion and interface structures in the MTJ following annealing. The combined techniques demonstrate that B diffuses out of CoFeB electrodes into Ta interstitial sites rather than MgO after annealing, and CoFe bonds <span class="hlt">atomically</span> to MgO grains with an epitaxial orientation relationship by forming Fe(Co)-O bonds, yet without incorporation of CoFe in MgO. These findings afford a comprehensive perspective on structure and chemistry of MTJs, helping to develop high-performance spintronic devices by atomistic design. PMID:26905782</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21611729','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21611729"><span id="translatedtitle">Fe/Si(001) Ferromagnetic Layers: Reactivity, Local <span class="hlt">Atomic</span> Structure and <span class="hlt">Magnetism</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lungu, G. A.; Costescu, R. M.; Husanu, M. A.; Gheorghe, N. G.</p> <p>2011-10-03</p> <p>Ultrathin ferromagnetic Fe layers on Si(001) have recently been synthesized using the molecular beam epitaxy (MBE) technique, and their structural and <span class="hlt">magnetic</span> properties, as well as their interface reactivity have been investigated. The study was undertaken as function of the amount of Fe deposited and of substrate temperature. The interface reactivity was characterized by Auger electron spectroscopy (AES). The surface structure was characterized by low-energy electron diffraction (LEED). The <span class="hlt">magnetism</span> was investigated by magneto-optical Kerr effect (MOKE). A higher deposition temperature stabilizes a better surface ordering, but it also enhances Fe and Si interdiffusion and it therefore decreases the <span class="hlt">magnetism</span>. Despite the rapid disappearance of the long range order with Fe deposition at room temperature, the material exhibits a significant uniaxial in-plane <span class="hlt">magnetic</span> anisotropy. For the Fe deposition performed at high temperature (500 deg. C), a weak ferromagnetism is still observed, with saturation <span class="hlt">magnetization</span> of about 10% of the value obtained previously. MOKE studies allowed inferring the main properties of the distinct formed layers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4735899','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4735899"><span id="translatedtitle">Manipulating Majorana zero modes on <span class="hlt">atomic</span> rings with an external <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Li, Jian; Neupert, Titus; Bernevig, B. Andrei; Yazdani, Ali</p> <p>2016-01-01</p> <p>Non-Abelian quasiparticles have been predicted to exist in a variety of condensed matter systems. Their defining property is that an adiabatic braid between two of them results in a non-trivial change of the quantum state of the system. The simplest non-Abelian quasiparticles—the Majorana bound states—can occur in one-dimensional electronic nano-structures proximity-coupled to a bulk superconductor. Here we propose a set-up, based on chains of <span class="hlt">magnetic</span> adatoms on the surface of a thin-film superconductor, in which the control over an externally applied <span class="hlt">magnetic</span> field suffices to create and manipulate Majorana bound states. We consider specifically rings of adatoms and show that they allow for the creation, annihilation, adiabatic motion and braiding of pairs of Majorana bound states by varying the magnitude and orientation of the external <span class="hlt">magnetic</span> field. PMID:26791080</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AIPA....6b5005H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AIPA....6b5005H"><span id="translatedtitle"><span class="hlt">Atomic</span> scale understanding of <span class="hlt">magnetic</span> properties in Ni50Fe35Co15</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Herojit Singh, L.; Govindaraj, R.; Ravishankar, C.; Rajagopalan, S.; Amarendra, G.</p> <p>2016-02-01</p> <p>Mössbauer spectroscopic studies have been carried out at different temperatures across ferromagnetic to paramagnetic transition in Ni50Fe35Co15 and the evolution of hyperfine parameters such as centre shift and <span class="hlt">magnetic</span> hyperfine fields with temperature has been studied. Mössbauer spectrum obtained at 300 K in Ni50Fe35Co15 exhibiting fcc crystal structure is a six line pattern with the mean value of the hyperfine field close to 33 Tesla. Ferromagnetic to paramagnetic transition has been observed to occur in this system around 895 K matching with that of <span class="hlt">magnetization</span> results. Debye temperature of this nickel rich alloy is deduced to be around 470 K matching with that of Ni. Effect of prolonged annealing at 750 K on the <span class="hlt">magnetic</span> property is also investigated with respect to the thermal stability of the alloy .</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21582958','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21582958"><span id="translatedtitle">AN ESTIMATE OF THE NEARBY INTERSTELLAR <span class="hlt">MAGNETIC</span> FIELD USING NEUTRAL <span class="hlt">ATOMS</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Heerikhuisen, J.; Pogorelov, N. V.</p> <p>2011-09-01</p> <p>The strength and orientation of the <span class="hlt">magnetic</span> field in the nearby interstellar medium have remained elusive, despite continual improvements in observations and models. Data from NASA's Voyager mission and the Solar Wind ANisotropies (SWAN) experiment on board Solar and Heliospheric Observatory (SOHO) have placed observational constraints on the <span class="hlt">magnetic</span> field, and the more recent Interstellar Boundary Explorer (IBEX) data appear to also bear an imprint of the interstellar <span class="hlt">magnetic</span> field (ISMF). In this paper, we combine computational models of the heliosphere with data from Voyager, SOHO/SWAN, and IBEX to estimate both the strength and direction of the nearby ISMF. On the basis of our simulations, we find that a field strength of 2-3 {mu}G pointing from ecliptic coordinates (220-224, 39-44), combined with an interstellar hydrogen density of {approx}0.15 cm{sup -3}, produces results most consistent with observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26791080','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26791080"><span id="translatedtitle">Manipulating Majorana zero modes on <span class="hlt">atomic</span> rings with an external <span class="hlt">magnetic</span> field.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Li, Jian; Neupert, Titus; Bernevig, B Andrei; Yazdani, Ali</p> <p>2016-01-01</p> <p>Non-Abelian quasiparticles have been predicted to exist in a variety of condensed matter systems. Their defining property is that an adiabatic braid between two of them results in a non-trivial change of the quantum state of the system. The simplest non-Abelian quasiparticles-the Majorana bound states-can occur in one-dimensional electronic nano-structures proximity-coupled to a bulk superconductor. Here we propose a set-up, based on chains of <span class="hlt">magnetic</span> adatoms on the surface of a thin-film superconductor, in which the control over an externally applied <span class="hlt">magnetic</span> field suffices to create and manipulate Majorana bound states. We consider specifically rings of adatoms and show that they allow for the creation, annihilation, adiabatic motion and braiding of pairs of Majorana bound states by varying the magnitude and orientation of the external <span class="hlt">magnetic</span> field. PMID:26791080</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatCo...710395L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatCo...710395L"><span id="translatedtitle">Manipulating Majorana zero modes on <span class="hlt">atomic</span> rings with an external <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Jian; Neupert, Titus; Bernevig, B. Andrei; Yazdani, Ali</p> <p>2016-01-01</p> <p>Non-Abelian quasiparticles have been predicted to exist in a variety of condensed matter systems. Their defining property is that an adiabatic braid between two of them results in a non-trivial change of the quantum state of the system. The simplest non-Abelian quasiparticles--the Majorana bound states--can occur in one-dimensional electronic nano-structures proximity-coupled to a bulk superconductor. Here we propose a set-up, based on chains of <span class="hlt">magnetic</span> adatoms on the surface of a thin-film superconductor, in which the control over an externally applied <span class="hlt">magnetic</span> field suffices to create and manipulate Majorana bound states. We consider specifically rings of adatoms and show that they allow for the creation, annihilation, adiabatic motion and braiding of pairs of Majorana bound states by varying the magnitude and orientation of the external <span class="hlt">magnetic</span> field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhRvB..90n4434F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhRvB..90n4434F"><span id="translatedtitle">Defect propagation in one-, two-, and three-dimensional compounds doped by <span class="hlt">magnetic</span> <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Furrer, A.; Podlesnyak, A.; Krmer, K. W.; Strssle, Th.</p> <p>2014-10-01</p> <p>Inelastic neutron scattering experiments were performed to study manganese(II) dimer excitations in the diluted one-, two-, and three-dimensional compounds CsM nxM g1 -xB r3 , K2M nxZ n1 -xF4 , and KM nxZ n1 -xF3 (x ?0.10 ), respectively. The transitions from the ground-state singlet to the excited triplet, split into a doublet and a singlet due to the single-ion anisotropy, exhibit remarkable fine structures. These unusual features are attributed to local structural inhomogeneities induced by the dopant Mn <span class="hlt">atoms</span>, which act like lattice defects. Statistical models support the theoretically predicted decay of <span class="hlt">atomic</span> displacements according to 1 /r2 , 1 /r , and constant (for three-, two-, and one-dimensional compounds, respectively) where r denotes the distance of the displaced <span class="hlt">atoms</span> from the defect. The observed fine structures allow a direct determination of the local exchange interactions J , and the local intradimer distances R can be derived through the linear law d J /d R .</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1163590-defect-propagation-one-two-three-dimensional-compounds-doped-magnetic-atoms','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1163590-defect-propagation-one-two-three-dimensional-compounds-doped-magnetic-atoms"><span id="translatedtitle">Defect propagation in one-, two-, and three-dimensional compounds doped by <span class="hlt">magnetic</span> <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Furrer, A.; Podlesnyak, A.; Krämer, K. W.; Strässle, Th.</p> <p>2014-10-29</p> <p>Inelastic neutron scattering experiments were performed to study manganese(II) dimer excitations in the diluted one-, two-, and three-dimensional compounds CsMnxMg1-xBr3, K2MnxZn1-xF4, and KMnxZn1-xF3 (x≤0.10), respectively. The transitions from the ground-state singlet to the excited triplet, split into a doublet and a singlet due to the single-ion anisotropy, exhibit remarkable fine structures. These unusual features are attributed to local structural inhomogeneities induced by the dopant Mn <span class="hlt">atoms</span> which act like lattice defects. Statistical models support the theoretically predicted decay of <span class="hlt">atomic</span> displacements according to 1/r2, 1/r, and constant (for three-, two-, and one-dimensional compounds, respectively) where r denotes the distance ofmore » the displaced <span class="hlt">atoms</span> from the defect. In conclusion, the observed fine structures allow a direct determination of the local exchange interactions J, and the local intradimer distances R can be derived through the linear law dJ/dR.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26348798','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26348798"><span id="translatedtitle"><span class="hlt">Atomic</span>-Scale <span class="hlt">Magnetism</span> of Cr-Doped Bi2Se3 Thin Film Topological Insulators.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Wenqing; West, Damien; He, Liang; Xu, Yongbing; Liu, Jun; Wang, Kejie; Wang, Yong; van der Laan, Gerrit; Zhang, Rong; Zhang, Shengbai; Wang, Kang L</p> <p>2015-10-27</p> <p><span class="hlt">Magnetic</span> doping is the most common method for breaking time-reversal-symmetry surface states of topological insulators (TIs) to realize novel physical phenomena and to create beneficial technological applications. Here we present a study of the <span class="hlt">magnetic</span> coupling of a prototype <span class="hlt">magnetic</span> TI, that is, Cr-doped Bi2Se3, in its ultrathin limit which is expected to give rise to quantum anomalous Hall (QAH) effect. The high quality Bi2-xCrxSe3 epitaxial thin film was prepared using molecular beam epitaxy (MBE), characterized with scanning transimission electron microscopy (STEM), electrical magnetotransport, and X-ray <span class="hlt">magnetic</span> circularly dichroism (XMCD) techniques, and the results were simulated using density functional theory (DFT) with spin-orbit coupling (SOC). We observed a sizable spin moment mspin = (2.05 0.20) ?B/Cr and a small and negative orbital moment morb = (-0.05 0.02) ?B/Cr of the Bi1.94Cr0.06Se3 thin film at 2.5 K. A remarkable fraction of the (CrBi-CrI)(3+) antiferromagnetic dimer in the Bi2-xCrxSe3 for 0.02 < x < 0.40 was obtained using first-principles simulations, which was neglected in previous studies. The spontaneous coexistence of ferro- and antiferromagnetic Cr defects in Bi2-xCrxSe3 explains our experimental observations and those based on conventional magnetometry which universally report <span class="hlt">magnetic</span> moments significantly lower than 3 ?B/Cr predicted by Hund's rule. PMID:26348798</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21474405','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21474405"><span id="translatedtitle">SOLVING THE SCHROeDINGER AND DIRAC EQUATIONS FOR A HYDROGEN <span class="hlt">ATOM</span> IN THE UNIVERSE'S STRONGEST <span class="hlt">MAGNETIC</span> FIELDS WITH THE FREE COMPLEMENT METHOD</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Nakashima, Hiroyuki; Nakatsuji, Hiroshi</p> <p>2010-12-10</p> <p>The free complement method for solving the Schroedinger and Dirac equations has been applied to the hydrogen <span class="hlt">atom</span> in extremely strong <span class="hlt">magnetic</span> fields. For very strong fields such as those observed on the surfaces of white dwarf and neutron stars, we calculate the highly accurate non-relativistic and relativistic energies of the hydrogen <span class="hlt">atom</span>. We extended the calculations up to field strengths that exceed the strongest <span class="hlt">magnetic</span> field ({approx}10{sup 15} G) ever observed in the universe on a magnetar surface. These are the first reported accurate quantum mechanical calculations ever to include such strong fields. Certain excited state bands in extremely strong fields showed perfect diamagnetism with an infinite number of degenerate states with the same energies as for a hydrogen <span class="hlt">atom</span> in the absence of a field. Our method of solving the Schroedinger and Dirac equations provides an accurate theoretical methodology for studying phenomena that occur under strong <span class="hlt">magnetic</span> fields.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26923173','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26923173"><span id="translatedtitle"><span class="hlt">Magnetic</span> Properties of a Single-Molecule Lanthanide-Transition-Metal Compound Containing 52 Gadolinium and 56 Nickel <span class="hlt">Atoms</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Da-Peng; Lin, Xin-Ping; Zhang, Hui; Zheng, Xiu-Ying; Zhuang, Gui-Lin; Kong, Xiang-Jian; Long, La-Sheng; Zheng, Lan-Sun</p> <p>2016-03-24</p> <p>Monodisperse metal clusters provide a unique platform for investigating <span class="hlt">magnetic</span> exchange within molecular <span class="hlt">magnets</span>. Herein, the core-shell structure of the monodisperse molecule <span class="hlt">magnet</span> of [Gd52 Ni56 (IDA)48 (OH)154 (H2 O)38 ]@SiO2 (1 a@SiO2 ) was prepared by encapsulating one high-nuclearity lanthanide-transition-metal compound of [Gd52 Ni56 (IDA)48 (OH)154 (H2 O)38 ]⋅(NO3 )18 ⋅164 H2 O (1) (IDA=iminodiacetate) into one silica nanosphere through a facile one-pot microemulsion method. 1 a@SiO2 was characterized using transmission electron microscopy, N2 adsorption-desorption isotherms, and inductively coupled plasma-<span class="hlt">atomic</span> emission spectrometry. <span class="hlt">Magnetic</span> investigation of 1 and 1 a revealed J1 =0.25 cm(-1) , J2 =-0.060 cm(-1) , J3 =-0.22 cm(-1) , J4 =-8.63 cm(-1) , g=1.95, and z J=-2.0×10(-3)  cm(-1) for 1, and J1 =0.26 cm(-1) , J2 =-0.065 cm(-1) , J3 =-0.23 cm(-1) , J4 =-8.40 cm(-1)  g=1.99, and z J=0.000 cm(-1) for 1 a@SiO2 . The z J=0 in 1 a@SiO2 suggests that weak antiferromagnetic coupling between the compounds is shielded by silica nanospheres. PMID:26923173</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JETPL.101..258V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JETPL.101..258V"><span id="translatedtitle">In situ study of <span class="hlt">atomic</span>-vacancy ordering in stoichiometric titanium monoxide by the <span class="hlt">magnetic</span> susceptibility</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Valeeva, A. A.; Nazarova, S. Z.; Rempel, A. A.</p> <p>2015-02-01</p> <p>An in situ temperature study of a variation in the degree of long-range order in stoichiometric titanium monoxide has been performed by the <span class="hlt">magnetic</span> susceptibility method. The measurements have been performed on annealed and quenched titanium monoxide in the temperature range from 300 to 1200 K. It has been found that the degree of long-range order depends on the regime and temperature of annealing of the initial samples. The degree of long-range order in the process of measurement of the <span class="hlt">magnetic</span> susceptibility varies from 0.21 to 1.00; the larger the degree of long-range order, the smaller the <span class="hlt">magnetic</span> susceptibility. Furthermore, the long-range order parameter decreases with an increase in the temperature above 1200 K and vanishes sharply at the order-disorder transition temperature. According to the results of this work, the critical long-range order parameter is 0.21 and the temperature of the nonequilibrium disorder-order transition is about 1073 K.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JAP...117qB733C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JAP...117qB733C"><span id="translatedtitle">Interaction transfer of silicon <span class="hlt">atoms</span> forming Co silicide for Co/ ?{ 3 } ?{ 3 } R 30 -Ag/Si(111) and related <span class="hlt">magnetic</span> properties</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chang, Cheng-Hsun-Tony; Fu, Tsu-Yi; Tsay, Jyh-Shen</p> <p>2015-05-01</p> <p>Combined scanning tunneling microscopy, Auger electron spectroscopy, and surface magneto-optic Kerr effect studies were employed to study the microscopic structures and <span class="hlt">magnetic</span> properties for ultrathin Co/ ?{ 3 } ?{ 3 } R 30 -Ag/Si(111). As the annealing temperature increases, the upward diffusion of Si <span class="hlt">atoms</span> and formation of Co silicides occurs at temperature above 400 K. Below 600 K, the ?{ 3 } ?{ 3 } R 30 -Ag/Si(111) surface structure persists. We propose an interaction transferring mechanism of Si <span class="hlt">atoms</span> across the ?{ 3 } ?{ 3 } R 30 -Ag layer. The upward transferred Si <span class="hlt">atoms</span> react with Co <span class="hlt">atoms</span> to form Co silicide. The step height across the edge of the island, a separation of 0.75 nm from the analysis of the 2 2 structure, and the calculations of the normalized Auger signal serve as strong evidences for the formation of CoSi2 at the interface. The interaction transferring mechanism for Si <span class="hlt">atoms</span> enhances the possibility of interactions between Co and Si <span class="hlt">atoms</span>. The smoothness of the surface is advantage for that the easy axis of <span class="hlt">magnetization</span> for Co/ ?{ 3 } ?{ 3 } R 30 -Ag/Si(111) is in the surface plane. This provides a possible way of growing flat <span class="hlt">magnetic</span> layers on silicon substrate with controllable silicide formation and shows potential applications in spintronics devices.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22409981','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22409981"><span id="translatedtitle">Interaction transfer of silicon <span class="hlt">atoms</span> forming Co silicide for Co/√(3)×√(3)R30°-Ag/Si(111) and related <span class="hlt">magnetic</span> properties</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chang, Cheng-Hsun-Tony; Fu, Tsu-Yi; Tsay, Jyh-Shen</p> <p>2015-05-07</p> <p>Combined scanning tunneling microscopy, Auger electron spectroscopy, and surface magneto-optic Kerr effect studies were employed to study the microscopic structures and <span class="hlt">magnetic</span> properties for ultrathin Co/√(3)×√(3)R30°-Ag/Si(111). As the annealing temperature increases, the upward diffusion of Si <span class="hlt">atoms</span> and formation of Co silicides occurs at temperature above 400 K. Below 600 K, the √(3)×√(3)R30°-Ag/Si(111) surface structure persists. We propose an interaction transferring mechanism of Si <span class="hlt">atoms</span> across the √(3)×√(3)R30°-Ag layer. The upward transferred Si <span class="hlt">atoms</span> react with Co <span class="hlt">atoms</span> to form Co silicide. The step height across the edge of the island, a separation of 0.75 nm from the analysis of the 2 × 2 structure, and the calculations of the normalized Auger signal serve as strong evidences for the formation of CoSi{sub 2} at the interface. The interaction transferring mechanism for Si <span class="hlt">atoms</span> enhances the possibility of interactions between Co and Si <span class="hlt">atoms</span>. The smoothness of the surface is advantage for that the easy axis of <span class="hlt">magnetization</span> for Co/√(3)×√(3)R30°-Ag/Si(111) is in the surface plane. This provides a possible way of growing flat <span class="hlt">magnetic</span> layers on silicon substrate with controllable silicide formation and shows potential applications in spintronics devices.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22306329','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22306329"><span id="translatedtitle">Two Keggin-type heteropolytungstates with transition metal as a central <span class="hlt">atom</span>: Crystal structure and <span class="hlt">magnetic</span> study with 2D-IR correlation spectroscopy</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chai, Feng; Chen, YiPing; You, ZhuChai; Xia, ZeMin; Ge, SuZhi; Sun, YanQiong; Huang, BiHua</p> <p>2013-06-01</p> <p>Two Keggin-type heteropolytungstates, [Co(phen)?]?[CoW??O??]9H?O 1 (phen=1,10-phenanthroline) and [Fe(phen)?]?[FeW??O??]H?OH?O 2, have been synthesized via the hydrothermal technique and characterized by single crystal X-ray diffraction analyses, IR, XPS, TG analysis, UVDRS, XRD, thermal-dependent and <span class="hlt">magnetic</span>-dependent 2D-COS IR (two-dimensional infrared correlation spectroscopy). Crystal structure analysis reveals that the polyanions in compound 1 are linked into 3D supramolecule through hydrogen bonding interactions between lattice water molecules and terminal oxygen <span class="hlt">atoms</span> of polyanion units, and [Co(phen)?]? cations distributed in the polyanion framework with many hydrogen bonding interactions. The XPS spectra indicate that all the Co <span class="hlt">atoms</span> in 1 are +2 oxidation state, the Fe <span class="hlt">atoms</span> in 2 existing with +2 and +3 mixed oxidation states. - Graphical abstract: The <span class="hlt">magnetic</span>-dependent synchronous 2D correlation IR spectra of 1 (a), 2 (b) over 050 mT in the range of 6001000 cm?, the obvious response indicate two Keggin polyanions skeleton susceptible to applied <span class="hlt">magnetic</span> field. Highlights: Two Keggin-type heteropolytungstates with transition metal as a central <span class="hlt">atom</span> has been obtained. Compound 1 forms into 3D supramolecular architecture through hydrogen bonding between water molecules and polyanions. <span class="hlt">Magnetic</span>-dependent 2D-IR correlation spectroscopy was introduced to discuss the <span class="hlt">magnetism</span> of polyoxometalate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JAP...112k4324H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JAP...112k4324H"><span id="translatedtitle">Enhanced quality factors and force sensitivity by attaching <span class="hlt">magnetic</span> beads to cantilevers for <span class="hlt">atomic</span> force microscopy in liquid</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hoof, Sebastian; Nand Gosvami, Nitya; Hoogenboom, Bart W.</p> <p>2012-12-01</p> <p>Dynamic-mode <span class="hlt">atomic</span> force microscopy (AFM) in liquid remains complicated due to the strong viscous damping of the cantilever resonance. Here, we show that a high-quality resonance (Q >20) can be achieved in aqueous solution by attaching a microgram-bead at the end of the nanogram-cantilever. The resulting increase in cantilever mass causes the resonance frequency to drop significantly. However, the force sensitivityas expressed via the minimum detectable force gradientis hardly affected, because of the enhanced quality factor. Through the enhancement of the quality factor, the attached bead also reduces the relative importance of noise in the deflection detector. It can thus yield an improved signal-to-noise ratio when this detector noise is significant. We describe and analyze these effects for a set-up that includes <span class="hlt">magnetic</span> actuation of the cantilevers and that can be easily implemented in any AFM system that is compatible with an inverted optical microscope.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009JPhA...42e5209E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009JPhA...42e5209E"><span id="translatedtitle">Complete classification of qualitatively different perturbations of the hydrogen <span class="hlt">atom</span> in weak near-orthogonal electric and <span class="hlt">magnetic</span> fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Efstathiou, K.; Lukina, O. V.; Sadovski, D. A.</p> <p>2009-02-01</p> <p>We consider perturbations of the hydrogen <span class="hlt">atom</span> by sufficiently small homogeneous static electric and <span class="hlt">magnetic</span> fields in near-orthogonal configurations. Normalization of the Keplerian symmetry reveals that in the parameter space such systems belong in a 'zone' of systems close to the 1:1 resonance, the latter corresponding to the exactly orthogonal configuration. Integrable approximations obtained from second normalization of systems in the 1:1 zone are classified into several different qualitative types, many of which possess nontrivial monodromy. We compute monodromy of the complete three-dimensional energy-momentum map, compare the joint quantum spectrum to classical bifurcation diagrams, and show the effect of second normalization to the joint spectrum.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AcSpe.107..115Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AcSpe.107..115Z"><span id="translatedtitle">Novel ion imprinted <span class="hlt">magnetic</span> mesoporous silica for selective <span class="hlt">magnetic</span> solid phase extraction of trace Cd followed by graphite furnace <span class="hlt">atomic</span> absorption spectrometry detection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, Bingshan; He, Man; Chen, Beibei; Hu, Bin</p> <p>2015-05-01</p> <p>Determination of trace Cd in environmental, biological and food samples is of great significance to toxicological research and environmental pollution monitoring. While the direct determination of Cd in real-world samples is difficult due to its low concentration and the complex matrix. Herein, a novel Cd(II)-ion imprinted <span class="hlt">magnetic</span> mesoporous silica (Cd(II)-II-MMS) was prepared and was employed as a selective <span class="hlt">magnetic</span> solid-phase extraction (MSPE) material for extraction of trace Cd in real-world samples followed by graphite furnace <span class="hlt">atomic</span> absorption spectrometry (GFAAS) detection. Under the optimized conditions, the detection limit of the proposed method was 6.1 ng L- 1 for Cd with the relative standard deviation (RSD) of 4.0% (c = 50 ng L- 1, n = 7), and the enrichment factor was 50-fold. To validate the proposed method, Certified Reference Materials of GSBZ 50009-88 environmental water, ZK018-1 lyophilized human urine and NIES10-b rice flour were analyzed and the determined values were in a good agreement with the certified values. The proposed method exhibited a robust anti-interference ability due to the good selectivity of Cd(II)-II-MMS toward Cd(II). It was successfully employed for the determination of trace Cd(II) in environmental water, human urine and rice samples with recoveries of 89.3-116%, demonstrating that the proposed method has good application potential in real world samples with complex matrix.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AIPC.1665m0048B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AIPC.1665m0048B"><span id="translatedtitle">Fe2-xCoxMnSi (x = 0, 1 and 2) Heusler alloys: Structural, <span class="hlt">magnetic</span> and <span class="hlt">atomic</span> site disorder properties</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bhatt, Harsh; Mukadam, M. D.; Meena, S. S.; Yusuf, S. M.</p> <p>2015-06-01</p> <p>The Heusler alloy series Fe2-xCoxMnSi (x = 0, 1 and 2) is theoretically predicted to be half metallic. We prepared the sample series and determined the structural and <span class="hlt">magnetic</span> properties to check if these materials are suitable for spintronics applications. The Curie temperatures of two of the alloys have been found to be well above the room temperature. But the presence of elements with <span class="hlt">atoms</span> of similar size leads to <span class="hlt">atomic</span> site disorder in these alloys, which may destroy the half metallic nature. The <span class="hlt">atomic</span> site disorder has been confirmed by Mssbauer spectroscopy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhRvA..89e2522T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhRvA..89e2522T"><span id="translatedtitle">Two-dimensional pseudospectral Hartree-Fock method for low-Z <span class="hlt">atoms</span> in intense <span class="hlt">magnetic</span> fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thirumalai, Anand; Heyl, Jeremy S.</p> <p>2014-05-01</p> <p>The energy levels of the first few low-lying states of helium and lithium <span class="hlt">atoms</span> in intense <span class="hlt">magnetic</span> fields up to ?108-109 T are calculated in this study. A pseudospectral method is employed for the computational procedure. The methodology involves computing the eigenvalues and eigenvectors of the generalized two-dimensional Hartree-Fock partial differential equations for these two- and three-electron systems in a self-consistent manner. The method exploits the natural symmetries of the problem without assumptions of any basis functions for expressing the wave functions of the electrons or the commonly employed adiabatic approximation. It is found that the results obtained here for a few of the most tightly bound states of each of the <span class="hlt">atoms</span>, helium and lithium, are in good agreement with findings elsewhere. In this regard, we report data for two states of lithium that were lacking thus far. It is also seen that the pseudospectral method employed here is considerably more economical, from a computational point of view, than previously employed methods such as a finite-element-based approach. The key enabling advantage of the method described here is the short computational times, which are on the order of seconds for obtaining accurate results for heliumlike systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24988469','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24988469"><span id="translatedtitle">Sub-nanometer <span class="hlt">atomic</span> layer deposition for spintronics in <span class="hlt">magnetic</span> tunnel junctions based on graphene spin-filtering membranes.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Martin, Marie-Blandine; Dlubak, Bruno; Weatherup, Robert S; Yang, Heejun; Deranlot, Cyrile; Bouzehouane, Karim; Petroff, Frédéric; Anane, Abdelmadjid; Hofmann, Stephan; Robertson, John; Fert, Albert; Seneor, Pierre</p> <p>2014-08-26</p> <p>We report on the successful integration of low-cost, conformal, and versatile <span class="hlt">atomic</span> layer deposited (ALD) dielectric in Ni–Al2O3–Co <span class="hlt">magnetic</span> tunnel junctions (MTJs) where the Ni is coated with a spin-filtering graphene membrane. The ALD tunnel barriers, as thin as 0.6 nm, are grown layer-by-layer in a simple, low-vacuum, ozone-based process, which yields high-quality electron-transport barriers as revealed by tunneling characterization. Even under these relaxed conditions, including air exposure of the interfaces, a significant tunnel magnetoresistance is measured highlighting the robustness of the process. The spin-filtering effect of graphene is enhanced, leading to an almost fully inversed spin polarization for the Ni electrode of −42%. This unlocks the potential of ALD for spintronics with conformal, layer-by-layer control of tunnel barriers in <span class="hlt">magnetic</span> tunnel junctions toward low-cost fabrication and down-scaling of tunnel resistances. PMID:24988469</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010PhRvB..81n4431X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010PhRvB..81n4431X"><span id="translatedtitle">Liquids in multiorbital SU(N) <span class="hlt">magnets</span> made up of ultracold alkaline-earth <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, Cenke</p> <p>2010-04-01</p> <p>In this work we study one family of liquid states of k -orbital SU(N) spin systems, focusing on the case of k=2 which can be realized by ultracold alkaline-earth <span class="hlt">atoms</span> trapped in optical lattices, with N as large as 10. Five different algebraic liquid states with selectively coupled charge, spin, and orbital quantum fluctuations are considered. The algebraic liquid states can be stabilized with large enough N and the scaling dimension of physical order parameters is calculated using a systematic 1/N expansion. The phase transitions between these liquid states are also studied and all the algebraic liquid states discussed in this work can be obtained from one “mother” state with SU(2)×U(1) gauge symmetry.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPhD...48u5306X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPhD...48u5306X"><span id="translatedtitle">Adsorption of Ti <span class="hlt">atoms</span> on zigzag silicene nanoribbons: influence on electric, <span class="hlt">magnetic</span>, and thermoelectric properties</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, Long; Wang, Xue-Feng; Zhou, Liping; Yang, Zhi-Yong</p> <p>2015-06-01</p> <p>We study the adsorption effects of Ti <span class="hlt">atoms</span> on the physical properties of zigzag silicene nanoribbons using the density functional theory combined with the nonequilibrium Greens function methods. The adsorption geometries, conductance spectra, current voltage curves, spin polarizations, magnetoresistance, and Seebeck coefficients are evaluated in different adsorption samples. Ti adatoms prefer sites inside the nanoribbons instead of on the edges. Two neighboring adatoms are attractively coupled and prefer being adsorbed on the same side. The giant magnetoresistance in nanoribbons of even width is usually greatly reduced, except in symmetric adsorption cases. Strong spin negative differential resistance phenomena can be observed and pure spin current can be produced by temperature gradient in specific cases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016CPL...646..148C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016CPL...646..148C"><span id="translatedtitle">The <span class="hlt">magnetic</span> and transport properties of edge passivated silicene nanoribbon by Mn <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Changpeng; Zhu, Ziqing; Zha, Dace; Qi, Meilan; Wu, Jinping</p> <p>2016-02-01</p> <p>The effect of chemical doping on the ZSiNRs with Mn as passivating element replacing H <span class="hlt">atoms</span> at one edge are investigated by first-principles calculations. The structures optimized in the typical ferromagnetic and antiferromagnetic coupling show that the system leads to an AFM state and achieve half-metallic properties. Also, our first principle approach based on the Keldysh non-equilibrium Green's function method gives the spin-dependent transport properties of the device. When the system changes from parallel to antiparallel configuration. The spin-up current increases rapidly while the spin-up current is still depressed. Further, it is found that the system is a quite good spin filtering device with nearly 80% spin filtering efficiency at a wide bias voltage region and therefore suitable for applications. The mechanisms for these phenomena are proposed in detail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24993103','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24993103"><span id="translatedtitle"><span class="hlt">Magnetic</span> field and temperature sensing with <span class="hlt">atomic</span>-scale spin defects in silicon carbide.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kraus, H; Soltamov, V A; Fuchs, F; Simin, D; Sperlich, A; Baranov, P G; Astakhov, G V; Dyakonov, V</p> <p>2014-01-01</p> <p>Quantum systems can provide outstanding performance in various sensing applications, ranging from bioscience to nanotechnology. <span class="hlt">Atomic</span>-scale defects in silicon carbide are very attractive in this respect because of the technological advantages of this material and favorable optical and radio frequency spectral ranges to control these defects. We identified several, separately addressable spin-3/2 centers in the same silicon carbide crystal, which are immune to nonaxial strain fluctuations. Some of them are characterized by nearly temperature independent axial crystal fields, making these centers very attractive for vector magnetometry. Contrarily, the zero-field splitting of another center exhibits a giant thermal shift of -1.1?MHz/K at room temperature, which can be used for thermometry applications. We also discuss a synchronized composite clock exploiting spin centers with different thermal response. PMID:24993103</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4081891','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4081891"><span id="translatedtitle"><span class="hlt">Magnetic</span> field and temperature sensing with <span class="hlt">atomic</span>-scale spin defects in silicon carbide</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kraus, H.; Soltamov, V. A.; Fuchs, F.; Simin, D.; Sperlich, A.; Baranov, P. G.; Astakhov, G. V.; Dyakonov, V.</p> <p>2014-01-01</p> <p>Quantum systems can provide outstanding performance in various sensing applications, ranging from bioscience to nanotechnology. <span class="hlt">Atomic</span>-scale defects in silicon carbide are very attractive in this respect because of the technological advantages of this material and favorable optical and radio frequency spectral ranges to control these defects. We identified several, separately addressable spin-3/2 centers in the same silicon carbide crystal, which are immune to nonaxial strain fluctuations. Some of them are characterized by nearly temperature independent axial crystal fields, making these centers very attractive for vector magnetometry. Contrarily, the zero-field splitting of another center exhibits a giant thermal shift of ?1.1?MHz/K at room temperature, which can be used for thermometry applications. We also discuss a synchronized composite clock exploiting spin centers with different thermal response. PMID:24993103</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApJ...814..112F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApJ...814..112F"><span id="translatedtitle">Charting the Interstellar <span class="hlt">Magnetic</span> Field causing the Interstellar Boundary Explorer (IBEX) Ribbon of Energetic Neutral <span class="hlt">Atoms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Frisch, P. C.; Berdyugin, A.; Piirola, V.; Magalhaes, A. M.; Seriacopi, D. B.; Wiktorowicz, S. J.; Andersson, B.-G.; Funsten, H. O.; McComas, D. J.; Schwadron, N. A.; Slavin, J. D.; Hanson, A. J.; Fu, C.-W.</p> <p>2015-12-01</p> <p>The interstellar <span class="hlt">magnetic</span> field (ISMF) near the heliosphere is a fundamental component of the solar galactic environment that can only be studied using polarized starlight. The results of an ongoing survey of the linear polarizations of local stars are analyzed with the goal of linking the ISMF that shapes the heliosphere to the nearby field in interstellar space. We present new results on the direction of the <span class="hlt">magnetic</span> field within 40 pc obtained from analyzing polarization data using a merit function that determines the field direction that provides the best fit to the polarization data. Multiple <span class="hlt">magnetic</span> components are identified, including a dominant interstellar field, {B}{POL}, that is aligned with the direction ?, b = 36.2, 49.0 (16.0). Stars tracing {B}{POL} have the same mean distance as stars that do not trace {B}{POL}, but show weaker average polarizations consistent with a smaller column density of polarizing material. {B}{POL} is aligned with the ISMF traced by the IBEX Ribbon to within {7.6}-7.6+14.9 degrees. The variations in the polarization position angle directions derived from the data that best match {B}{POL} indicate a low level of <span class="hlt">magnetic</span> turbulence, 9 1. The direction of {B}{POL} is obtained after excluding polarization data tracing a separate <span class="hlt">magnetic</span> structure that appears to be associated with interstellar dust deflected around the heliosphere. The velocities of local interstellar clouds relative to the Local Standard of Rest (LSR) increase with the angles between the LSR velocities and {B}{POL}, indicating that the kinematics of local interstellar material is ordered by the ISMF. The Loop I superbubble that extends close to the Sun contains dust that reddens starlight and whose distance is determined by the color excess E(B - V) of starlight. Polarizations caused by grains aligned with respect to {B}{POL} are consistent with the location of the Sun in the rim of the Loop I superbubble. An angle of {76.8}-27.6+23.5 between {B}{POL} and the bulk LSR velocity the local interstellar material indicates a geometry that is consistent with an expanding superbubble. The efficiency of grain alignment in the local interstellar medium has been assessed using stars where both polarization data and hydrogen column density data are available. Nearby stars appear to have larger polarizations than expected based on reddened sightlines, which is consistent with previous results, but uncertainties are large. Optical polarization and color excess E(B - V) data indicate the presence of nearby interstellar dust in the BICEP2 field. Color excess E(B - V) indicates an optical extinction of AV > 0.6 in the BICEP2 field, while the polarization data indicate that AV > 0.09 mag. The IBEX Ribbon ISMF extends to the boundaries of the BICEP2 region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20640184','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20640184"><span id="translatedtitle"><span class="hlt">Magnetic</span> circular dichroism in the ion yield of polarized chromium <span class="hlt">atoms</span> at the 2p edge</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Pruemper, G.; Viefhaus, J.; Becker, U.; Kroeger, S.; Mueller, R.; Zimmermann, P.; Martins, M.</p> <p>2003-09-01</p> <p>The effect of <span class="hlt">magnetic</span> dichroism in the partial and total ion yield of chromium, i.e., the absorption of polarized chromium vapor was observed in the gas phase. The measurements were performed at the 2p edge and at photon energies above the 2p edge. The structure of the dichroism at the 2p edge can be understood by including the coupling of the 2p hole with the 3d and 4s shells. Our experimental results for the dichroism at the 2p edge are similar to results of solid-state experiments. Implications for the sum rules used as a standard tool to calculate the spin and orbital momentum are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21231068','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21231068"><span id="translatedtitle">"Artificial <span class="hlt">atoms</span>" in <span class="hlt">magnetic</span> fields: wave-function shaping and phase-sensitive tunneling.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lei, Wen; Notthoff, Christian; Peng, Jie; Reuter, Dirk; Wieck, Andreas; Bester, Gabriel; Lorke, Axel</p> <p>2010-10-22</p> <p>We demonstrate the possibility to influence the shape of the wave functions in semiconductor quantum dots by the application of an external <span class="hlt">magnetic</span> field B(z). The states of the so-called p shell, which show distinct orientations along the crystal axes for B(z) = 0, can be modified to become more and more circularly symmetric with an increasing field. Their changing probability density can be monitored using magnetotunneling wave function mapping. Calculations of the magnetotunneling signals are in good agreement with the experimental data and explain the different tunneling maps of the p(+) and p? states as a consequence of the different sign of their respective phase factors. PMID:21231068</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1236758-scanning-tunneling-spectroscopy-magnetic-atom-graphene-kondo-regime','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1236758-scanning-tunneling-spectroscopy-magnetic-atom-graphene-kondo-regime"><span id="translatedtitle">Scanning tunneling spectroscopy of a <span class="hlt">magnetic</span> <span class="hlt">atom</span> on graphene in the Kondo regime</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Zhuang, Huai -Bin; Sun, Qing -feng; Xie, X. C.</p> <p>2009-06-23</p> <p>In this study, the Kondo effect in the system consisting of a <span class="hlt">magnetic</span> adatom on the graphene is studied. By using the non-equilibrium Green function method with the slave-boson mean field approximation, the local density of state (LDOS) and the conductance are calculated. For a doped graphene, the Kondo phase is present at all time. Surprisingly, two kinds of Kondo regimes are revealed. But for the undoped graphene, the Kondo phase only exists if the adatoms energy level is beyond a critical value. The conductance is similar to the LDOS, thus, the Kondo peak in the LDOS can be observedmorewith the scanning tunneling spectroscopy. In addition, in the presence of a direct coupling between the STM tip and the graphene, the conductance may be dramatically enhanced, depending on the coupling site.less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1236758','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1236758"><span id="translatedtitle">Scanning tunneling spectroscopy of a <span class="hlt">magnetic</span> <span class="hlt">atom</span> on graphene in the Kondo regime</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zhuang, Huai -Bin; Sun, Qing -feng; Xie, X. C.</p> <p>2009-06-23</p> <p>In this study, the Kondo effect in the system consisting of a <span class="hlt">magnetic</span> adatom on the graphene is studied. By using the non-equilibrium Green function method with the slave-boson mean field approximation, the local density of state (LDOS) and the conductance are calculated. For a doped graphene, the Kondo phase is present at all time. Surprisingly, two kinds of Kondo regimes are revealed. But for the undoped graphene, the Kondo phase only exists if the adatoms energy level is beyond a critical value. The conductance is similar to the LDOS, thus, the Kondo peak in the LDOS can be observed with the scanning tunneling spectroscopy. In addition, in the presence of a direct coupling between the STM tip and the graphene, the conductance may be dramatically enhanced, depending on the coupling site.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22054261','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22054261"><span id="translatedtitle">Structure and <span class="hlt">magnetic</span> properties of heterometallic coordination carboxylate polymers with cobalt and lithium <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Evstifeev, I. E.; Kiskin, M. A.; Bogomyakov, A. S.; Sidorov, A. A.; Novotortsev, V. M.; Eremenko, I. L.</p> <p>2011-09-15</p> <p>Reactions between lithium pivalate and cobalt coordination polymers [Co{sub 5}(OH{sub 2})(OH)(Piv){sub 9})L{sup 1}){sub 4}]{sub n} (I) and [Co{sub 2}(OH{sub 2})(Piv){sub 4}(L{sup 2}){sub 2}]{sub n} (II), where Piv-is the pivalate anion, L{sup 1} is pyrazine, and L{sup 2} is pyrimidine, result in new heterometallic polymers {l_brace}[Li{sub 2}Co{sub 2}(Piv){sub 6}(L{sup 1}){sub 2}]{sub 2}MeCN{r_brace}{sub n} (III), {l_brace}[Li{sub 2}Co{sub 2}(Piv){sub 6}(L{sup 2})]{sub 0.5}MeCN{r_brace}{sub n} (IV), and [Li{sub 2}Co{sub 2}(Piv){sub 6}(L{sup 2}){sub 2}]{sub n} (V). The resulting compounds contain tetra-nuclear {l_brace}Li{sub 2}Co{sub 2}(Piv){sub 6}{r_brace} fragments connected by neutral bridging ligands (pyrazine or pyrimidine) into layer structures. Crystal structures III-V are determined, and the <span class="hlt">magnetic</span> properties of III and IV are studied.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950045398&hterms=models+atoms&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dmodels%2Batoms','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950045398&hterms=models+atoms&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dmodels%2Batoms"><span id="translatedtitle">Middle- and low-latitude emissions from energetic neutral <span class="hlt">atom</span> precipitation seen from ATLAS 1 under quiet <span class="hlt">magnetic</span> conditions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tinsley, B. A.; Rohrbaugh, R. P.; Ishimoto, M.; Torr, M. R.; Torr, D. G.</p> <p>1994-01-01</p> <p>During the ATLAS 1 mission spectral observations were made at middle and low latitudes of features expected from the precipitation of energetic neutral <span class="hlt">atoms</span>. The Imaging Spectrometric Observatory was used at night in the UV and visible with maximum gain. The tangent ray heights of the look directions ranged from near 100 km to near 200 km, and the geomagnetic conditions were quiet during the observations, which were made March 28 to April 3, 1992. The N2(+) 1N 391.4-nm and O I 130.4 and 135.6-nm emissions were observed at all latitudes, with lower emission rates at lower <span class="hlt">magnetic</span> dip latitudes, except that enhancements in the O I lines were seen within 30 deg of the dip equator to radiative recombination of ionospheric plasma. The latitude profile observed for the N2(+) 1N emission did not show an equatorial or midlatitude peak. This implies that the source of energetic neutrals is more consistent with prompt charge exchange loss of freshly injected trapped ions with relatively low mirror heights (i.e., ions on higher L shells with equatorial pitch angle distributions nearly isotropic to the loss cone) than loss of highly eroded populations of particles with high mirror heights (i.e., ions on lower L shells with pancake equatorial pitch angle distributions). The N2(+) 1N emission rates have been compared with models of atmospheric emission due to fluxes of O/O(+) and H/H(+) in the thermosphere, as produced by energetic neutral oxygen or hydrogen <span class="hlt">atom</span> precipitation. Energy deposition rates are inferred.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JMMM..343....1K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JMMM..343....1K"><span id="translatedtitle">Fabrication and <span class="hlt">magnetic</span> properties of FePt/Al2O3 composite film by <span class="hlt">atomic</span>-layer-deposition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kong, Ji-Zhou; Gao, Mo-Yun; Zhai, Hai-Fa; Yan, Qing-Yu; Li, Ai-Dong; Li, Hui; Wu, Di</p> <p>2013-10-01</p> <p>Self-assembled face-centered cubic FePt nanoparticles were capped by a amorphous Al2O3 capping layer with the thickness of 10 nm using the <span class="hlt">atomic</span> layer deposition (ALD) technology, and transmission electron microscopy indicates that the FePt nanocrystals are well-separated. After annealing the composite film at 700 C, well-monodispersed face-centered tetragonal FePt particles can be obtained, yielding a coercivity value Hc=5.9 kOe with the magnetocrystalline anisotropy of 3.86 MJ/m3. The thermal factor for the composite film is 68.5, meeting the industry requirement (KuV/kBT ? 50). The protection of amorphous Al2O3 matrix can effectively inhibit grain growth and particle aggregation, and preserve the ordered domains of FePt nanoparticles during the L10 ordering transition. The combination of ALD-capping layer and self-assembled FePt nanoparticles provides a new potential approach to fabricate patterned <span class="hlt">magnetic</span> recording media with ultrahigh areal density.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..MARF21013K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..MARF21013K"><span id="translatedtitle">Radiation pressure excitation of Low Temperature <span class="hlt">Atomic</span> Force & <span class="hlt">Magnetic</span> Force Microscope (LT-AFM/MFM) for Imaging</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karci, Ozgur; Celik, Umit; Oral, Ahmet; NanoMagnetics Instruments Ltd. Team; Middle East Tech Univ Team</p> <p>2015-03-01</p> <p>We describe a novel method for excitation of <span class="hlt">Atomic</span> Force Microscope (AFM) cantilevers by means of radiation pressure for imaging in an AFM for the first time. Piezo excitation is the most common method for cantilever excitation, but it may cause spurious resonance peaks. A fiber optic interferometer with 1310 nm laser was used both to measure the deflection of cantilever and apply a force to the cantilever in a LT-AFM/MFM from Nano<span class="hlt">Magnetics</span> Instruments. The laser power was modulated at the cantilevers resonance frequency by a digital Phase Lock Loop (PLL). The force exerted by the radiation pressure on a perfectly reflecting surface by a laser beam of power P is F = 2P/c. We typically modulate the laser beam by ~ 800 μW and obtain 10nm oscillation amplitude with Q ~ 8,000 at 2.5x10-4 mbar. The cantilever's stiffness can be accurately calibrated by using the radiation pressure. We have demonstrated performance of the radiation pressure excitation in AFM/MFM by imaging a hard disk sample between 4-300K and Abrikosov vortex lattice in BSCCO single crystal at 4K to for the first time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JMMM..401..816M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JMMM..401..816M"><span id="translatedtitle">The elastic, electronic and <span class="hlt">magnetism</span> structure of the MAl and M3Al (M=Fe and Ni) alloy with and without hydrogen <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mubarak, A. A.</p> <p>2016-03-01</p> <p>The energetic stability, electronic and <span class="hlt">magnetism</span> of the MAl, M3Al alloy (M=Fe, Ni) and variant surfaces of MAl (001) with and without hydrogen <span class="hlt">atoms</span> are investigated by utilizing DFT and GGA as the exchange-correlation potential. All presented alloys with and without the H <span class="hlt">atom</span> absorption is found elastically and thermodynamically stable. The calculated absorption energy shows that H is more energetically stable in the bridge and octahedral site in MAl and M3Al alloys, respectively. Hydrogen <span class="hlt">atoms</span> absorption is expanded and brittle the studied host alloys. The ability of absorption of H <span class="hlt">atom</span> at more than one site in the MAl alloy is found energetically and thermodynamically stable. The H adsorption on the variant surfaces of MAl (001) is predicted too. Fourfold and top sites are found more energetically stable to adsorbed the H <span class="hlt">atom</span> on the above surface layer of H/MAl-M and H/MAl-Al, respectively. The obvious changes are observed in the interlayer spacing for studied surfaces which yields to decrease the LDOS and <span class="hlt">magnetic</span> moments of the surface and subsurface layers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5257938','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5257938"><span id="translatedtitle">Construction and test results of a compact 0. 8 meter <span class="hlt">warm</span> bore 1. 5 Tesla high homogeneity superconducting <span class="hlt">magnet</span> for MR spectroscopy</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Nenonen, S. ); Friman, E.; Ikkala, O. ); Islander, S. ); Seppala, H.; Pekola, J. ); Sariala, A. ); Collan, H.K. )</p> <p>1992-01-01</p> <p>a superconducting <span class="hlt">magnet</span> aimed at whole body MRI and spectroscopic studies was designed, constructed and tested. <span class="hlt">Magnet</span> was wound with a 2 mm diameter NbTi/Cu multifilamentary composite conductor. The design field was B{sub 0} = 1.5 T, the design value for field homogeneity {Delta}B/B{sub 0} - 0.1 ppm over a 20 cm diameter spherical volume, and the design value for the field stability dB{sub 0}/dt/B{sub 0} {le} 0.1 ppm/h. During construction of the <span class="hlt">magnet</span>, special emphasis was put into evaluating the winding accuracy which is attainable in practice. Dimensional measurements on the coil were compared with subsequent field measurements. The <span class="hlt">magnet</span> was designed to be fully self-protective in the event of a quench. The quench calculations were verified by test quench measurements. The <span class="hlt">magnet</span> was cooled by immersion in a 300 liter LHe-bath of an annular helium cryostat having an 0.8 m diameter GRP room temperature bore tube, with a 7 l/d LHE boil-off. In this paper constructional and design aspects are discussed and test results are given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080023614','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080023614"><span id="translatedtitle">Actuated <span class="hlt">atomizer</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tilton, Charles (Inventor); Weiler, Jeff (Inventor); Palmer, Randall (Inventor); Appel, Philip (Inventor)</p> <p>2008-01-01</p> <p>An actuated <span class="hlt">atomizer</span> is adapted for spray cooling or other applications wherein a well-developed, homogeneous and generally conical spray mist is required. The actuated <span class="hlt">atomizer</span> includes an outer shell formed by an inner ring; an outer ring; an actuator insert and a cap. A nozzle framework is positioned within the actuator insert. A base of the nozzle framework defines swirl inlets, a swirl chamber and a swirl chamber. A nozzle insert defines a center inlet and feed ports. A spool is positioned within the coil housing, and carries the coil windings having a number of turns calculated to result in a <span class="hlt">magnetic</span> field of sufficient strength to overcome the bias of the spring. A plunger moves in response to the <span class="hlt">magnetic</span> field of the windings. A stop prevents the pintle from being withdrawn excessively. A pintle, positioned by the plunger, moves between first and second positions. In the first position, the head of the pintle blocks the discharge passage of the nozzle framework, thereby preventing the <span class="hlt">atomizer</span> from discharging fluid. In the second position, the pintle is withdrawn from the swirl chamber, allowing the <span class="hlt">atomizer</span> to release <span class="hlt">atomized</span> fluid. A spring biases the pintle to block the discharge passage. The strength of the spring is overcome, however, by the <span class="hlt">magnetic</span> field created by the windings positioned on the spool, which withdraws the plunger into the spool and further compresses the spring.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016FBS....57...71S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016FBS....57...71S"><span id="translatedtitle">The Gaussian <span class="hlt">Atomic</span> Orbital Multiplied by a Field-Dependent Gauge Phase for the Hydrogen Molecular Ion in Non-aligned <span class="hlt">Magnetic</span> Fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Song, Xuanyu; Li, Cun; Wang, Xiaofeng; Qiao, Haoxue</p> <p>2016-01-01</p> <p>We multiply the anisotropic Gaussian <span class="hlt">atomic</span> orbital by a field-dependent gauge phase to describe the wave function for the hydrogen molecular ion in non-aligned <span class="hlt">magnetic</span> fields. With the kind of basis set, the convergence of the total energy at the equilibrium distance for the 1 u state is much improved compared to the same <span class="hlt">atomic</span> orbital without the gauge phase. For 2.35 × 104 ≤ B ≤ 107 T, better total energies of the 1 u state at the corresponding equilibrium are obtained for the deviations 15°-90° of the <span class="hlt">magnetic</span> field relative to the molecular axis. The result also shows that, there is a transition of the equilibrium configuration from the vertical orientation to the parallel orientation with increasing field strength.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950029677&hterms=Atomic+structure&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3D%2528Atomic%2Bstructure%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950029677&hterms=Atomic+structure&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3D%2528Atomic%2Bstructure%2529"><span id="translatedtitle"><span class="hlt">Atomic</span> sulfur: Frequency measurement of the J = 0 left arrow 1 fine-structure transition at 56.3 microns by laser <span class="hlt">magnetic</span> resonance</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Brown, John M.; Evenson, Kenneth M.; Zink, Lyndon R.</p> <p>1994-01-01</p> <p>The J = 0 left arrow 1 fine-structure transition in <span class="hlt">atomic</span> sulfur (S I) in its ground (3)P state has been detected in the laboratory by far-infrared laser <span class="hlt">magnetic</span> resonance. The fine-structure interval has been measured accurately as 5,322,492.9 +/- 2.8 MHz which corresponds to a wavelength of 56.325572 +/- 0.000030 micrometers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhyE...65...24Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhyE...65...24Z"><span id="translatedtitle">Structure, electronic and <span class="hlt">magnetic</span> properties of hexagonal boron nitride sheets doped by 5d transition metal <span class="hlt">atoms</span>: First-principles calculations and molecular orbital analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Zhaofu; Geng, Zhaohui; Cai, Danyun; Pan, Tongxi; Chen, Yixin; Dong, Liyuan; Zhou, Tiege</p> <p>2015-01-01</p> <p>A first-principles calculation based on density functional theory is carried out to reveal the geometry, electronic structures and <span class="hlt">magnetic</span> properties of hexagonal boron nitride sheets (h-BNSs) doped by 5d transitional mental <span class="hlt">atoms</span> (Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au and Hg) at boron-site (B5d) and nitrogen-site (N5d). Results of pure h-BNS, h-BNS with B vacancy (VB) and N vacancy (VN) are also given for comparison. It is shown that all the h-BNSs doped with 5d <span class="hlt">atoms</span> possess a C3v local symmetry except for NLu and NHg which have a clear deviation. For the same 5d dopant, the binding energy of B5d is larger than that of N5d, which indicates the substitution of a 5d <span class="hlt">atom</span> for B is preferred. The total densities of states are presented, where impurity energy levels exist. Besides, the total <span class="hlt">magnetic</span> moments (TMMs) change regularly with the increment of the 5d <span class="hlt">atomic</span> number. Theoretical analyses by molecular orbital under C3v symmetry explain the impurity energy levels and TMMs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/943848','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/943848"><span id="translatedtitle">Neutral <span class="hlt">atom</span> traps.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Pack, Michael Vern</p> <p>2008-12-01</p> <p>This report describes progress in designing a neutral <span class="hlt">atom</span> trap capable of trapping sub millikelvin <span class="hlt">atom</span> in a <span class="hlt">magnetic</span> trap and shuttling the <span class="hlt">atoms</span> across the <span class="hlt">atom</span> chip from a collection area to an optical cavity. The numerical simulation and <span class="hlt">atom</span> chip design are discussed. Also, discussed are preliminary calculations of quantum noise sources in Kerr nonlinear optics measurements based on electromagnetically induced transparency. These types of measurements may be important for quantum nondemolition measurements at the few photon limit.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=climate+AND+marine&pg=2&id=EJ412301','ERIC'); return false;" href="http://eric.ed.gov/?q=climate+AND+marine&pg=2&id=EJ412301"><span id="translatedtitle">Global <span class="hlt">Warming</span> Trends.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Jones, Philip D.; Wigley, Tom M. L.</p> <p>1990-01-01</p> <p>Results from the analysis of land and marine records from the past century are presented. It is indicated that the planet earth has <span class="hlt">warmed</span> about one-half of a degree celsius. The uncertainty of these measurements and future <span class="hlt">warming</span> trends are discussed. (CW)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=11242&keyword=social+AND+web&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=50206637&CFTOKEN=38183703','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=11242&keyword=social+AND+web&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=50206637&CFTOKEN=38183703"><span id="translatedtitle">EPA GLOBAL <span class="hlt">WARMING</span> WEBSITE</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>The U.S. EPA Global <span class="hlt">Warming</span> Site strives to present or direct viewers to the most timely social, scientific, and logistic information available on the global <span class="hlt">warming</span> issue. The site offers links to related sites as well as its own selection of material, which is expected to grow ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JChPh.137j4302T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JChPh.137j4302T"><span id="translatedtitle">Cold collisions of polyatomic molecular radicals with S-state <span class="hlt">atoms</span> in a <span class="hlt">magnetic</span> field: An ab initio study of He + CH2(X~) collisions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tscherbul, T. V.; Grinev, T. A.; Yu, H.-G.; Dalgarno, A.; K?os, Jacek; Ma, Lifang; Alexander, Millard H.</p> <p>2012-09-01</p> <p>We develop a rigorous quantum mechanical theory for collisions of polyatomic molecular radicals with S-state <span class="hlt">atoms</span> in the presence of an external <span class="hlt">magnetic</span> field. The theory is based on a fully uncoupled space-fixed basis set representation of the multichannel scattering wave function. Explicit expressions are presented for the matrix elements of the scattering Hamiltonian for spin-1/2 and spin-1 polyatomic molecular radicals interacting with structureless targets. The theory is applied to calculate the cross sections and thermal rate constants for spin relaxation in low-temperature collisions of the prototypical organic molecule methylene [CH_2(tilde{X}^3B_1)] with He <span class="hlt">atoms</span>. To this end, two accurate three-dimensional potential energy surfaces (PESs) of the He-CH_2(tilde{X}^3B_1) complex are developed using the state-of-the-art coupled-cluster method including single and double excitations along with a perturbative correction for triple excitations and large basis sets. Both PESs exhibit shallow minima and are weakly anisotropic. Our calculations show that spin relaxation in collisions of CH2, CHD, and CD2 molecules with He <span class="hlt">atoms</span> occurs at a much slower rate than elastic scattering over a large range of temperatures (1 ?K-1 K) and <span class="hlt">magnetic</span> fields (0.01-1 T), suggesting excellent prospects for cryogenic helium buffer-gas cooling of ground-state ortho-CH_2(tilde{X}^3B_1) molecules in a <span class="hlt">magnetic</span> trap. Furthermore, we find that ortho-CH2 undergoes collision-induced spin relaxation much more slowly than para-CH2, which indicates that <span class="hlt">magnetic</span> trapping can be used to separate nuclear spin isomers of open-shell polyatomic molecules.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22979854','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22979854"><span id="translatedtitle">Cold collisions of polyatomic molecular radicals with S-state <span class="hlt">atoms</span> in a <span class="hlt">magnetic</span> field: an ab initio study of He + CH2(X) collisions.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tscherbul, T V; Grinev, T A; Yu, H-G; Dalgarno, A; K?os, Jacek; Ma, Lifang; Alexander, Millard H</p> <p>2012-09-14</p> <p>We develop a rigorous quantum mechanical theory for collisions of polyatomic molecular radicals with S-state <span class="hlt">atoms</span> in the presence of an external <span class="hlt">magnetic</span> field. The theory is based on a fully uncoupled space-fixed basis set representation of the multichannel scattering wave function. Explicit expressions are presented for the matrix elements of the scattering Hamiltonian for spin-1/2 and spin-1 polyatomic molecular radicals interacting with structureless targets. The theory is applied to calculate the cross sections and thermal rate constants for spin relaxation in low-temperature collisions of the prototypical organic molecule methylene [CH(2)(X(3)B(1))] with He <span class="hlt">atoms</span>. To this end, two accurate three-dimensional potential energy surfaces (PESs) of the He-CH(2)(X(3)B(1)) complex are developed using the state-of-the-art coupled-cluster method including single and double excitations along with a perturbative correction for triple excitations and large basis sets. Both PESs exhibit shallow minima and are weakly anisotropic. Our calculations show that spin relaxation in collisions of CH(2), CHD, and CD(2) molecules with He <span class="hlt">atoms</span> occurs at a much slower rate than elastic scattering over a large range of temperatures (1 ?K-1 K) and <span class="hlt">magnetic</span> fields (0.01-1 T), suggesting excellent prospects for cryogenic helium buffer-gas cooling of ground-state ortho-CH(2)(X(3)B(1)) molecules in a <span class="hlt">magnetic</span> trap. Furthermore, we find that ortho-CH(2) undergoes collision-induced spin relaxation much more slowly than para-CH(2), which indicates that <span class="hlt">magnetic</span> trapping can be used to separate nuclear spin isomers of open-shell polyatomic molecules. PMID:22979854</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JPCM...28a5003W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JPCM...28a5003W"><span id="translatedtitle">Investigation of the <span class="hlt">magnetic</span> dipole field at the <span class="hlt">atomic</span> scale in quasi-one-dimensional paramagnetic conductor Li0.9Mo6O17</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, Guoqing; Ye, Xiao-shan; Zeng, Xianghua; Wu, Bing; Clark, W. G.</p> <p>2016-01-01</p> <p>We report <span class="hlt">magnetic</span> dipole field investigation at the <span class="hlt">atomic</span> scale in a single crystal of quasi-one-dimensional (Q1D) paramagnetic conductor Li0.9Mo6O17, using a paramagnetic electron model and 7Li-NMR spectroscopy measurements with an externally applied <span class="hlt">magnetic</span> field B 0??=??9 T. We find that the <span class="hlt">magnetic</span> dipole field component (B\\parallel\\text{dip} ) parallel to B 0 at the Li site from the Mo electrons has no lattice axial symmetry; it is small around the middle between the lattice a and c axes in the ac-plane with the minimum at the field orientation angle ? =+{{52.5}\\circ} , while the B\\parallel\\text{dip} maximum is at ? =+{{142.5}\\circ} when B 0 is applied perpendicular to b ({{B}0}\\bot b ), where ? ={{0}\\circ} represents the direction of {{B}0}\\parallel c . Further estimation indicates that B\\parallel\\text{dip} has a maximum value of 0.35 G at B 0??=??9 T. By minimizing the potential <span class="hlt">magnetic</span> contributions to the NMR spectra satellites with the NMR spectroscopy measurements at the direction where the value of the <span class="hlt">magnetic</span> dipole field component B\\parallel\\text{dip} is???0, the behavior of the electron charge statics is exhibited. This work demonstrates that the <span class="hlt">magnetic</span> dipole field of the Mo electrons is the dominant source of the local <span class="hlt">magnetic</span> fields at the Li site, and suggests that the unknown metal-insulator crossover at low temperatures is not a charge effect. The work also reveals valuable local electric and <span class="hlt">magnetic</span> field information for further NMR investigation as recently suggested (2012 Phys. Rev. B 85 235128) regarding the unusual properties of the material.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26571041','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26571041"><span id="translatedtitle">Investigation of the <span class="hlt">magnetic</span> dipole field at the <span class="hlt">atomic</span> scale in quasi-one-dimensional paramagnetic conductor Li0.9Mo6O17.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wu, Guoqing; Ye, Xiao-Shan; Zeng, Xianghua; Wu, Bing; Clark, W G</p> <p>2016-01-13</p> <p>We report <span class="hlt">magnetic</span> dipole field investigation at the <span class="hlt">atomic</span> scale in a single crystal of quasi-one-dimensional (Q1D) paramagnetic conductor Li0.9Mo6O17, using a paramagnetic electron model and (7)Li-NMR spectroscopy measurements with an externally applied <span class="hlt">magnetic</span> field B 0??=??9 T. We find that the <span class="hlt">magnetic</span> dipole field component ([Formula: see text]) parallel to B 0 at the Li site from the Mo electrons has no lattice axial symmetry; it is small around the middle between the lattice a and c axes in the ac-plane with the minimum at the field orientation angle [Formula: see text], while the [Formula: see text] maximum is at [Formula: see text] when B 0 is applied perpendicular to b ([Formula: see text]), where [Formula: see text] represents the direction of [Formula: see text]. Further estimation indicates that [Formula: see text] has a maximum value of 0.35 G at B 0??=??9 T. By minimizing the potential <span class="hlt">magnetic</span> contributions to the NMR spectra satellites with the NMR spectroscopy measurements at the direction where the value of the <span class="hlt">magnetic</span> dipole field component [Formula: see text] is???0, the behavior of the electron charge statics is exhibited. This work demonstrates that the <span class="hlt">magnetic</span> dipole field of the Mo electrons is the dominant source of the local <span class="hlt">magnetic</span> fields at the Li site, and suggests that the unknown metal-'insulator' crossover at low temperatures is not a charge effect. The work also reveals valuable local electric and <span class="hlt">magnetic</span> field information for further NMR investigation as recently suggested (2012 Phys. Rev. B 85 235128) regarding the unusual properties of the material. PMID:26571041</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015aska.confE.110R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015aska.confE.110R"><span id="translatedtitle">Measuring <span class="hlt">Magnetic</span> Fields Near and Far with the SKA via the Zeeman Effect</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Robishaw, T.; Green, J.; Surcis, G.; Vlemmings, W. H. T.; Richards, A. M. S.; Etoka, S.; Bourke, T.; Fish, V.; Gray, M. D.; Imai, H.; Kramer, B.; McBride, J.; Momjian, E.; Sarma, A. P.; Zijlstra, A. A.</p> <p></p> <p>The measurement of Zeeman splitting in spectral lines---both in emission and absorption---can provide direct estimates of the <span class="hlt">magnetic</span> field strength and direction in <span class="hlt">atomic</span> and molecular clouds, both in our own Milky Way and in external galaxies. This method will probe the <span class="hlt">magnetic</span> field in the <span class="hlt">warm</span> and cold neutral components of the interstellar medium, providing a complement to the extensive SKA Faraday studies planning to probe the field in the ionized components.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009CoPhC.180..302E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009CoPhC.180..302E"><span id="translatedtitle">A fast parallel code for calculating energies and oscillator strengths of many-electron <span class="hlt">atoms</span> at neutron star <span class="hlt">magnetic</span> field strengths in adiabatic approximation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Engel, D.; Klews, M.; Wunner, G.</p> <p>2009-02-01</p> <p>We have developed a new method for the fast computation of wavelengths and oscillator strengths for medium-Z <span class="hlt">atoms</span> and ions, up to iron, at neutron star <span class="hlt">magnetic</span> field strengths. The method is a parallelized Hartree-Fock approach in adiabatic approximation based on finite-element and B-spline techniques. It turns out that typically 15-20 finite elements are sufficient to calculate energies to within a relative accuracy of 10-5 in 4 or 5 iteration steps using B-splines of 6th order, with parallelization speed-ups of 20 on a 26-processor machine. Results have been obtained for the energies of the ground states and excited levels and for the transition strengths of astrophysically relevant <span class="hlt">atoms</span> and ions in the range Z=2…26 in different ionization stages. Catalogue identifier: AECC_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AECC_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 3845 No. of bytes in distributed program, including test data, etc.: 27 989 Distribution format: tar.gz Programming language: MPI/Fortran 95 and Python Computer: Cluster of 1-26 HP Compaq dc5750 Operating system: Fedora 7 Has the code been vectorised or parallelized?: Yes RAM: 1 GByte Classification: 2.1 External routines: MPI/GFortran, LAPACK, PyLab/Matplotlib Nature of problem: Calculations of synthetic spectra [1] of strongly <span class="hlt">magnetized</span> neutron stars are bedevilled by the lack of data for <span class="hlt">atoms</span> in intense <span class="hlt">magnetic</span> fields. While the behaviour of hydrogen and helium has been investigated in detail (see, e.g., [2]), complete and reliable data for heavier elements, in particular iron, are still missing. Since neutron stars are formed by the collapse of the iron cores of massive stars, it may be assumed that their atmospheres contain an iron plasma. Our objective is to fill the gap and to provide a program which allows users to calculate as comprehensively as possible energies, wavelengths, and oscillator strengths of medium-Z <span class="hlt">atoms</span> and ions up to Z=26 in neutron star <span class="hlt">magnetic</span> field strengths. Obviously, the method for achieving this goal must be highly efficient since for the calculation of synthetic spectra data of many thousands or even millions of <span class="hlt">atomic</span> transitions may be required. Solution method: As in previous work on the problem (cf. [3,7]) we exploit the fact that a strong <span class="hlt">magnetic</span> field results in an approximate decoupling of the dynamics of the electrons parallel and perpendicular to the field. In this adiabatic approximation the single-particle wave functions take the form: ψ(ρ,φ,z)=ϕ(ρ,φ)ṡP(z), where ϕ(ρ,φ) are Landau wave functions, describing the (fast) motion perpendicular to the field, and the P(z) are the longitudinal wave functions, describing the (slow) bound motion along the direction of the field. The spins of the electrons are all aligned antiparallel to the <span class="hlt">magnetic</span> field and need not be accounted for explicitly. The total N-electron wave function is constructed as a Slater determinant of the single-particle wave functions, and the unknown longitudinal wave functions are determined from the Hartree-Fock equations, which follow from inserting the total N-electron wave function into Schrödinger's variational principle for the total energy. The novel feature of our approach [8] is to use finite-element and B-spline techniques to solve the Hartree-Fock equations for <span class="hlt">atoms</span> in strong <span class="hlt">magnetic</span> fields. This is accomplished through the following steps: 1) decomposition of the z-axis into finite elements with quadratically widening element borders; 2) sixth-order B-spline expansion of the single-particle wave functions on the individual finite elements; 3) formulation of the variational principle equivalent to the Hartree-Fock equations in terms of the expansion coefficients. This leads to a simple system of linear equations for the expansion coefficients, which is solved numerically, and, since the direct and exchange interaction potential terms depend on the wave functions, in a self consistent way. The iteration procedure is initialized by distributing the electrons on <span class="hlt">magnetic</span> sublevels according to the level scheme of the hydrogen <span class="hlt">atom</span> in intense <span class="hlt">magnetic</span> fields. To speed up the calculations, the code is parallelized. The parallelization strategy is: a) each processor calculates one or several electrons, depending on the total number of processors, b) single-particle wave functions are broadcast from each processor to every other processor. As the coefficient vectors in the B-spline basis are small (dim≈20-25), there is only little communication between the nodes. Typical speedups by a factor of 20 are obtained on a 26-processor cluster of HP Compaq dc57750. Running time: The test runs provided only require a few seconds using 2 processors. References: [1] K. Werner, S. Dreizler, The classical stellar atmosphere problem, in: H. Riffert, K. Werner (Eds.), Computational Astrophysics, Computational and Applied Mathematics, Elsevier, 1998. [2] H. Ruder, G. Wunner, H. Herold, F. Geyer, <span class="hlt">Atoms</span> in Strong <span class="hlt">Magnetic</span> Fields, Springer, Heidelberg, 1994. [3] P.B. Jones, Mon. Not. R. Astron. Soc. 216 (1985) 503. [4] D. Neuhauser, K. Langanke, S.E. Koonin, Phys. Rev. A 33 (1986) 2084. [5] M.C. Miller, D. Neuhauser, Mon. Not. R. Astron. Soc. 253 (1991) 107. [6] M. Rajagopal, R.W. Romani, M.C. Miller, Astrophys. J. 479 (1997) 347. [7] K. Mori, C.J. Hailey, Astrophys. J. 564 (2002) 914. [8] M. Klews, Discretization methods for the investigation of <span class="hlt">atoms</span> in time dependent electric fields, and in extremely strong <span class="hlt">magnetic</span> fields (in German), Doctoral Thesis, University of Tübingen, 2003, http://www.theo1.physik.unistuttgart. de/forschung/sfb382a15/klews2003.ps.gz.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhLA..379.2370Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhLA..379.2370Z"><span id="translatedtitle">Complex <span class="hlt">magnetism</span> of Mn-based Pnma ternary alloys: Three exchange interactions induced by the position of Mn <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhou, X. G.; Shi, Y. G.; Zhu, Y.; Shi, D. N.</p> <p>2015-10-01</p> <p>Density functional theory was used to study the relationship between <span class="hlt">magnetism</span> and structure of Mn-based Pnma ternary alloys (MMnX). The <span class="hlt">magnetic</span> states in these alloys largely rely on the value of Mn-Mn-Mn bond angle. There were two apparent critical bond angles being formed among ferromagnetic double exchange, anti-ferromagnetic super-exchange, and ferromagnetic super-exchange. Results indicated that the <span class="hlt">magnetic</span> exchange interaction showed continuous transition in MMnX. The <span class="hlt">magnetism</span> of MMnX was found to function on the basis of the relationship between bond angle and <span class="hlt">magnetic</span> exchange interaction. This work provides a novel way of designing multi-functional materials made of MMnX with pointed <span class="hlt">magnetic</span> exchange interaction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996JMMM..156..211B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996JMMM..156..211B"><span id="translatedtitle">Variations in the <span class="hlt">magnetic</span> properties of ultrathin Co films due to the adsorption of non-<span class="hlt">magnetic</span> metal <span class="hlt">atoms</span> at the Co/vacuum interface</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Buckley, M. E.; Hope, S.; Schumann, F. O.; Bland, J. A. C.</p> <p>1996-04-01</p> <p>The <span class="hlt">magnetic</span> properties of ultrathin Co/Cu films are strongly dependent on the nature of the interfaces. Using the magneto-optical Kerr effect, we report drastic effects due to the adsorption of sub-monolayer quantities of non-<span class="hlt">magnetic</span> metals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JAP...113j3908N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JAP...113j3908N"><span id="translatedtitle">Surface morphology and <span class="hlt">atomic</span> structure of thin layers of Fe3Si on GaAs(001) and their <span class="hlt">magnetic</span> properties</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Noor, S.; Barsukov, I.; Özkan, M. S.; Elbers, L.; Melnichak, N.; Lindner, J.; Farle, M.; Köhler, U.</p> <p>2013-03-01</p> <p>The structural and <span class="hlt">magnetic</span> properties of ultrathin near-stoichiometric Fe3Si layers on GaAs(001) are investigated after using scanning tunneling microscopy (STM) analysis to optimize the deposition process. This includes <span class="hlt">atomic</span> resolution imaging of the surface as measured by STM revealing the <span class="hlt">atomic</span> ordering and characteristic defects in the topmost layers. Emphasis is laid on connections between the layer morphology and its <span class="hlt">magnetic</span> properties, which are analysed by in situ MOKE, FMR, and SQUID magnetometry. Upon nucleation, the Fe3Si islands behave like superparamagnetic nanoparticles where we find a quantitative agreement between the size of the nanoparticles and their superspin. At higher coverage, the Fe3Si layers show ferromagnetic behaviour. Here, we investigate the superposition of the magnetocrystalline and the uniaxial anisotropies where the latter can be excluded to be caused by shape anisotropy. Furthermore, an unexpected increase of the <span class="hlt">magnetic</span> moment towards low coverage can be observed which apart from an increased orbital moment can be attributed to an increased step density.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/46040','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/46040"><span id="translatedtitle">Global <span class="hlt">warming</span> elucidated</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Shen, S.</p> <p>1995-03-01</p> <p>The meaning of global <span class="hlt">warming</span> and its relevance to everyday life is explained. Simple thermodynamics is used to predict an oscillatory nature of the change in climate due to global <span class="hlt">warming</span>. Global <span class="hlt">warming</span> causes extreme events and bad weather in the near term. In the long term it may cause the earth to transition to another equilibrium state through many oscillation in climatic patterns. The magnitudes of these oscillations could easily exceed the difference between the end points. The author further explains why many no longer fully understands the nature and magnitudes of common phenomena such as storms and wind speeds because of these oscillations, and the absorptive properties of clouds. The author links the increase in duration of the El Nino to global <span class="hlt">warming</span>, and further predicts public health risks as the earth transitions to another equilibrium state in its young history.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=dinosaurs&pg=4&id=EJ658270','ERIC'); return false;" href="http://eric.ed.gov/?q=dinosaurs&pg=4&id=EJ658270"><span id="translatedtitle"><span class="hlt">Warm</span> and Cool Dinosaurs.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Mannlein, Sally</p> <p>2001-01-01</p> <p>Presents an art activity in which first grade students draw dinosaurs in order to learn about the concept of <span class="hlt">warm</span> and cool colors. Explains how the activity also helped the students learn about the concept of distance when drawing. (CMK)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150000726','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150000726"><span id="translatedtitle">Reconciling <span class="hlt">Warming</span> Trends</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schmidt, Gavin A.; Shindell, Drew T.; Tsigaridis, Konstantinos</p> <p>2014-01-01</p> <p>Climate models projected stronger <span class="hlt">warming</span> over the past 15 years than has been seen in observations. Conspiring factors of errors in volcanic and solar inputs, representations of aerosols, and El NiNo evolution, may explain most of the discrepancy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21069827','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21069827"><span id="translatedtitle">Existence and stability of alternative ion-acoustic solitary wave solution of the combined MKdV-KdV-ZK equation in a <span class="hlt">magnetized</span> nonthermal plasma consisting of <span class="hlt">warm</span> adiabatic ions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Das, Jayasree; Bandyopadhyay, Anup; Das, K. P.</p> <p>2007-09-15</p> <p>The purpose of this paper is to present the recent work of Das et al. [J. Plasma Phys. 72, 587 (2006)] on the existence and stability of the alternative solitary wave solution of fixed width of the combined MKdV-KdV-ZK (Modified Korteweg-de Vries-Korteweg-de Vries-Zakharov-Kuznetsov) equation for the ion-acoustic wave in a <span class="hlt">magnetized</span> nonthermal plasma consisting of <span class="hlt">warm</span> adiabatic ions in a more generalized form. Here we derive the alternative solitary wave solution of variable width instead of fixed width of the combined MKdV-KdV-ZK equation along with the condition for its existence and find that this solution assumes the sech profile of the MKdV-ZK (Modified Korteweg-de Vries-Zakharov-Kuznetsov) equation, when the coefficient of the nonlinear term of the KdV-ZK (Korteweg-de Vries-Zakharov-Kuznetsov) equation tends to zero. The three-dimensional stability analysis of the alternative solitary wave solution of variable width of the combined MKdV-KdV-ZK equation shows that the instability condition and the first order growth rate of instability are exactly the same as those of the solitary wave solution (the sech profile) of the MKdV-ZK equation, when the coefficient of the nonlinear term of the KdV-ZK equation tends to zero.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20974572','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20974572"><span id="translatedtitle">Stark-induced <span class="hlt">magnetic</span> anapole moment in the ground state of the relativistic hydrogenlike <span class="hlt">atom</span>: Application of the Sturmian expansion of the generalized Dirac-Coulomb Green function</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mielewczyk, Krzysztof; Szmytkowski, Radoslaw</p> <p>2006-02-15</p> <p>The Sturmian expansion of the generalized Dirac-Coulomb Green function [R. Szmytkowski, J. Phys. B 30, 825 (1997); R. Szmytkowski,30, 2747(E) (1997)] is used to derive an analytical formula for the static <span class="hlt">magnetic</span> anapole (toroidal dipole) moment induced in the ground state of the relativistic hydrogenlike <span class="hlt">atom</span> by a weak, spatially uniform, static electric field. An expression for the anapole polarizability for the system in question is found. This expression contains a single generalized hypergeometric series {sub 3}F{sub 2} with the unit argument. In the nonrelativistic limit our result agrees with that of Lewis and Blinder [Phys. Rev. A 52, 4439 (1995)].</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20303666','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20303666"><span id="translatedtitle">Identification of <span class="hlt">magnetic</span> properties of few nm sized FePt crystalline particles by characterizing the intrinsic <span class="hlt">atom</span> order using aberration corrected S/TEM.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Biskupek, Johannes; Jinschek, Joerg R; Wiedwald, Ulf; Bendele, Markus; Han, Luyang; Ziemann, Paul; Kaiser, Ute</p> <p>2010-06-01</p> <p>Hard-<span class="hlt">magnetic</span> nanomaterials like nanoparticles of FePt are of great interest because of their promising potential for data storage applications. The <span class="hlt">magnetic</span> properties of FePt structures strongly differ whether the crystal phases are face centered cubic (fcc) or face centered tetragonal (fct). We evaluated aberration corrected HRTEM, electron diffraction and aberration corrected HAADF-STEM as methods to measure the chemical degree of order S that describes the ordering of Pt and Fe <span class="hlt">atoms</span> within the crystals unit cells. S/TEM experiments are accompanied by image calculations. The findings are compared with results obtained from X-ray diffraction on a FePt film. Our results show that STEM is a reasonable fast approach over HRTEM and electron diffraction to locally determine the chemical degree of order S. PMID:20303666</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22395714','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22395714"><span id="translatedtitle">Inhomogeneous broadening of optically detected <span class="hlt">magnetic</span> resonance of the ensembles of nitrogen-vacancy centers in diamond by interstitial carbon <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Levchenko, A. O. Vasil'ev, V. V.; Zibrov, S. A.; Zibrov, A. S.; Sivak, A. V.; Fedotov, I. V.</p> <p>2015-03-09</p> <p>We study the impact of the negatively charged nitrogen-vacancy (NV{sup –}) center density on the lattice strain resulting in the splitting of the optically detected <span class="hlt">magnetic</span> resonance of HPHT diamond. A simple model, taking into account the presence of the interstitial carbon <span class="hlt">atoms</span>, acting like a wedge force on the crystal lattice, explains the broadening and splitting of the optically detected <span class="hlt">magnetic</span> resonance of the ensemble of NV{sup –} centers at densities within the range of 10{sup 13} ÷ 10{sup 14 }cm{sup −3}. This model uses a complete generalized spin Hamiltonian, takes into account the strain-effect of each center in the ensemble and gives good agreement with experimental data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25679721','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25679721"><span id="translatedtitle">Resistivity saturation in <span class="hlt">warm</span> dense matter.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Faussurier, Grald; Blancard, Christophe</p> <p>2015-01-01</p> <p>Electrical resistivity is shown to saturate in solid-density aluminum in the <span class="hlt">warm</span> dense matter regime. Calculations are done using the average-<span class="hlt">atom</span> model SCAALP and the finite-temperature Ziman-Evans formula for electrical resistivity. The mean free path is estimated using the Drude law. This mean free path is shown to present a minimum of the order of the interatomic spacing. PMID:25679721</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvE..91a3105F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvE..91a3105F"><span id="translatedtitle">Resistivity saturation in <span class="hlt">warm</span> dense matter</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Faussurier, Grald; Blancard, Christophe</p> <p>2015-01-01</p> <p>Electrical resistivity is shown to saturate in solid-density aluminum in the <span class="hlt">warm</span> dense matter regime. Calculations are done using the average-<span class="hlt">atom</span> model SCAALP and the finite-temperature Ziman-Evans formula for electrical resistivity. The mean free path is estimated using the Drude law. This mean free path is shown to present a minimum of the order of the interatomic spacing.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/doepatents/biblio/868364','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/doepatents/biblio/868364"><span id="translatedtitle"><span class="hlt">Atomizing</span> nozzle and process</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Anderson, Iver E. (Ames, IA); Figliola, Richard S. (Central, SC); Molnar, Holly M. (Palm Bay, FL)</p> <p>1992-06-30</p> <p>High pressure <span class="hlt">atomizing</span> nozzle includes a high pressure gas manifold having a divergent expansion chamber between a gas inlet and arcuate manifold segment to minimize standing shock wave patterns in the manifold and thereby improve filling of the manifold with high pressure gas for improved melt <span class="hlt">atomization</span>. The <span class="hlt">atomizing</span> nozzle is especially useful in <span class="hlt">atomizing</span> rare earth-transition metal alloys to form fine powder particles wherein a majority of the powder particles exhibit particle sizes having near-optimum <span class="hlt">magnetic</span> properties.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6303827','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/6303827"><span id="translatedtitle"><span class="hlt">Atomizing</span> nozzle and process</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Anderson, I.E.; Figliola, R.S.; Molnar, H.M.</p> <p>1993-07-20</p> <p>High pressure <span class="hlt">atomizing</span> nozzle includes a high pressure gas manifold having a divergent expansion chamber between a gas inlet and arcuate manifold segment to minimize standing shock wave patterns in the manifold and thereby improve filling of the manifold with high pressure gas for improved melt <span class="hlt">atomization</span>. The <span class="hlt">atomizing</span> nozzle is especially useful in <span class="hlt">atomizing</span> rare earth-transition metal alloys to form fine powder particles wherein a majority of the powder particles exhibit particle sizes having near-optimum <span class="hlt">magnetic</span> properties.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6914531','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6914531"><span id="translatedtitle">Global <span class="hlt">warming</span> on trial</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Broeker, W.S.</p> <p>1992-04-01</p> <p>Jim Hansen, a climatologist at NASA's Goddard Space Institute, is convinced that the earth's temperature is rising and places the blame on the buildup of greenhouse gases in the atmosphere. Unconvinced, John Sununu, former White House chief of staff, doubts that the <span class="hlt">warming</span> will be great enough to produce serious threat and fears that measures to reduce the emissions would throw a wrench into the gears that drive the Unites States' troubled economy. During his three years at the White House, Sununu's view prevailed, and although his role in the debate has diminished, others continue to cast doubt on the reality of global <span class="hlt">warming</span>. A new lobbying group called the Climate Council has been created to do just this. Burning fossil fuels is not the only problem; a fifth of emissions of carbon dioxide now come from clearing and burning forests. Scientists are also tracking a host of other greenhouse gases that emanate from a variety of human activities; the <span class="hlt">warming</span> effect of methane, chlorofluorocarbons and nitrous oxide combined equals that of carbon dioxide. Although the current <span class="hlt">warming</span> from these gases may be difficult to detect against the background noise of natural climate variation, most climatologists are certain that as the gases continue to accumulate, increases in the earth's temperature will become evident even to skeptics. If the reality of global <span class="hlt">warming</span> were put on trial, each side would have trouble making its case. Jim Hansen's side could not prove beyond a reasonable doubt that carbon dioxide and other greenhouse gases have <span class="hlt">warmed</span> the planet. But neither could John Sununu's side prove beyond a reasonable doubt that the <span class="hlt">warming</span> expected from greenhouse gases has not occurred. To see why each side would have difficulty proving its case, this article reviews the arguments that might be presented in such a hearing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/153561','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/153561"><span id="translatedtitle">Long range global <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Rolle, K.C.; Pulkrabek, W.W.; Fiedler, R.A.</p> <p>1995-12-31</p> <p>This paper explores one of the causes of global <span class="hlt">warming</span> that is often overlooked, the direct heating of the environment by engineering systems. Most research and studies of global <span class="hlt">warming</span> concentrate on the modification that is occurring to atmospheric air as a result of pollution gases being added by various systems; i.e., refrigerants, nitrogen oxides, ozone, hydrocarbons, halon, and others. This modification affects the thermal radiation balance between earth, sun and space, resulting in a decrease of radiation outflow and a slow rise in the earths steady state temperature. For this reason the solution to the problem is perceived as one of cleaning up the processes and effluents that are discharged into the environment. In this paper arguments are presented that suggest, that there is a far more serious cause for global <span class="hlt">warming</span> that will manifest itself in the next two or three centuries; direct heating from the exponential growth of energy usage by humankind. Because this is a minor contributor to the global <span class="hlt">warming</span> problem at present, it is overlooked or ignored. Energy use from the combustion of fuels and from the output of nuclear reactions eventually is manifest as <span class="hlt">warming</span> of the surroundings. Thus, as energy is used at an ever increasing rate the consequent global <span class="hlt">warming</span> also increases at an ever increasing rate. Eventually this rate will become equal to a few percent of solar radiation. When this happens the earths temperature will have risen by several degrees with catastrophic results. The trends in world energy use are reviewed and some mathematical models are presented to suggest future scenarios. These models can be used to predict when the global <span class="hlt">warming</span> problem will become undeniably apparent, when it will become critical, and when it will become catastrophic.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20982116','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20982116"><span id="translatedtitle">Ultracold <span class="hlt">atom</span>-molecule collisions and bound states in <span class="hlt">magnetic</span> fields: Tuning zero-energy Feshbach resonances in He-NH ({sup 3}{sigma}{sup -})</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gonzalez-Martinez, Maykel Leonardo; Hutson, Jeremy M.</p> <p>2007-02-15</p> <p>We have generalized the BOUND and MOLSCAT packages to allow calculations in basis sets where the monomer Hamiltonians are off diagonal and used this capability to carry out bound-state and scattering calculations on {sup 3}He-NH and {sup 4}He-NH as a function of <span class="hlt">magnetic</span> field. Following the bound-state energies to the point where they cross thresholds gives very precise predictions of the <span class="hlt">magnetic</span> fields at which zero-energy Feshbach resonances occur. We have used this to locate and characterize two very narrow Feshbach resonances in {sup 3}He-NH. Such resonances can be used to tune elastic and inelastic collision cross sections, and sweeping the <span class="hlt">magnetic</span> field across them will allow a form of quantum control in which separated <span class="hlt">atoms</span> and molecules are associated to form complexes. For the first resonance, where only elastic scattering is possible, the scattering length shows a pole as a function of <span class="hlt">magnetic</span> field and there is a very large peak in the elastic cross section. For the second resonance, however, inelastic scattering is also possible. In this case the pole in the scattering length is dramatically suppressed and the cross sections show relatively small peaks. The peak suppression is expected to be even larger in systems with stronger inelasticity. The results suggest that calculations on ultracold molecular inelastic collisions may be much less sensitive to details of the potential energy surface than has been believed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014RScI...85h6103M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014RScI...85h6103M"><span id="translatedtitle">Note: High turn density <span class="hlt">magnetic</span> coils with improved low pressure water cooling for use in <span class="hlt">atom</span> optics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McKay Parry, Nicholas; Baker, Mark; Neely, Tyler; Carey, Thomas; Bell, Thomas; Rubinsztein-Dunlop, Halina</p> <p>2014-08-01</p> <p>We describe a <span class="hlt">magnetic</span> coil design utilizing concentrically wound electro-<span class="hlt">magnetic</span> insulating (EMI) foil (25.4 ?m Kapton backing and 127 ?m thick layers). The <span class="hlt">magnetic</span> coils are easily configurable for different coil sizes, while providing large surfaces for low-pressure (0.12 bar) water cooling. The coils have turn densities of 5 mm-1 and achieve a maximum of 377 G at 2.1 kW driving power, measured at a distance 37.9 mm from the axial center of the coil. The coils achieve a steady-state temperature increase of 36.7C/kW.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997JMMM..166..207D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997JMMM..166..207D"><span id="translatedtitle">Influence of a Si <span class="hlt">atom</span> admixture on the <span class="hlt">magnetic</span> properties of SmMn 2Ge 2</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Duraj, R.; Duraj, M.; Szytu?a, A.</p> <p>1997-02-01</p> <p>The <span class="hlt">magnetic</span> properties of SmMn 2(Ge 1- xSi x) 2 for 0 ? x ? 0.2 are reported. The <span class="hlt">magnetic</span> ( x,T) phase diagram has been determined. The pressure effect on the <span class="hlt">magnetic</span> phase transition of SmMn 2(Ge 0.8Si 0.2) 2 has been measured. The values of d TC/d P, d T2/d P and d TN/d P were found to be - 18 4, 165 20 and 11 3 K/GPa, respectively. The ( P, T) diagram has also been determined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1069121','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1069121"><span id="translatedtitle"><span class="hlt">Atomic</span> magnetometer</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Schwindt, Peter; Johnson, Cort N.</p> <p>2012-07-03</p> <p>An <span class="hlt">atomic</span> magnetometer is disclosed which uses a pump light beam at a D1 or D2 transition of an alkali metal vapor to <span class="hlt">magnetically</span> polarize the vapor in a heated cell, and a probe light beam at a different D2 or D1 transition to sense the <span class="hlt">magnetic</span> field via a polarization rotation of the probe light beam. The pump and probe light beams are both directed along substantially the same optical path through an optical waveplate and through the heated cell to an optical filter which blocks the pump light beam while transmitting the probe light beam to one or more photodetectors which generate electrical signals to sense the <span class="hlt">magnetic</span> field. The optical waveplate functions as a quarter waveplate to circularly polarize the pump light beam, and as a half waveplate to maintain the probe light beam linearly polarized.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NatCC...5..849C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NatCC...5..849C"><span id="translatedtitle">ENSO and greenhouse <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cai, Wenju; Santoso, Agus; Wang, Guojian; Yeh, Sang-Wook; An, Soon-Il; Cobb, Kim M.; Collins, Mat; Guilyardi, Eric; Jin, Fei-Fei; Kug, Jong-Seong; Lengaigne, Matthieu; McPhaden, Michael J.; Takahashi, Ken; Timmermann, Axel; Vecchi, Gabriel; Watanabe, Masahiro; Wu, Lixin</p> <p>2015-09-01</p> <p>The El Nio/Southern Oscillation (ENSO) is the dominant climate phenomenon affecting extreme weather conditions worldwide. Its response to greenhouse <span class="hlt">warming</span> has challenged scientists for decades, despite model agreement on projected changes in mean state. Recent studies have provided new insights into the elusive links between changes in ENSO and in the mean state of the Pacific climate. The projected slow-down in Walker circulation is expected to weaken equatorial Pacific Ocean currents, boosting the occurrences of eastward-propagating <span class="hlt">warm</span> surface anomalies that characterize observed extreme El Nio events. Accelerated equatorial Pacific <span class="hlt">warming</span>, particularly in the east, is expected to induce extreme rainfall in the eastern equatorial Pacific and extreme equatorward swings of the Pacific convergence zones, both of which are features of extreme El Nio. The frequency of extreme La Nia is also expected to increase in response to more extreme El Nios, an accelerated maritime continent <span class="hlt">warming</span> and surface-intensified ocean <span class="hlt">warming</span>. ENSO-related catastrophic weather events are thus likely to occur more frequently with unabated greenhouse-gas emissions. But model biases and recent observed strengthening of the Walker circulation highlight the need for further testing as new models, observations and insights become available.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AIPA....5j7119L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AIPA....5j7119L"><span id="translatedtitle">Measuring the spin polarization of alkali-metal <span class="hlt">atoms</span> using nuclear <span class="hlt">magnetic</span> resonance frequency shifts of noble gases</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, X. H.; Luo, H.; Qu, T. L.; Yang, K. Y.; Ding, Z. C.</p> <p>2015-10-01</p> <p>We report a novel method of measuring the spin polarization of alkali-metal <span class="hlt">atoms</span> by detecting the NMR frequency shifts of noble gases. We calculated the profile of 87Rb D1 line absorption cross sections. We then measured the absorption profile of the sample cell, from which we calculated the 87Rb number densities at different temperatures. Then we measured the frequency shifts resulted from the spin polarization of the 87Rb <span class="hlt">atoms</span> and calculated its polarization degrees at different temperatures. The behavior of frequency shifts versus temperature in experiment was consistent with theoretical calculation, which may be used as compensative signal for the NMRG closed-loop control system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1988EOSTr..69..820W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1988EOSTr..69..820W"><span id="translatedtitle">Model predicts global <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wainger, Lisa A.</p> <p></p> <p>Global greenhouse <span class="hlt">warming</span> will be clearly identifiable by the 1990s, according to eight scientists who have been studying climate changes using computer models. Researchers at NASA's Goddard Space Flight Center, Goddard Institute for Space Studies, New York, and the Massachusetts Institute of Technology, Cambridge, say that by the 2010s, most of the globe will be experiencing substantial <span class="hlt">warming</span>. The level of <span class="hlt">warming</span> will depend on amounts of trace gases, or greenhouse gases, in the atmosphere.Predictions for the next 70 years are based on computer simulations of Earth's climate. In three runs of the model, James Hansen and his colleagues looked at the effects of changing amounts of atmospheric gases with time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/accomplishments/documents/fullText/ACC0284.pdf','DOE-RDACC'); return false;" href="http://www.osti.gov/accomplishments/documents/fullText/ACC0284.pdf"><span id="translatedtitle">Observation of the Forbidden <span class="hlt">Magnetic</span> Dipole Transition 6{sup 2}P{sub ½} --> 7{sup 2}P{sub ½} in <span class="hlt">Atomic</span> Thallium</span></a></p> <p><a target="_blank" href="http://www.osti.gov/accomplishments/fieldedsearch.html">DOE R&D Accomplishments Database</a></p> <p>Chu, S.</p> <p>1976-10-01</p> <p>A measurement of the 6{sup 2}P{sub ½} --> 7{sup 2}P{sub ½} forbidden <span class="hlt">magnetic</span> dipole matrix element in <span class="hlt">atomic</span> thallium is described. A pulsed, linearly polarized dye laser tuned to the transition frequency is used to excite the thallium vapor from the 6{sup 2}P{sub ½} ground state to the 7{sup 2}P{sub ½} excited state. Interference between the <span class="hlt">magnetic</span> dipole M1 amplitude and a static electric field induced E1 amplitude results in an <span class="hlt">atomic</span> polarization of the 7{sup 2}P{sub ½} state, and the subsequent circular polarization of 535 nm fluorescence. The circular polarization is seen to be proportional to / as expected, and measured for several transitions between hyperfine levels of the 6{sup 2}P{sub ½} and 7{sup 2}P{sub ½} states. The result is = -(2.11 +- 0.30) x 10{sup -5} parallel bar e parallel bar dirac constant/2mc, in agreement with theory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JMMM..401.1123J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JMMM..401.1123J"><span id="translatedtitle">Three-dimensional <span class="hlt">atom</span> probe analysis and <span class="hlt">magnetic</span> properties of Fe85Cu1Si2B8P4 melt spun ribbons</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jafari, S.; Beitollahi, A.; Eftekhari Yekta, B.; Ohkubo, T.; Budinsky, Viktoria; Marsilius, Mie; Mollazadeh, S.; Herzer, Giselher; Hono, K.</p> <p>2016-03-01</p> <p>The effect of phosphorous on the microstructure and <span class="hlt">magnetic</span> properties of as-spun and flash annealed (389-535 °C for 7 s) Fe85Cu1Si2B8P4 melt spun ribbons were investigated by three-dimensional <span class="hlt">atom</span> probe (3DAP) and high resolution transmission electron microscopy (HRTEM) techniques. The formation of quasi-amorphous α -Fe clusters of 3-5 nm size in an amorphous matrix were detected by HRTEM, despite the high quenching rate applied by high wheel speed used. Flash annealing of the as-spun ribbons gave rise to the formation of nanocrystalline α-Fe (Si) phase in amorphous matrix containing Fe, Si, B and P elements as detected by 3DAP. Comparing 3DAP analysis of the samples annealed at 445 °C and 535 °C revealed that the concentration of P and B in amorphous matrix were increased for the latter. Further, it was shown that P hardly solidified into nanocrystalline phase and partitioned in amorphous phase alongside B <span class="hlt">atoms</span> leading to the further stabilization of amorphous matrix as confirmed by 3DAP analysis. The highest magnitude of saturation <span class="hlt">magnetic</span> induction (Bs~1.85 T) and the lowest coercive field (~10-20 A/m) were obtained for the samples annealed above 445 °C, for which noticeable reduction of saturation magnetostriction (λ s) were also detected.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApSS..358..619M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApSS..358..619M"><span id="translatedtitle">Tailoring the electric and <span class="hlt">magnetic</span> properties of submicron-sized metallic multilayered systems by TVA <span class="hlt">atomic</span> inter-diffusion engineered processes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miculescu, F.; Jepu, I.; Stan, G. E.; Miculescu, M.; Voicu, S. I.; Cotrut, C.; Pisu, T. Machedon; Ciuca, S.</p> <p>2015-12-01</p> <p>Thermo-ionic Vacuum Arc evaporation method was selected for the synthesis of Fe/Cu/Ni/Cu multilayer structures on Si (1 0 0) substrates. The aim of the study was the preparation and characterization of structures featuring a giant magnetoresistance effect. This was accomplished by inducing the formation of nanosized ferromagnetic crystallites in multilayer nonmagnetic solutions via <span class="hlt">atomic</span> inter-diffusion processes by the tuning of deposition parameters. Layer-by-layer and inter-diffused type structures were prepared and comparatively analyzed by scanning electron microscopy, X-ray microanalysis, <span class="hlt">atomic</span> force microscopy, X-ray diffraction and high-resolution transmission electron microscopy coupled with selected area electron diffraction. We presented the influence of the microstructure on electric and <span class="hlt">magnetic</span> properties of the submicron-sized multilayers. The dependence of the electric resistance and the magnetoresistance on the composition, structure, morphology and roughness of the layers was established. We obtained an electric resistance value of 1.22 Ω for the layer-by-layer type structure, and 0.46 Ω for the inter-diffusion designed structure. Using the <span class="hlt">atomic</span> inter-diffusion we succeeded in achieving an improvement of the magnetoresistive effect, from 0.1% to 2.3%.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26406827','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26406827"><span id="translatedtitle">Coherent coupling of alkali <span class="hlt">atoms</span> by random collisions.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Katz, Or; Peleg, Or; Firstenberg, Ofer</p> <p>2015-09-11</p> <p>Random spin-exchange collisions in <span class="hlt">warm</span> alkali vapor cause rapid decoherence and act to equilibrate the spin state of the <span class="hlt">atoms</span> in the vapor. In contrast, here we demonstrate experimentally and theoretically a coherent coupling of one alkali species to another species, mediated by these random collisions. We show that the minor species (potassium) inherits the <span class="hlt">magnetic</span> properties of the dominant species (rubidium), including its lifetime (T_{1}), coherence time (T_{2}), gyromagnetic ratio, and spin-exchange relaxation-free <span class="hlt">magnetic</span>-field threshold. We further show that this coupling can be completely controlled by varying the strength of the <span class="hlt">magnetic</span> field. Finally, we explain these phenomena analytically by mode mixing of the two species via spin-exchange collisions. PMID:26406827</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22340370','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22340370"><span id="translatedtitle">Influence of ball milling on <span class="hlt">atomic</span> structure and <span class="hlt">magnetic</span> properties of Co{sub 40}Fe{sub 22}Ta{sub 8}B{sub 30} glassy alloy</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Taghvaei, Amir Hossein; Stoica, Mihai; Bednar?ik, Jozef; Kaban, Ivan; Shahabi, Hamed Shakur; Khoshkhoo, Mohsen Samadi; Janghorban, Kamal; Eckert, Jrgen</p> <p>2014-06-01</p> <p>The influence of ball milling on the <span class="hlt">atomic</span> structure and <span class="hlt">magnetic</span> properties of the Co{sub 40}Fe{sub 22}Ta{sub 8}B{sub 30} metallic glass with a high thermal stability and excellent soft <span class="hlt">magnetic</span> properties has been investigated. After 14 h of milling, the obtained powders were found to consist mainly of an amorphous phase and a small fraction of the (Co,Fe){sub 21}Ta{sub 2}B{sub 6} nanocrystals. The changes in the reduced pair correlation functions suggest noticeable changes in the <span class="hlt">atomic</span> structure of the amorphous upon ball milling. Furthermore, it has been shown that milling is accompanied by introduction of compressive and dilatational sites in the glassy phase and increasing the fluctuation of the <span class="hlt">atomic</span>-level hydrostatic stress without affecting the coordination number of the nearest neighbors. Ball milling has decreased the thermal stability and significantly affected the <span class="hlt">magnetic</span> properties through increasing the saturation <span class="hlt">magnetization</span>, Curie temperature of the amorphous phase and coercivity. - Highlights: Ball milling affected the <span class="hlt">atomic</span> structure of Co{sub 40}Fe{sub 22}Ta{sub 8}B{sub 30} metallic glass. Mechanically-induced crystallization started after 4 h milling. Milling increased the fluctuation of the <span class="hlt">atomic</span>-level hydrostatic stress in glass. Ball milling influenced the thermal stability and <span class="hlt">magnetic</span> properties.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=talk+AND+women&pg=6&id=EJ1002704','ERIC'); return false;" href="http://eric.ed.gov/?q=talk+AND+women&pg=6&id=EJ1002704"><span id="translatedtitle"><span class="hlt">Warm</span> and Cool Cityscapes</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Jubelirer, Shelly</p> <p>2012-01-01</p> <p>Painting cityscapes is a great way to teach first-grade students about <span class="hlt">warm</span> and cool colors. Before the painting begins, the author and her class have an in-depth discussion about big cities and what types of buildings or structures that might be seen in them. They talk about large apartment and condo buildings, skyscrapers, art museums,</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED263758.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED263758.pdf"><span id="translatedtitle"><span class="hlt">Warming</span> Up to Communication.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Garner, Lucia Caycedo; Rusch, Debbie</p> <p></p> <p>Daily <span class="hlt">warm</span>-up exercises are advocated as a means of bridging the gap between previously unrelated activities outside the classroom and immersion into the second language, relaxing the class, and establishing a mood for communication. Variety, careful preparation, assuring that the students understand the activity, feeling free to discontinue an</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://gallery.usgs.gov/photos/05_13_2014_vBRd7HG665_05_13_2014_1','SCIGOVIMAGE-USGS'); return false;" href="http://gallery.usgs.gov/photos/05_13_2014_vBRd7HG665_05_13_2014_1"><span id="translatedtitle"><span class="hlt">Warm</span> Springs Creek, Idaho</span></a></p> <p><a target="_blank" href="http://gallery.usgs.gov/">USGS Multimedia Gallery</a></p> <p></p> <p></p> <p><span class="hlt">Warm</span> Springs Creek is a tributary of the Big Wood River in south-central Idaho. It is one of eight sites at which the USGS is conducting an ecological assessment during the summer of 2014. Study results will be published in 2015....</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110023746','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110023746"><span id="translatedtitle">Identifying the Molecular Origin of Global <span class="hlt">Warming</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bera, Partha P.; Francisco, Joseph S.; Lee, Timothy J.</p> <p>2009-01-01</p> <p>We have investigated the physical characteristics of greenhouse gases (GHGs) to assess which properties are most important in determining the efficiency of a GHG. Chlorofluorcarbons (CFCs), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), nitrogen fluorides, and various other known atmospheric trace molecules have been included in this study. Compounds containing the halogens F or Cl have in common very polar X-F or X-Cl bonds, particularly the X-F bonds. It is shown that as more F <span class="hlt">atoms</span> bond to the same central <span class="hlt">atom</span>, the bond dipoles become larger as a result of the central <span class="hlt">atom</span> becoming more positive. This leads to a linear increase in the total or integrated XF bond dipole derivatives for the molecule, which leads to a non-linear (quadratic) increase in infrared (IR) intensity. Moreover, virtually all of the X-F bond stretches occur in the atmospheric IR window as opposed to X-H stretches, which do not occur in the atmospheric window. It is concluded that molecules possessing several F <span class="hlt">atoms</span> will always have a large radiative forcing parameter in the calculation of their global <span class="hlt">warming</span> potential. Some of the implications for global <span class="hlt">warming</span> and climate change are discussed.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1088635','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1088635"><span id="translatedtitle">Electronic Structures and <span class="hlt">Magnetic</span> Properties of MoS2 Nanostructures: <span class="hlt">Atomic</span> Defects, Nanoholes, Nanodots and Antidots</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zhou, Yungang; Yang, Ping; Zu, Haoyue; Gao, Fei; Zu, Xiaotao</p> <p>2013-04-24</p> <p>MoS2-based nanostructures, including <span class="hlt">atomic</span> defect, nanohole, nanodot and antidot, are characterized with spin-polarized density functional theory. The S-vacancy defect is more likely to form than the Mo-vacancy defect due to the formation of Mo-Mo metallic bonds. Among different shaped nanoholes and nanodots, triangle ones associated with ferromagnetic characteristic are the most energetically favorable, and exhibit unexpected large spin moment that is scaled linearly with edged length.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011NatPh...7..520S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011NatPh...7..520S"><span id="translatedtitle">Anti-<span class="hlt">atoms</span>: Gotcha!</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Surko, Clifford M.</p> <p>2011-07-01</p> <p>Refined techniques to mix cold antiprotons and positrons in a <span class="hlt">magnetic</span> bottle show that antihydrogen <span class="hlt">atoms</span> can be trapped for 15 minutes -- an improvement of four orders of magnitude over previous experiments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006JQSRT..99..153F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006JQSRT..99..153F"><span id="translatedtitle">Electrical conductivity of <span class="hlt">warm</span> expanded aluminum</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Faussurier, G.; Blancard, C.; Renaudin, P.; Silvestrelli, P. L.</p> <p>2006-05-01</p> <p>The electronic and ionic structures of <span class="hlt">warm</span> expanded aluminum are determined self-consistently using an average-<span class="hlt">atom</span> formalism based on density-functional theory and Gibbs Bogolyubov inequality. Ion configurations are generated using a least-square fit of the pair distribution function deduced from the average-<span class="hlt">atom</span> model calculations. The electrical conductivity of the system is computed from the Kubo Greenwood formula for the optical conductivity implemented in a molecular dynamics scheme based on density-functional theory. This method goes beyond the Ziman approach commonly used in the average-<span class="hlt">atom</span> formalism. Moreover, it is faster than performing ab initio molecular dynamics simulations to obtain ion configurations for the conductivity calculation. Numerical results and comparisons with experiments are presented and discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006APS..MARH15014F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006APS..MARH15014F"><span id="translatedtitle">Electrical conductivity of <span class="hlt">warm</span> expanded aluminum</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Faussurier, Gerald; Blancard, Christophe; Renaudin, Patrick; Silvestrelli, Pier-Luigi</p> <p>2006-03-01</p> <p>The electronic and ionic structures of <span class="hlt">warm</span> expanded aluminum are determined self-consistently using an average-<span class="hlt">atom</span> formalism based on density-functional theory and Gibbs-Bogolyubov inequality. Ion configurations are generated using a least-square fit of the pair distribution function deduced from the average-<span class="hlt">atom</span> model calculations. The electrical conductivity is computed from the Kubo-Greenwood formula for the optical conductivity implemented in a molecular dynamics scheme based on density-functional theory. This method goes beyond the Ziman approach used in the average-<span class="hlt">atom</span> formalism. Moreover, it is faster than performing quantum molecular dynamics simulations to obtain ion configurations for the conductivity calculation. Numerical results and comparisons with experiments are presented and discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006PhRvB..73g5106F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006PhRvB..73g5106F"><span id="translatedtitle">Electrical conductivity of <span class="hlt">warm</span> expanded Al</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Faussurier, G.; Blancard, C.; Renaudin, P.; Silvestrelli, P. L.</p> <p>2006-02-01</p> <p>The electronic and ionic structures of <span class="hlt">warm</span> expanded aluminum are determined self-consistently using an average-<span class="hlt">atom</span> formalism based on density-functional theory and Gibbs-Bogolyubov inequality. Ion configurations are generated using a least-squares fit of the pair distribution function deduced from the average-<span class="hlt">atom</span> model calculations. The electrical conductivity is computed from the Kubo-Greenwood formula for the optical conductivity implemented in a molecular dynamics scheme based on density-functional theory. This method allows us to go beyond the Ziman approach used in the average-<span class="hlt">atom</span> formalism. Moreover, it is faster than performing quantum molecular dynamics simulations to obtain ion configurations for the conductivity calculation. Numerical results and comparisons with experiments are presented and discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20787915','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20787915"><span id="translatedtitle">Electrical conductivity of <span class="hlt">warm</span> expanded Al</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Faussurier, G.; Blancard, C.; Renaudin, P.</p> <p>2006-02-15</p> <p>The electronic and ionic structures of <span class="hlt">warm</span> expanded aluminum are determined self-consistently using an average-<span class="hlt">atom</span> formalism based on density-functional theory and Gibbs-Bogolyubov inequality. Ion configurations are generated using a least-squares fit of the pair distribution function deduced from the average-<span class="hlt">atom</span> model calculations. The electrical conductivity is computed from the Kubo-Greenwood formula for the optical conductivity implemented in a molecular dynamics scheme based on density-functional theory. This method allows us to go beyond the Ziman approach used in the average-<span class="hlt">atom</span> formalism. Moreover, it is faster than performing quantum molecular dynamics simulations to obtain ion configurations for the conductivity calculation. Numerical results and comparisons with experiments are presented and discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NatGe...8...87B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NatGe...8...87B"><span id="translatedtitle">Climate science: Pacemakers of <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brnnimann, Stefan</p> <p>2015-02-01</p> <p>In the first decades of the twentieth century, the Earth <span class="hlt">warmed</span> rapidly. A coral-based climate proxy record of westerly winds over the equatorial Pacific suggests that wind strength and <span class="hlt">warming</span> rate were linked, as they are today.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/850076','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/850076"><span id="translatedtitle">Microstructual investigation of mixed rar earth iron boron processed vis melt-spinning and high-pressure gas-<span class="hlt">atomization</span> for isotrophic bonded permanent <span class="hlt">magnets</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Buelow, Nicholas Lee</p> <p>2005-08-01</p> <p>A solid solution of three rare earths (RE) in the RE{sub 2}Fe{sub 14}B structure have been combined to create the novel mixed rare earth iron boron (MRE{sub 2}Fe{sub 14}B) alloy family. MRE{sub 2}Fe{sub 14}B exhibits reduced temperature dependent <span class="hlt">magnetic</span> properties; remanence and coercivity. The desired form of MRE{sub 2}Fe{sub 14}B is a powder that can be blended with a polymer binder and compression or injection molded to form an isotropic polymer bonded permanent <span class="hlt">magnet</span> (PBM). Commercially, Nd{sub 2}Fe{sub 14}B is the alloy of choice for PBMs. Powders of Nd{sub 2}Fe{sub 14}B are made via melt-spinning as can be MRE{sub 2}Fe{sub 14}B which allows for direct comparisons. MRE{sub 2}Fe{sub 14}B made using melt-spinning at high wheel speeds is overquenched and must be annealed to an optimal hard <span class="hlt">magnetic</span> state. Due to the rare earth content in the MRE{sub 2}Fe{sub 14}B powders, they must be protected from the environment in which they operate. This protection is accomplished by using a modified fluidized bed process to grow a protective fluoride coating nominally 15nm thick, to reduce air oxidation. MRE{sub 2}Fe{sub 14}B has demonstrated reduced temperature dependent <span class="hlt">magnetic</span> properties in ribbon and PBM form. The real challenge has been modifying alloy designs that were successfully melt-spun to be compatible with high-pressure gas-<span class="hlt">atomization</span> (HPGA). The cooling rates in HPGA are lower than melt-spinning, as the powders are quenched via convective cooling, compared to melt-spinning, which quenches initially by conductive cooling. Early alloy designs, in gas <span class="hlt">atomized</span> and melt-spun form, did not have similar phase compositions or microstructures. Alloy additions, such as the addition of zirconium as a nucleation catalyst, were successful in creating similar phases and microstructures in the HPGA powders and melt-spun ribbon of the same MRE{sub 2}Fe{sub 14}B composition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009JChPh.131i5101N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009JChPh.131i5101N"><span id="translatedtitle"><span class="hlt">Atomic</span> resolution protein structure determination by three-dimensional transferred echo double resonance solid-state nuclear <span class="hlt">magnetic</span> resonance spectroscopy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nieuwkoop, Andrew J.; Wylie, Benjamin J.; Franks, W. Trent; Shah, Gautam J.; Rienstra, Chad M.</p> <p>2009-09-01</p> <p>We show that quantitative internuclear N15-C13 distances can be obtained in sufficient quantity to determine a complete, high-resolution structure of a moderately sized protein by magic-angle spinning solid-state NMR spectroscopy. The three-dimensional ZF-TEDOR pulse sequence is employed in combination with sparse labeling of C13 sites in the ?1 domain of the immunoglobulin binding protein G (GB1), as obtained by bacterial expression with 1,3-C13 or 2-C13-glycerol as the C13 source. Quantitative dipolar trajectories are extracted from two-dimensional N15-C13 planes, in which 750 cross peaks are resolved. The experimental data are fit to exact theoretical trajectories for spin clusters (consisting of one C13 and several N15 each), yielding quantitative precision as good as 0.1 for 350 sites, better than 0.3 for another 150, and 1.0 for 150 distances in the range of 5-8 . Along with isotropic chemical shift-based (TALOS) dihedral angle restraints, the distance restraints are incorporated into simulated annealing calculations to yield a highly precise structure (backbone RMSD of 0.250.09 ), which also demonstrates excellent agreement with the most closely related crystal structure of GB1 (2QMT, bbRMSD 0.790.03 ). Moreover, side chain heavy <span class="hlt">atoms</span> are well restrained (0.760.06 total heavy <span class="hlt">atom</span> RMSD). These results demonstrate for the first time that quantitative internuclear distances can be measured throughout an entire solid protein to yield an <span class="hlt">atomic</span>-resolution structure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AmJPh..83..513M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AmJPh..83..513M"><span id="translatedtitle">Analysis of off-axis solenoid fields using the <span class="hlt">magnetic</span> scalar potential: An application to a Zeeman-slower for cold <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Muniz, Srgio R.; Bagnato, Vanderlei S.; Bhattacharya, M.</p> <p>2015-06-01</p> <p>In a region free of currents, magnetostatics can be described by the Laplace equation of a scalar <span class="hlt">magnetic</span> potential, and one can apply the same methods commonly used in electrostatics. Here, we show how to calculate the general vector field inside a real (finite) solenoid, using only the magnitude of the field along the symmetry axis. Our method does not require integration or knowledge of the current distribution and is presented through practical examples, including a nonuniform finite solenoid used to produce cold <span class="hlt">atomic</span> beams via laser cooling. These examples allow educators to discuss the nontrivial calculation of fields off-axis using concepts familiar to most students, while offering the opportunity to introduce themes of current modern research.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhyE...75..169L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhyE...75..169L"><span id="translatedtitle">Spin and orbital <span class="hlt">magnetic</span> moments and spin anisotropy energies of light rare earth <span class="hlt">atoms</span> embedded in graphene: A first-principles study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Ya-Jing; Wang, Min; Tang, Meng-yu; Tian, Xing; Gao, Shan; He, Zhen; Li, Ying; Zhou, Tie-Ge</p> <p>2016-01-01</p> <p>The geometries, electronic structures, spin <span class="hlt">magnetic</span> moments (SMMs), orbital <span class="hlt">magnetic</span> moments (OMMs) and spin anisotropy energies (SAEs) of light rare earth <span class="hlt">atoms</span> (La, Ce, Pr, Nd, Pm, Sm, Eu, and Gd) embedded in graphene were studied by using first-principles calculations based on Density Functional Theory (DFT). The spin-orbital coupling effect was taken into account and GGA+U method was adopted to describe the strongly localized and correlated 4f electrons. There is a significant deformation of the graphene plane after doping and optimization. The deformation of Gd doped graphene is the largest, while Eu the smallest. The results show that the valence is +3 for La, Ce, Pr, Nd, Pm, Sm and Gd, and +2 for Eu. Except Eu and Gd, there are obvious OMMs. When the spin is in the Z direction, the OMMs are -0.941 μB, -1.663 μB, -3.239 μB, -3.276 μB and -3.337 μB for Ce, Pr, Nd, Pm and Sm, respectively, and point the opposite direction of SMMs. All the doped systems except Gd show considerable SAEs. For Ce, Pr, Nd, Pm, Sm, and Eu, the SAEs are -0.928 meV, 20.941 meV, -8.848 meV, 7.855 meV, 75.070 meV and 0.810 meV, respectively. When the spin orientation is different, different orbital angular moments lead to apparent charge density difference of the 4f <span class="hlt">atoms</span>, which can also explain the origin of SAEs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.3397B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.3397B"><span id="translatedtitle">Global <span class="hlt">Warming</span> And Meltwater</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bratu, S.</p> <p>2012-04-01</p> <p>In order to find new approaches and new ideas for my students to appreciate the importance of science in their daily life, I proposed a theme for them to debate. They had to search for global <span class="hlt">warming</span> information and illustrations in the media, and discuss the articles they found in the classroom. This task inspired them to search for new information about this important and timely theme in science. I informed my students that all the best information about global <span class="hlt">warming</span> and meltwater they found would be used in a poster that would help us to update the knowledge base of the Physics laboratory. I guided them to choose the most eloquent images and significant information. Searching and working to create this poster, the students arrived to better appreciate the importance of science in their daily life and to critically evaluate scientific information transmitted via the media. In the poster we created, one can find images, photos and diagrams and some interesting information: Global <span class="hlt">warming</span> refers to the rising average temperature of the Earth's atmosphere and oceans and its projected evolution. In the last 100 years, the Earth's average surface temperature increased by about 0.8 °C with about two thirds of the increase occurring over just the last three decades. <span class="hlt">Warming</span> of the climate system is unequivocal, and scientists are more than 90% certain most of it is caused by increasing concentrations of greenhouse gases produced by human activities such as deforestation and burning fossil fuel. They indicate that during the 21st century the global surface temperature is likely to rise a further 1.1 to 2.9 °C for the lowest emissions scenario and 2.4 to 6.4 °C for the highest predictions. An increase in global temperature will cause sea levels to rise and will change the amount and pattern of precipitation, and potentially result in expansion of subtropical deserts. <span class="hlt">Warming</span> is expected to be strongest in the Arctic and would be associated with continuing decrease of glaciers, permafrost and sea ice. Other likely effects of the <span class="hlt">warming</span> include more frequent occurrences of extreme weather events including heat waves, droughts and heavy rainfall events, species extinctions due to shifting temperature regimes, and changes in agricultural yields. Meltwater is the water released by the melting of snow or ice, including glacial ice and ice shelves in the oceans. Meltwater is often found in the ablation zone of glaciers, where the rate of snow cover is reduced. In a report published in June 2007, the United Nations Environment Program estimated that global <span class="hlt">warming</span> could lead to 40% of the world's population being affected by the loss of glaciers, snow and the associated meltwater in Asia. This is one of many activities of the physics laboratory that the students of our high school are involved in.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1182501-imaging-dirac-mass-disorder-from-magnetic-dopant-atoms-ferromagnetic-topological-insulator-crx-bi0-xte3','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1182501-imaging-dirac-mass-disorder-from-magnetic-dopant-atoms-ferromagnetic-topological-insulator-crx-bi0-xte3"><span id="translatedtitle">Imaging Dirac-mass disorder from <span class="hlt">magnetic</span> dopant <span class="hlt">atoms</span> in the ferromagnetic topological insulator Crx(Bi0.1Sb0.9)2-xTe3</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Lee, Inhee; Kim, Chung Koo; Lee, Jinho; Billinge, Simon J. L.; Zhong, Ruidan D.; Schneeloch, John A.; Liu, Tiansheng S.; Valla, Tonica; Tranquada, John M.; Gu, Genda D.; et al</p> <p>2015-01-20</p> <p>To achieve and use the most exotic electronic phenomena predicted for the surface states of 3D topological insulators (TIs), it is necessary to open a “Dirac-mass gap” in their spectrum by breaking time-reversal symmetry. Use of <span class="hlt">magnetic</span> dopant <span class="hlt">atoms</span> to generate a ferromagnetic state is the most widely applied approach. However, it is unknown how the spatial arrangements of the <span class="hlt">magnetic</span> dopant <span class="hlt">atoms</span> influence the Dirac-mass gap at the <span class="hlt">atomic</span> scale or, conversely, whether the ferromagnetic interactions between dopant <span class="hlt">atoms</span> are influenced by the topological surface states. Here we image the locations of the <span class="hlt">magnetic</span> (Cr) dopant <span class="hlt">atoms</span> in themore » ferromagnetic TI Cr₀.₀₈(Bi₀.₁Sb₀.₉)₁.₉₂Te₃. Simultaneous visualization of the Dirac-mass gap Δ(r) reveals its intense disorder, which we demonstrate is directly related to fluctuations in n(r), the Cr <span class="hlt">atom</span> areal density in the termination layer. We find the relationship of surface-state Fermi wavevectors to the anisotropic structure of Δ(r) not inconsistent with predictions for surface ferromagnetism mediated by those states. Moreover, despite the intense Dirac-mass disorder, the anticipated relationship Δ(r)∝n(r) is confirmed throughout and exhibits an electron–dopant interaction energy J* = 145 meV·nm². In addition, these observations reveal how <span class="hlt">magnetic</span> dopant <span class="hlt">atoms</span> actually generate the TI mass gap locally and that, to achieve the novel physics expected of time-reversal symmetry breaking TI materials, control of the resulting Dirac-mass gap disorder will be essential.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4321315','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4321315"><span id="translatedtitle">Imaging Dirac-mass disorder from <span class="hlt">magnetic</span> dopant <span class="hlt">atoms</span> in the ferromagnetic topological insulator Crx(Bi0.1Sb0.9)2-xTe3</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lee, Inhee; Kim, Chung Koo; Lee, Jinho; Billinge, Simon J. L.; Zhong, Ruidan; Schneeloch, John A.; Liu, Tiansheng; Valla, Tonica; Tranquada, John M.; Gu, Genda; Davis, J. C. Samus</p> <p>2015-01-01</p> <p>To achieve and use the most exotic electronic phenomena predicted for the surface states of 3D topological insulators (TIs), it is necessary to open a Dirac-mass gap in their spectrum by breaking time-reversal symmetry. Use of <span class="hlt">magnetic</span> dopant <span class="hlt">atoms</span> to generate a ferromagnetic state is the most widely applied approach. However, it is unknown how the spatial arrangements of the <span class="hlt">magnetic</span> dopant <span class="hlt">atoms</span> influence the Dirac-mass gap at the <span class="hlt">atomic</span> scale or, conversely, whether the ferromagnetic interactions between dopant <span class="hlt">atoms</span> are influenced by the topological surface states. Here we image the locations of the <span class="hlt">magnetic</span> (Cr) dopant <span class="hlt">atoms</span> in the ferromagnetic TI Cr0.08(Bi0.1Sb0.9)1.92Te3. Simultaneous visualization of the Dirac-mass gap ?(r) reveals its intense disorder, which we demonstrate is directly related to fluctuations in n(r), the Cr <span class="hlt">atom</span> areal density in the termination layer. We find the relationship of surface-state Fermi wavevectors to the anisotropic structure of ?(r) not inconsistent with predictions for surface ferromagnetism mediated by those states. Moreover, despite the intense Dirac-mass disorder, the anticipated relationship ?(r)?n(r) is confirmed throughout and exhibits an electrondopant interaction energy J* = 145 meVnm2. These observations reveal how <span class="hlt">magnetic</span> dopant <span class="hlt">atoms</span> actually generate the TI mass gap locally and that, to achieve the novel physics expected of time-reversal symmetry breaking TI materials, control of the resulting Dirac-mass gap disorder will be essential. PMID:25605947</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012CoPhC.183.1502S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012CoPhC.183.1502S"><span id="translatedtitle">A highly optimized code for calculating <span class="hlt">atomic</span> data at neutron star <span class="hlt">magnetic</span> field strengths using a doubly self-consistent Hartree-Fock-Roothaan method</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schimeczek, C.; Engel, D.; Wunner, G.</p> <p>2012-07-01</p> <p>Our previously published code for calculating energies and bound-bound transitions of medium-Z elements at neutron star <span class="hlt">magnetic</span> field strengths [D. Engel, M. Klews, G. Wunner, Comput. Phys. Comm. 180 (2009) 302-311] was based on the adiabatic approximation. It assumes a complete decoupling of the (fast) gyration of the electrons under the action of the <span class="hlt">magnetic</span> field and the (slow) bound motion along the field under the action of the Coulomb forces. For the single-particle orbitals this implied that each is a product of a Landau state and an (unknown) longitudinal wave function whose B-spline coefficients were determined self-consistently by solving the Hartree-Fock equations for the many-electron problem on a finite-element grid. In the present code we go beyond the adiabatic approximation, by allowing the transverse part of each orbital to be a superposition of Landau states, while assuming that the longitudinal part can be approximated by the same wave function in each Landau level. Inserting this ansatz into the energy variational principle leads to a system of coupled equations in which the B-spline coefficients depend on the weights of the individual Landau states, and vice versa, and which therefore has to be solved in a doubly self-consistent manner. The extended ansatz takes into account the back-reaction of the Coulomb motion of the electrons along the field direction on their motion in the plane perpendicular to the field, an effect which cannot be captured by the adiabatic approximation. The new code allows for the inclusion of up to 8 Landau levels. This reduces the relative error of energy values as compared to the adiabatic approximation results by typically a factor of three (1/3 of the original error), and yields accurate results also in regions of lower neutron star <span class="hlt">magnetic</span> field strengths where the adiabatic approximation fails. Further improvements in the code are a more sophisticated choice of the initial wave functions, which takes into account the shielding of the core potential for outer electrons by inner electrons, and an optimal finite-element decomposition of each individual longitudinal wave function. These measures largely enhance the convergence properties compared to the previous code, and lead to speed-ups by factors up to two orders of magnitude compared with the implementation of the Hartree-Fock-Roothaan method used by Engel and Wunner in [D. Engel, G. Wunner, Phys. Rev. A 78 (2008) 032515]. New version program summaryProgram title: HFFER II Catalogue identifier: AECC_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AECC_v2_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: v 55 130 No. of bytes in distributed program, including test data, etc.: 293 700 Distribution format: tar.gz Programming language: Fortran 95 Computer: Cluster of 1-13 HP Compaq dc5750 Operating system: Linux Has the code been vectorized or parallelized?: Yes, parallelized using MPI directives. RAM: 1 GByte per node Classification: 2.1 External routines: MPI/GFortran, LAPACK, BLAS, FMlib (included in the package) Catalogue identifier of previous version: AECC_v1_0 Journal reference of previous version: Comput. Phys. Comm. 180 (2009) 302 Does the new version supersede the previous version?: Yes Nature of problem: Quantitative modellings of features observed in the X-ray spectra of isolated <span class="hlt">magnetic</span> neutron stars are hampered by the lack of sufficiently large and accurate databases for <span class="hlt">atoms</span> and ions up to the last fusion product, iron, at strong <span class="hlt">magnetic</span> field strengths. Our code is intended to provide a powerful tool for calculating energies and oscillator strengths of medium-Z <span class="hlt">atoms</span> and ions at neutron star <span class="hlt">magnetic</span> field strengths with sufficient accuracy in a routine way to create such databases. Solution method: The Slater determinants of the <span class="hlt">atomic</span> wave functions are constructed from single-particle orbitals ψi which are products of a wave function in the z direction (the direction of the <span class="hlt">magnetic</span> field) and an expansion of the wave function perpendicular to the direction of the <span class="hlt">magnetic</span> field in terms of Landau states, ψi(ρ,φ,z)=Pi(z)∑n=0NLtinϕni(ρ,φ). The tin are expansion coefficients, and the expansion is cut off at some maximum Landau level quantum number n=NL. In the previous version of the code only the lowest Landau level was included (NL=0), in the new version NL can take values of up to 7. As in the previous version of the code, the longitudinal wave functions are expanded in terms of sixth-order B-splines on finite elements on the z axis, with a combination of equidistant and quadratically widening element borders. Both the B-spline expansion coefficients and the Landau weights tin of all orbitals have to be determined in a doubly self-consistent way: For a given set of Landau weights tin, the system of linear equations for the B-spline expansion coefficients, which is equivalent to the Hartree-Fock equations for the longitudinal wave functions, is solved numerically. In the second step, for frozen B-spline coefficients new Landau weights are determined by minimizing the total energy with respect to the Landau expansion coefficients. Both steps require solving non-linear eigenvalue problems of Roothaan type. The procedure is repeated until convergence of both the B-spline coefficients and the Landau weights is achieved. Reasons for new version: The former version of the code was restricted to the adiabatic approximation, which assumes the quantum dynamics of the electrons in the plane perpendicular to the <span class="hlt">magnetic</span> field to be fixed in the lowest Landau level, n=0. This approximation is valid only if the <span class="hlt">magnetic</span> field strengths are large compared to the reference <span class="hlt">magnetic</span> field BZ, for a nuclear charge Z,BZ=Z24.70108×105 T. Summary of revisions: In the new version, the transverse parts of the orbitals are expanded in terms of Landau states up to n=7, and the expansion coefficients are determined, together with the longitudinal wave functions, in a doubly self-consistent way. Thus the back-reaction of the quantum dynamics along the <span class="hlt">magnetic</span> field direction on the quantum dynamics in the plane perpendicular to it is taken into account. The new ansatz not only increases the accuracy of the results for energy values and transition strengths obtained so far, but also allows their calculation for <span class="hlt">magnetic</span> field strengths down to B≳BZ, where the adiabatic approximation fails. Restrictions: Intense <span class="hlt">magnetic</span> field strengths are required, since the expansion of the transverse single-particle wave functions using 8 Landau levels will no longer produce accurate results if the scaled <span class="hlt">magnetic</span> field strength parameter βZ=B/BZ becomes much smaller than unity. Unusual features: A huge program speed-up is achieved by making use of pre-calculated binary files. These can be calculated with additional programs provided with this package. Running time: 1-30 min.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JMMM..381..138M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JMMM..381..138M"><span id="translatedtitle">Preparation of modified <span class="hlt">magnetic</span> nanoparticles as a sorbent for the preconcentration and determination of cadmium ions in food and environmental water samples prior to flame <span class="hlt">atomic</span> absorption spectrometry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mirabi, Ali; Dalirandeh, Zeinab; Rad, Ali Shokuhi</p> <p>2015-05-01</p> <p>A new method has been developed for the separation/preconcentration of trace level cadmium ions using diphenyl carbazone/sodium dodecyl sulfate immobilized on <span class="hlt">magnetic</span> nanoparticle Fe3O4 as a new sorbent SPE and their determination by flame <span class="hlt">atomic</span> absorption spectrometry (FAAS). Synthesized nanoparticle was characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM). Various influencing parameters on the separation and preconcentration of trace level cadmium ions such as, pH value, amount of nanoparticles, amount of diphenyl carbazone, condition of eluting solution, the effects of matrix ions were examined. The cadmium ions can be eluted from the modified <span class="hlt">magnetic</span> nanoparticle using 1 mol L-1 HCl as a desorption reagent. The detection limit of this method for cadmium was 3.71 ng ml-1 and the R.S.D. was 0.503% (n=6). The advantages of this new method include rapidity, easy preparation of sorbents and a high concentration factor. The proposed method has been applied to the determination of Cd ions at trace levels in real samples such as, green tea, rice, tobacco, carrot, lettuce, ginseng, spice, tap water, river water, sea water with satisfactory results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JAP...118w3904H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JAP...118w3904H"><span id="translatedtitle">Experimental investigation of inhomogeneities, nanoscopic phase separation, and <span class="hlt">magnetism</span> in arc melted Fe-Cu metals with equal <span class="hlt">atomic</span> ratio of the constituents</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hassnain Jaffari, G.; Aftab, M.; Anjum, D. H.; Cha, Dongkyu; Poirier, Gerald; Ismat Shah, S.</p> <p>2015-12-01</p> <p>Composition gradient and phase separation at the nanoscale have been investigated for arc-melted and solidified with equiatomic Fe-Cu. Diffraction studies revealed that Fe and Cu exhibited phase separation with no trace of any mixing. Microscopy studies revealed that immiscible Fe-Cu form dense bulk nanocomposite. The spatial distribution of Fe and Cu showed existence of two distinct regions, i.e., Fe-rich and Cu-rich regions. Fe-rich regions have Cu precipitates of various sizes and different shapes, with Fe forming meshes or channels greater than 100 nm in size. On the other hand, the matrix of Cu-rich regions formed strips with fine strands of nanosized Fe. Macromagnetic response of the system showed ferromagnetic behavior with a <span class="hlt">magnetic</span> moment being equal to about 2.13 ?B/ Fe <span class="hlt">atom</span> and a bulk like negligible value of coercivity over the temperature range of 5-300 K. Anisotropy constant has been calculated from various laws of approach to saturation, and its value is extracted to be equal to 1350 J/m3. Inhomogeneous strain within the Cu and Fe crystallites has been calculated for the (unannealed) sample solidified after arc-melting. Annealed sample also exhibited local inhomogeneity with removal of inhomogeneous strain and no appreciable change in <span class="hlt">magnetic</span> character. However, for the annealed sample phase separated Fe exhibited homogenous strain.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22200313','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22200313"><span id="translatedtitle">Extraction and preconcentration of trace levels of cobalt using functionalized <span class="hlt">magnetic</span> nanoparticles in a sequential injection lab-on-valve system with detection by electrothermal <span class="hlt">atomic</span> absorption spectrometry.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Yang; Luo, Xiaoyu; Tang, Jie; Hu, Xiaoya; Xu, Qin; Yang, Chun</p> <p>2012-02-01</p> <p>A new approach to performing extraction and preconcentration employing functionalized <span class="hlt">magnetic</span> nanoparticles for the determination of trace metals is presented. Alumina-coated iron oxide nanoparticles were synthesized and used as the solid support. The nanoparticles were functionalized with sodium dodecyl sulfate and used as adsorbents for solid phase extraction of the analyte. Extraction, elution, and detection procedures were performed sequentially in the sequential injection lab-on-valve (SI-LOV) system followed by electrothermal <span class="hlt">atomic</span> absorption spectrometry (ETAAS). Mixtures of hydrophobic analytes were successfully extracted from solution using the synthesized <span class="hlt">magnetic</span> adsorbents. The potential use of the established scheme was demonstrated by taking cobalt as a model analyte. Under the optimal conditions, the calibration curve showed an excellent linearity in the concentration range of 0.01-5 μg L(-1), and the relative standard deviation was 2.8% at the 0.5 μg L(-1) level (n=11). The limit of detection was 6 ng L(-1) with a sampling frequency of 18 h(-1). The present method has been successfully applied to cobalt determination in water samples and two certified reference materials. PMID:22200313</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25442538','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25442538"><span id="translatedtitle"><span class="hlt">Magnetic</span> stirrer induced dispersive ionic-liquid microextraction for the determination of vanadium in water and food samples prior to graphite furnace <span class="hlt">atomic</span> absorption spectrometry.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Naeemullah; Kazi, Tasneem Gul; Tuzen, Mustafa</p> <p>2015-04-01</p> <p>A new dispersive liquid-liquid microextraction, <span class="hlt">magnetic</span> stirrer induced dispersive ionic-liquid microextraction (MS-IL-DLLME) was developed to quantify the trace level of vanadium in real water and food samples by graphite furnace <span class="hlt">atomic</span> absorption spectrometry (GFAAS). In this extraction method <span class="hlt">magnetic</span> stirrer was applied to obtained a dispersive medium of 1-butyl-3-methylimidazolium hexafluorophosphate [C4MIM][PF6] in aqueous solution of (real water samples and digested food samples) to increase phase transfer ratio, which significantly enhance the recovery of vanadium - 4-(2-pyridylazo) resorcinol (PAR) chelate. Variables having vital role on desired microextraction methods were optimised to obtain the maximum recovery of study analyte. Under the optimised experimental variables, enhancement factor (EF) and limit of detection (LOD) were achieved to be 125 and 18 ng L(-1), respectively. Validity and accuracy of the desired method was checked by analysis of certified reference materials (SLRS-4 Riverine water and NIST SRM 1515 Apple leaves). The relative standard deviation (RSD) for 10 replicate determinations at 0.5 ?g L(-1) of vanadium level was found to be <5.0%. This method was successfully applied to real water and acid digested food samples. PMID:25442538</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6823689','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6823689"><span id="translatedtitle">Global <span class="hlt">warming</span> - A reduced threat</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Michaels, P.J.; Stooksbury, D.E. )</p> <p>1992-10-01</p> <p>Issues associated with global <span class="hlt">warming</span> are analyzed focusing on global and hemispheric temperature histories and trace gas concentrations; artificial <span class="hlt">warming</span> from urban heat islands; high-latitude and diurnal temperatures; recent climate models; direct effects on vegetation of an increase in carbon dioxide; and compensatory cooling from other industrial products. Data obtained indicate that anthropogenerated sulfate emissions are mitigating some of the <span class="hlt">warming</span>, and that increased cloudiness as a result of these emissions will further enhance night, rather than day, <span class="hlt">warming</span>. It is noted that the sulfate emissions are not sufficient to explain all of the night <span class="hlt">warming</span>. The sensitivity of climate to anthropogenerated aerosols, and the general lack of previously predicted <span class="hlt">warming</span>, could drastically alter the debate on global <span class="hlt">warming</span> in favor of less expensive policies. 61 refs.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26953358','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26953358"><span id="translatedtitle">A sensitive <span class="hlt">magnetic</span> nanoparticle-based immunoassay of phosphorylated acetylcholinesterase using protein cage templated lead phosphate for signal amplification with graphite furnace <span class="hlt">atomic</span> absorption spectrometry detection.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liang, Pei; Kang, Caiyan; Yang, Enjian; Ge, Xiaoxiao; Du, Dan; Lin, Yuehe</p> <p>2016-03-21</p> <p>We developed a new <span class="hlt">magnetic</span> nanoparticle sandwich-like immunoassay using protein cage nanoparticles (PCN) for signal amplification together with graphite furnace <span class="hlt">atomic</span> absorption spectrometry (GFAAS) for the quantification of an organophosphorylated acetylcholinesterase adduct (OP-AChE), the biomarker of exposure to organophosphate pesticides (OPs) and nerve agents. OP-AChE adducts were firstly captured by titanium dioxide coated <span class="hlt">magnetic</span> nanoparticles (TiO2-MNPs) from the sample matrixes through metal chelation with phospho-moieties, and then selectively recognized by anti-AChE antibody labeled on PCN which was packed with lead phosphate in its cavity (PCN-anti-AChE). The sandwich-like immunoreaction was performed among TiO2-MNPs, OP-AChE and PCN-anti-AChE to form a TiO2-MNP/OP-AChE/PCN-anti-AChE immunocomplex. The complex could be easily isolated from the sample solution with the help of <span class="hlt">magnet</span>, and the released lead ions from PCN were detected by GFAAS for the quantification of OP-AChE. Greatly enhanced sensitivity was achieved because PCN increased the amount of metal ions in the cavity of each apoferritin. The proposed immunoassay yielded a linear response over a broad range of OP-AChE concentrations from 0.01 nM to 2 nM, with a detection limit of 2 pM, which has enough sensitivity for monitoring of low-dose exposure to OPs. This new method showed an acceptable stability and reproducibility and was validated with OP-AChE spiked human plasma. PMID:26953358</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26343434','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26343434"><span id="translatedtitle">In situ emulsification microextraction using a dicationic ionic liquid followed by <span class="hlt">magnetic</span> assisted physisorption for determination of lead prior to micro-sampling flame <span class="hlt">atomic</span> absorption spectrometry.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shokri, Masood; Beiraghi, Asadollah; Seidi, Shahram</p> <p>2015-08-19</p> <p>For the first time, a simple and efficient in situ emulsification microextraction method using a dicationic ionic liquid followed by <span class="hlt">magnetic</span> assisted physisorption was presented to determine trace amounts of lead. In this method, 400 μL of 1.0 mol L(-1) lithium bis (trifluoromethylsulfonyl) imide aqueous solution, Li[NTf2], was added into the sample solution containing 100 μL of 1.0 mol L(-1) 1,3-(propyl-1,3-diyl) bis (3-methylimidazolium) chloride, [pbmim]Cl2, to form a water immiscible ionic liquid, [pbmim][NTf2]2. This new in situ formed dicationic ionic liquid was applied as the acceptor phase to extract the lead-ammonium pyrrolidinedithiocarbamate (Pb-APDC) complexes from the sample solution. Subsequently, 30 mg of Fe3O4 <span class="hlt">magnetic</span> nanoparticles (MNPs) were added into the sample solution to collect the fine droplets of [pbmim][NTf2]2, physisorptively. Finally, MNPs were eluted by acetonitrile, separated by an external <span class="hlt">magnetic</span> field and the obtained eluent was subjected to micro-sampling flame <span class="hlt">atomic</span> absorption spectrometry (FAAS) for further analysis. Comparing with other microextraction methods, no special devices and centrifugation step are required. Parameters influencing the extraction efficiency such as extraction time, pH, concentration of chelating agent, amount of MNPs and coexisting interferences were studied. Under the optimized conditions, this method showed high extraction recovery of 93% with low LOD of 0.7 μg L(-1). Good linearity was obtained in the range of 2.5-150 μg L(-1) with determination coefficient (r(2)) of 0.9921. Relative standard deviation (RSD%) for seven repeated measurements at the concentration of 10 μg L(-1) was 4.1%. Finally, this method was successfully applied for determination of lead in some water and plant samples. PMID:26343434</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014RScI...85j3705K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014RScI...85j3705K"><span id="translatedtitle">Design of a self-aligned, wide temperature range (300 mK-300 K) <span class="hlt">atomic</span> force microscope/<span class="hlt">magnetic</span> force microscope with 10 nm <span class="hlt">magnetic</span> force microscope resolution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karcı, Özgür; Dede, Münir; Oral, Ahmet</p> <p>2014-10-01</p> <p>We describe the design of a wide temperature range (300 mK-300 K) <span class="hlt">atomic</span> force microscope/<span class="hlt">magnetic</span> force microscope with a self-aligned fibre-cantilever mechanism. An alignment chip with alignment groves and a special mechanical design are used to eliminate tedious and time consuming fibre-cantilever alignment procedure for the entire temperature range. A low noise, Michelson fibre interferometer was integrated into the system for measuring deflection of the cantilever. The spectral noise density of the system was measured to be ˜12 fm/√Hz at 4.2 K at 3 mW incident optical power. Abrikosov vortices in BSCCO(2212) single crystal sample and a high density hard disk sample were imaged at 10 nm resolution to demonstrate the performance of the system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22306223','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22306223"><span id="translatedtitle">Design of a self-aligned, wide temperature range (300 mK-300 K) <span class="hlt">atomic</span> force microscope/<span class="hlt">magnetic</span> force microscope with 10 nm <span class="hlt">magnetic</span> force microscope resolution</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Karcı, Özgür; Dede, Münir</p> <p>2014-10-01</p> <p>We describe the design of a wide temperature range (300 mK-300 K) <span class="hlt">atomic</span> force microscope/<span class="hlt">magnetic</span> force microscope with a self-aligned fibre-cantilever mechanism. An alignment chip with alignment groves and a special mechanical design are used to eliminate tedious and time consuming fibre-cantilever alignment procedure for the entire temperature range. A low noise, Michelson fibre interferometer was integrated into the system for measuring deflection of the cantilever. The spectral noise density of the system was measured to be ~12 fm/√Hz at 4.2 K at 3 mW incident optical power. Abrikosov vortices in BSCCO(2212) single crystal sample and a high density hard disk sample were imaged at 10 nm resolution to demonstrate the performance of the system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26172807','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26172807"><span id="translatedtitle">Ionization rate coefficients in <span class="hlt">warm</span> dense plasmas.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Aslanyan, V; Tallents, G J</p> <p>2015-06-01</p> <p>We recast the <span class="hlt">atomic</span> processes in a <span class="hlt">warm</span>, dense plasma using Fermi-Dirac statistics and compare them to the rates of the usual Maxwell-Boltzmann approach of many collisional-radiative models. Population calculations show insignificant differences to calculations assuming nondegenerate free electrons of plasmas at solid density close to local thermodynamic equilibrium, but show departures in average ionization in the presence of strong photoionization. For example, we show that electron degeneracy affects the evolution of plasmas created by ultraviolet free electron laser interaction with solid targets. PMID:26172807</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5317497','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5317497"><span id="translatedtitle">Global warning, global <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Benarde, M.A. )</p> <p>1992-01-01</p> <p>This book provides insights into the formidable array of issues which, in a warmer world, could impinge upon every facet of readers lives. It examines climatic change and long-term implications of global <span class="hlt">warming</span> for the ecosystem. Topics include the ozone layer and how it works; the greenhouse effect; the dangers of imbalance and its effects on human and animal life; disruptions to the basic ecology of the planet; and the real scientific evidence for and against aberrant climatic shifts. The author also examines workable social and political programs and changes that must be instituted to avoid ecological disaster.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22277826','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22277826"><span id="translatedtitle">Natural <span class="hlt">warm</span> inflation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Visinelli, Luca</p> <p>2011-09-01</p> <p>We derive the requirements that a generic axion-like field has to satisfy in order to play the role of the inflaton field in the <span class="hlt">warm</span> inflation scenario. Compared to the parameter space in ordinary Natural Inflation models, we find that the parameter space in our model is enlarged. In particular, we avoid the problem of having an axion decay constant f that relates to the Planck scale, which is instead present in the ordinary Natural Inflation models; in fact, our model can easily accommodate values of the axion decay constant that lie well below the Planck scale.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMGC22A..06S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMGC22A..06S"><span id="translatedtitle">Is Global <span class="hlt">Warming</span> Accelerating?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shukla, J.; Delsole, T. M.; Tippett, M. K.</p> <p>2009-12-01</p> <p>A global pattern that fluctuates naturally on decadal time scales is identified in climate simulations and observations. This newly discovered component, called the Global Multidecadal Oscillation (GMO), is related to the Atlantic Meridional Oscillation and shown to account for a substantial fraction of decadal fluctuations in the observed global average sea surface temperature. IPCC-class climate models generally underestimate the variance of the GMO, and hence underestimate the decadal fluctuations due to this component of natural variability. Decomposing observed sea surface temperature into a component due to anthropogenic and natural radiative forcing plus the GMO, reveals that most multidecadal fluctuations in the observed global average sea surface temperature can be accounted for by these two components alone. The fact that the GMO varies naturally on multidecadal time scales implies that it can be predicted with some skill on decadal time scales, which provides a scientific rationale for decadal predictions. Furthermore, the GMO is shown to account for about half of the <span class="hlt">warming</span> in the last 25 years and hence a substantial fraction of the recent acceleration in the rate of increase in global average sea surface temperature. Nevertheless, in terms of the global average “well-observed” sea surface temperature, the GMO can account for only about 0.1° C in transient, decadal-scale fluctuations, not the century-long 1° C <span class="hlt">warming</span> that has been observed during the twentieth century.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22408224','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22408224"><span id="translatedtitle"><span class="hlt">Magnetic</span> dipolar and quadrupolar transitions in two-electron <span class="hlt">atoms</span> under exponential-cosine-screened Coulomb potential</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Modesto-Costa, Lucas; Canuto, Sylvio; Mukherjee, Prasanta K.</p> <p>2015-03-15</p> <p>A detailed investigation of the <span class="hlt">magnetic</span> dipolar and quadrupolar excitation energies and transition probabilities of helium isoelectronic He, Be{sup 2+}, C{sup 4+}, and O{sup 6+} have been performed under exponential cosine screened Coulomb potential generated in a plasma environment. The low-lying excited states 1s{sup 2}:{sup 1}S{sup e} → 1sns:{sup 3}S{sup e}{sub 0}, and 1snp:{sup 3}P{sup o}{sub 2} (n = 2, 3, 4, and 5) are considered. The variational time-dependent coupled Hartree-Fock scheme has been used. The effect of the confinement produced by the potential on the structural properties is investigated for increasing coupling strength of the plasma. It is noted that there is a gradual destabilization of the energy of the system with the reduction of the ionization potential and the number of excited states. The effect of the screening enhancement on the excitation energies and transition probabilities has also been investigated and the results compared with those available for the free systems and under the simple screened Coulomb potential.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/603637','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/603637"><span id="translatedtitle">Advanced photoelectron spectrometer/diffractometer for studies of the <span class="hlt">atomic</span>, electronic, and <span class="hlt">magnetic</span> structure of surfaces, interfaces, and nanostructures</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ynzunza, R. X.; Tober, E. D.; Wang, Z.; Palomares, F. J.; Morais, J.; Denecke, R.; Ryce, S.; Zaninovich, J.; Westphal, C.; Miner, C. E.; Kay, A.; Leech, D.; Mellon, M.; Shaw, k.; Lind, D. M.; Liesegang, J.; Hussain, Z.; Smith, N. V.; Shirley, D. A.; Fadley, C. S.</p> <p>1997-04-01</p> <p>A next-generation experimental end station for surface and interface science studies has been developed with the aim of making full utilization of the capabilities of a third generation synchrotron radiation facility such as the Advanced Light Source. This system, the Advanced Photoelectron Spectrometer/Diffractrometer (APSD), has initially been installed on one half of the rotating platform on the bending <span class="hlt">magnet</span> beamline 9.3.2 and is planned to be moved to the Elliptical Polarized Undulator (EPU) beamline 4.0.1 in the latter part of 1997. The first phase of the APSD system is completely commissioned and it has been routinely used by both the PRT and independent investigators since November, 1994, for numerous studies, as discussed in a number of other reports in this compendium. The following is a brief description of the important characteristics of this experimental end station as it now stands, together with the various improvements and additions for enhancing its capabilities that are either underway or planned.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1080440','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1080440"><span id="translatedtitle">Method of performing MRI with an <span class="hlt">atomic</span> magnetometer</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Savukov, Igor Mykhaylovich; Matlashov, Andrei Nikolaevich; Espy, Michelle A.; Volegov, Petr Lvovich; Kraus, Jr., Robert Henry; Zotev, Vadim Sergeyevich</p> <p>2012-11-06</p> <p>A method and apparatus are provided for performing an in-situ <span class="hlt">magnetic</span> resonance imaging of an object. The method includes the steps of providing an <span class="hlt">atomic</span> magnetometer, coupling a <span class="hlt">magnetic</span> field generated by <span class="hlt">magnetically</span> resonating samples of the object through a flux transformer to the <span class="hlt">atomic</span> magnetometer and measuring a <span class="hlt">magnetic</span> resonance of the <span class="hlt">atomic</span> magnetometer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1093274','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1093274"><span id="translatedtitle">Method of performing MRI with an <span class="hlt">atomic</span> magnetometer</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Savukov, Igor Mykhaylovich; Matlashov, Andrei Nikolaevich; Espy, Michelle A; Volegov, Petr Lvovich; Kraus, Jr., Robert Henry; Zotev, Vadim Sergeyevich</p> <p>2013-08-27</p> <p>A method and apparatus are provided for performing an in-situ <span class="hlt">magnetic</span> resonance imaging of an object. The method includes the steps of providing an <span class="hlt">atomic</span> magnetometer, coupling a <span class="hlt">magnetic</span> field generated by <span class="hlt">magnetically</span> resonating samples of the object through a flux transformer to the <span class="hlt">atomic</span> magnetometer and measuring a <span class="hlt">magnetic</span> resonance of the <span class="hlt">atomic</span> magnetometer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19990018501','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19990018501"><span id="translatedtitle">Global <span class="hlt">Warming</span> on Triton</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Elliot, J. L.; Hammel, H. B.; Wasserman, L. H.; Franz, O. G.; McDonald, S. W.; Person, M. J.; Olkin, C. B.; Dunham, E. J.; Spencer, J. R.; Stansberry, J. A.; Buie, M. W.; Pasachoff, J. M.; Babcock, B. A.; McConnochie, T. H.</p> <p>1998-01-01</p> <p>Triton, Neptune's largest moon, has been predicted to undergo significant seasonal changes that would reveal themselves as changes in its mean frost temperature. But whether this temperature should at the present time be increasing, decreasing or constant depends on a number of parameters (such as the thermal properties of the surface, and frost migration patterns) that are unknown. Here we report observations of a recent stellar occultation by Triton which, when combined with earlier results, show that Triton has undergone a period of global <span class="hlt">warming</span> since 1989. Our most conservative estimates of the rate of temperature and surface-pressure increase during this period imply that the atmosphere is doubling in bulk every 10 years, significantly faster than predicted by any published frost model for Triton. Our result suggests that permanent polar caps on Triton play a c dominant role in regulating seasonal atmospheric changes. Similar processes should also be active on Pluto.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5930382','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5930382"><span id="translatedtitle"><span class="hlt">Warm</span> waters, bleached corals</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Roberts, L.</p> <p>1990-10-12</p> <p>Two researchers, Tom Goreau of the Discovery Laboratory in Jamaica and Raymond Hayes of Howard University, claim that they have evidence that nearly clinches the temperature connection to the bleached corals in the Caribbean and that the coral bleaching is an indication of Greenhouse <span class="hlt">warming</span>. The incidents of scattered bleaching of corals, which have been reported for decades, are increasing in both intensity and frequency. The researchers based their theory on increased temperature of the seas measured by satellites. However, some other scientists feel that the satellites measure the temperature of only the top few millimeters of the water and that since corals lie on reefs perhaps 60 to 100 feet below the ocean surface, the elevated temperatures are not significant.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6710038','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6710038"><span id="translatedtitle">Global <span class="hlt">warming</span> challenge</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hengeveld, H. )</p> <p>1994-11-01</p> <p>Global <span class="hlt">warming</span> will necessitate significant adjustments in Canadian society and its economy. In 1979, the Canadian federal government created its Canadian Climate Program (CCP) in collaboration with other agencies, institutions, and individuals. It sought to coordinate national efforts to understand global and regional climate, and to promote better use of the emerging knowledge. Much of the CCP-coordinated research into sources and sinks of greenhouse gases interfaces with other national and international programs. Other researchers have become involved in the Northern Wetlands Study, a cooperative United States-Canada initiative to understand the role of huge northern bogs and muskegs in the carbon cycle. Because of the need to understand how the whole, linked climate system works, climate modeling emerged as a key focus of current research. 35 refs., 4 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22282887','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22282887"><span id="translatedtitle">Interacting <span class="hlt">warm</span> dark matter</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cruz, Norman; Palma, Guillermo; Zambrano, David; Avelino, Arturo E-mail: guillermo.palma@usach.cl E-mail: avelino@fisica.ugto.mx</p> <p>2013-05-01</p> <p>We explore a cosmological model composed by a dark matter fluid interacting with a dark energy fluid. The interaction term has the non-linear ??{sub m}{sup ?}?{sub e}{sup ?} form, where ?{sub m} and ?{sub e} are the energy densities of the dark matter and dark energy, respectively. The parameters ? and ? are in principle not constrained to take any particular values, and were estimated from observations. We perform an analytical study of the evolution equations, finding the fixed points and their stability properties in order to characterize suitable physical regions in the phase space of the dark matter and dark energy densities. The constants (?,?,?) as well as w{sub m} and w{sub e} of the EoS of dark matter and dark energy respectively, were estimated using the cosmological observations of the type Ia supernovae and the Hubble expansion rate H(z) data sets. We find that the best estimated values for the free parameters of the model correspond to a <span class="hlt">warm</span> dark matter interacting with a phantom dark energy component, with a well goodness-of-fit to data. However, using the Bayesian Information Criterion (BIC) we find that this model is overcame by a <span class="hlt">warm</span> dark matter phantom dark energy model without interaction, as well as by the ?CDM model. We find also a large dispersion on the best estimated values of the (?,?,?) parameters, so even if we are not able to set strong constraints on their values, given the goodness-of-fit to data of the model, we find that a large variety of theirs values are well compatible with the observational data used.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JCAP...05..034C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JCAP...05..034C"><span id="translatedtitle">Interacting <span class="hlt">warm</span> dark matter</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cruz, Norman; Palma, Guillermo; Zambrano, David; Avelino, Arturo</p> <p>2013-05-01</p> <p>We explore a cosmological model composed by a dark matter fluid interacting with a dark energy fluid. The interaction term has the non-linear ??m??e? form, where ?m and ?e are the energy densities of the dark matter and dark energy, respectively. The parameters ? and ? are in principle not constrained to take any particular values, and were estimated from observations. We perform an analytical study of the evolution equations, finding the fixed points and their stability properties in order to characterize suitable physical regions in the phase space of the dark matter and dark energy densities. The constants (?,?,?) as well as wm and we of the EoS of dark matter and dark energy respectively, were estimated using the cosmological observations of the type Ia supernovae and the Hubble expansion rate H(z) data sets. We find that the best estimated values for the free parameters of the model correspond to a <span class="hlt">warm</span> dark matter interacting with a phantom dark energy component, with a well goodness-of-fit to data. However, using the Bayesian Information Criterion (BIC) we find that this model is overcame by a <span class="hlt">warm</span> dark matter - phantom dark energy model without interaction, as well as by the ?CDM model. We find also a large dispersion on the best estimated values of the (?,?,?) parameters, so even if we are not able to set strong constraints on their values, given the goodness-of-fit to data of the model, we find that a large variety of theirs values are well compatible with the observational data used.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17688330','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17688330"><span id="translatedtitle">Linear-scaling method for calculating nuclear <span class="hlt">magnetic</span> resonance chemical shifts using gauge-including <span class="hlt">atomic</span> orbitals within Hartree-Fock and density-functional theory.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kussmann, Jrg; Ochsenfeld, Christian</p> <p>2007-08-01</p> <p>Details of a new density matrix-based formulation for calculating nuclear <span class="hlt">magnetic</span> resonance chemical shifts at both Hartree-Fock and density functional theory levels are presented. For systems with a nonvanishing highest occupied molecular orbital-lowest unoccupied molecular orbital gap, the method allows us to reduce the asymptotic scaling order of the computational effort from cubic to linear, so that molecular systems with 1000 and more <span class="hlt">atoms</span> can be tackled with today's computers. The key feature is a reformulation of the coupled-perturbed self-consistent field (CPSCF) theory in terms of the one-particle density matrix (D-CPSCF), which avoids entirely the use of canonical MOs. By means of a direct solution for the required perturbed density matrices and the adaptation of linear-scaling integral contraction schemes, the overall scaling of the computational effort is reduced to linear. A particular focus of our formulation is to ensure numerical stability when sparse-algebra routines are used to obtain an overall linear-scaling behavior. PMID:17688330</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012APS..MAR.X1014K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012APS..MAR.X1014K"><span id="translatedtitle">Design of a Self-Aligned, High Sensitivity Fiber Fabry-Perot Interferometer for Low Temperature <span class="hlt">Atomic</span> Force Microscope/<span class="hlt">Magnetic</span> Force Microscope</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karci, Ozgur; Dede, Munir; Oral, Ahmet</p> <p>2012-02-01</p> <p>We describe the design of a high sensitivity fiber Fabry-Perot interferometer for low temperature <span class="hlt">atomic</span> force microscope/<span class="hlt">magnetic</span> force microscope. This is a self-aligned system utilizing an alignment chip and eliminating all tedious alignment procedures. Our interferometer cavity is composed of a cleaved fiber, which is coated using dielectric to increase the reflectivity of laser from fiber-air interface, and a cantilever. 50 percent of the incident laser beam is reflected at the end of the fiber. The transmitted light propagates from the fiber end and hits the cantilever. Multiple reflections occur between cantilever and the fiber then the beams go into the fiber again. These two beams interfere and generate a photocurrent at the PD which is used for deflection measurement. We designed a special stick-slip coarse approach mechanism using piezoelectric tube scanner of the microscope. We have measured 8fm per square root Hz noise level at 300K, while the shot noise limit was 2fm per square root Hz. Our previous Michelson interferometer design had 20 fm per square root Hz noise level and gave better than 10nm MFM resolution on hard disk. Our goal is to further enhance the noise levels and achieve 6 nm resolution for LT-MFM with this new interferometer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5371673','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5371673"><span id="translatedtitle">Laser-<span class="hlt">magnetic</span>-resonance detection of magnesium <span class="hlt">atoms</span> in the metastable /sup 3/P/sub 0,ts1,ts2/ states</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Inguscio, M.; Leopold, K.R.; Murray, J.S.; Evenson, K.M.</p> <p>1985-09-01</p> <p>Transitions between fine-structure levels of the metastable (3s3p/sup 3/P) state of magnesium have been observed by means of the highly sensitive technique of far-infrared laser-<span class="hlt">magnetic</span>-resonance spectroscopy. The g factors for the /sup 3/P/sub 1/ and /sup 3/P/sub 2/ levels are 1.50111(16) and 1.50102(16), respectively, and the /sup 3/P/sub 1/--/sup 3/P/sub 2/ energy separation is1 220575.1(33) MHz. The observed g factors show good agreement with the predicted values. This stands in marked contrast to similar results for <span class="hlt">atomic</span> silicon (/sup 3/P) and aluminum (/sup 2/P), for which the theoretical and experimental g factors differ substantially. The value of the /sup 3/P/sub 1/--/sup 3/P/sub 2/ energy separation is improved by nearly 2 orders of magnitude over the optical value and is of sufficient accuracy to permit possible extraterrestrial identification.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010SPIE.7586E..0LT','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010SPIE.7586E..0LT"><span id="translatedtitle">Nuclear spin polarization of 3He <span class="hlt">atoms</span> with a frequency doubled Ti:sapphire laser toward nuclear <span class="hlt">magnetic</span> resonance of porous media</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tabata, Y.; Yamada, H.; Maeda, S.; Morioka, H.; Kumagai, H.; Kobayashi, A.</p> <p>2010-02-01</p> <p>NMR based on laser-polarized 3He gases has been attracted as a powerful tool for characterizing physical parameters of porous media and then imaging human lungs. In this paper, the feasibility study of nuclear polarization of 3He <span class="hlt">atoms</span> utilizing the 23S-33P transition at 389 nm is reported in comparison with the conventional 23S-23P transition at 1083 nm. The 389-nm light has been available readily with the development of various indium gallium nitride light-emitting diodes (InGaN LEDs). In this work, the frequency-doubled light of a 778-nm CW Ti:sapphire laser with the nonlinear crystal (BiB3O6) was used as the optical pumping light at 389 nm. The other light from a Littrow external cavity diode laser was also used for optical pumping at the 1083-nm wavelength and then measurement of the nuclear polarization. The nuclear polarization of 1.8% with optical pumping at the 23S-33P transition was demonstrated and then it was found that the (23S1, F=1/2)-(33P0, F=1/2) transition was the most efficient transition of 23S-33P lines for the <span class="hlt">magnetic</span> field of 1.6 mT and the gas pressure of 0.5 Torr.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5894526','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5894526"><span id="translatedtitle">Global <span class="hlt">warming</span> and prairie wetlands</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Poiani, K.A. ); Johnson, W.C. )</p> <p>1991-10-01</p> <p>In this article, the authors discuss current understanding and projections of global <span class="hlt">warming</span>; review wetland vegetation dynamics to establish the strong relationship among climate, wetland hydrology, vegetation patterns and waterfowl habitat; discuss the potential effects of a greenhouse <span class="hlt">warming</span> on these relationships; and illustrate the potential effects of climate change on wetland habitat by using a simulation model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008CoPhC.178..301C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008CoPhC.178..301C"><span id="translatedtitle">POTHMF: A program for computing potential curves and matrix elements of the coupled adiabatic radial equations for a hydrogen-like <span class="hlt">atom</span> in a homogeneous <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chuluunbaatar, O.; Gusev, A. A.; Gerdt, V. P.; Rostovtsev, V. A.; Vinitsky, S. I.; Abrashkevich, A. G.; Kaschiev, M. S.; Serov, V. V.</p> <p>2008-02-01</p> <p>A FORTRAN 77 program is presented which calculates with the relative machine precision potential curves and matrix elements of the coupled adiabatic radial equations for a hydrogen-like <span class="hlt">atom</span> in a homogeneous <span class="hlt">magnetic</span> field. The potential curves are eigenvalues corresponding to the angular oblate spheroidal functions that compose adiabatic basis which depends on the radial variable as a parameter. The matrix elements of radial coupling are integrals in angular variables of the following two types: product of angular functions and the first derivative of angular functions in parameter, and product of the first derivatives of angular functions in parameter, respectively. The program calculates also the angular part of the dipole transition matrix elements (in the length form) expressed as integrals in angular variables involving product of a dipole operator and angular functions. Moreover, the program calculates asymptotic regular and irregular matrix solutions of the coupled adiabatic radial equations at the end of interval in radial variable needed for solving a multi-channel scattering problem by the generalized R-matrix method. Potential curves and radial matrix elements computed by the POTHMF program can be used for solving the bound state and multi-channel scattering problems. As a test desk, the program is applied to the calculation of the energy values, a short-range reaction matrix and corresponding wave functions with the help of the KANTBP program. Benchmark calculations for the known photoionization cross-sections are presented. Program summaryProgram title:POTHMF Catalogue identifier:AEAA_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEAA_v1_0.html Program obtainable from:CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions:Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.:8123 No. of bytes in distributed program, including test data, etc.:131 396 Distribution format:tar.gz Programming language:FORTRAN 77 Computer:Intel Xeon EM64T, Alpha 21264A, AMD Athlon MP, Pentium IV Xeon, Opteron 248, Intel Pentium IV Operating system:OC Linux, Unix AIX 5.3, SunOS 5.8, Solaris, Windows XP RAM:Depends on the number of radial differential equations; the number and order of finite elements; the number of radial points. Test run requires 4 MB Classification:2.5 External routines:POTHMF uses some Lapack routines, copies of which are included in the distribution (see README file for details). Nature of problem:In the multi-channel adiabatic approach the Schrdinger equation for a hydrogen-like <span class="hlt">atom</span> in a homogeneous <span class="hlt">magnetic</span> field of strength ? ( ?=B/B, B?2.3510 T is a dimensionless parameter which determines the field strength B) is reduced by separating the radial coordinate, r, from the angular variables, (?,?), and using a basis of the angular oblate spheroidal functions [3] to a system of second-order ordinary differential equations which contain first-derivative coupling terms [4]. The purpose of this program is to calculate potential curves and matrix elements of radial coupling needed for calculating the low-lying bound and scattering states of hydrogen-like <span class="hlt">atoms</span> in a homogeneous <span class="hlt">magnetic</span> field of strength 0<??1000 within the adiabatic approach [5]. The program evaluates also asymptotic regular and irregular matrix radial solutions of the multi-channel scattering problem needed to extract from the R-matrix a required symmetric shortrange open-channel reaction matrix K [6] independent from matching point [7]. In addition, the program computes the dipole transition matrix elements in the length form between the basis functions that are needed for calculating the dipole transitions between the low-lying bound and scattering states and photoionization cross sections [8]. Solution method:The angular oblate spheroidal eigenvalue problem depending on the radial variable is solved using a series expansion in the Legendre polynomials [3]. The resulting tridiagonal symmetric algebraic eigenvalue problem for the evaluation of selected eigenvalues, i.e. the potential curves, is solved by the LDLT factorization using the DSTEVR program [2]. Derivatives of the eigenfunctions with respect to the radial variable which are contained in matrix elements of the coupled radial equations are obtained by solving the inhomogeneous algebraic equations. The corresponding algebraic problem is solved by using the LDLT factorization with the help of the DPTTRS program [2]. Asymptotics of the matrix elements at large values of radial variable are computed using a series expansion in the associated Laguerre polynomials [9]. The corresponding matching points between the numeric and asymptotic solutions are found automatically. These asymptotics are used for the evaluation of the asymptotic regular and irregular matrix radial solutions of the multi-channel scattering problem [7]. As a test desk, the program is applied to the calculation of the energy values of the ground and excited bound states and reaction matrix of multi-channel scattering problem for a hydrogen <span class="hlt">atom</span> in a homogeneous <span class="hlt">magnetic</span> field using the KANTBP program [10]. Restrictions:The computer memory requirements depend on: the number of radial differential equations; the number and order of finite elements; the total number of radial points. Restrictions due to dimension sizes can be changed by resetting a small number of PARAMETER statements before recompiling (see Introduction and listing for details). Running time:The running time depends critically upon: the number of radial differential equations; the number and order of finite elements; the total number of radial points on interval [r,r]. The test run which accompanies this paper took 7 s required for calculating of potential curves, radial matrix elements, and dipole transition matrix elements on a finite-element grid on interval [ r=0, r=100] used for solving discrete and continuous spectrum problems and obtaining asymptotic regular and irregular matrix radial solutions at r=100 for continuous spectrum problem on the Intel Pentium IV 2.4 GHz. The number of radial differential equations was equal to 6. The accompanying test run using the KANTBP program took 2 s for solving discrete and continuous spectrum problems using the above calculated potential curves, matrix elements and asymptotic regular and irregular matrix radial solutions. Note, that in the accompanied benchmark calculations of the photoionization cross-sections from the bound states of a hydrogen <span class="hlt">atom</span> in a homogeneous <span class="hlt">magnetic</span> field to continuum we have used interval [ r=0, r=1000] for continuous spectrum problem. The total number of radial differential equations was varied from 10 to 18. References:W.H. Press, S.A. Teukolsky, W.T. Vetterling, B.P. Flannery, Numerical Recipes: The Art of Scientific Computing, Cambridge University Press, Cambridge, 1986. http://www.netlib.org/lapack/. M. Abramovits, I.A. Stegun, Handbook of Mathematical Functions, Dover, New York, 1965. U. Fano, Colloq. Int. C.N.R.S. 273 (1977) 127; A.F. Starace, G.L. Webster, Phys. Rev. A 19 (1979) 1629-1640; C.V. Clark, K.T. Lu, A.F. Starace, in: H.G. Beyer, H. Kleinpoppen (Eds.), Progress in <span class="hlt">Atomic</span> Spectroscopy, Part C, Plenum, New York, 1984, pp. 247-320; U. Fano, A.R.P. Rau, <span class="hlt">Atomic</span> Collisions and Spectra, Academic Press, Florida, 1986. M.G. Dimova, M.S. Kaschiev, S.I. Vinitsky, J. Phys. B 38 (2005) 2337-2352; O. Chuluunbaatar, A.A. Gusev, V.L. Derbov, M.S. Kaschiev, V.V. Serov, T.V. Tupikova, S.I. Vinitsky, Proc. SPIE 6537 (2007) 653706-1-18. M.J. Seaton, Rep. Prog. Phys. 46 (1983) 167-257. M. Gailitis, J. Phys. B 9 (1976) 843-854; J. Macek, Phys. Rev. A 30 (1984) 1277-1278; S.I. Vinitsky, V.P. Gerdt, A.A. Gusev, M.S. Kaschiev, V.A. Rostovtsev, V.N. Samoylov, T.V. Tupikova, O. Chuluunbaatar, Programming and Computer Software 33 (2007) 105-116. H. Friedrich, Theoretical <span class="hlt">Atomic</span> Physics, Springer, New York, 1991. R.J. Damburg, R.Kh. Propin, J. Phys. B 1 (1968) 681-691; J.D. Power, Phil. Trans. Roy. Soc. London A 274 (1973) 663-702. O. Chuluunbaatar, A.A. Gusev, A.G. Abrashkevich, A. Amaya-Tapia, M.S. Kaschiev, S.Y. Larsen, S.I. Vinitsky, Comput. Phys. Comm. 177 (2007) 649-675.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22136614','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22136614"><span id="translatedtitle">A RELATION BETWEEN THE <span class="hlt">WARM</span> NEUTRAL AND IONIZED MEDIA OBSERVED IN THE CANADIAN GALACTIC PLANE SURVEY</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Foster, T.; Kothes, R.; Brown, J. C.</p> <p>2013-08-10</p> <p>We report on a comparison between 21 cm rotation measure (RM) and the optically thin <span class="hlt">atomic</span> hydrogen column density (N{sub H{sub I}}({tau} {yields} 0)) measured toward unresolved extragalactic sources in the Galactic plane of the northern sky. H I column densities integrated to the Galactic edge are measured immediately surrounding each of nearly 2000 sources in 1 arcmin 21 cm line data, and are compared to RMs observed from polarized emission of each source. RM data are binned in column density bins 4 Multiplication-Sign 10{sup 20} cm{sup -2} wide, and one observes a strong relationship between the number of hydrogen <span class="hlt">atoms</span> in a 1 cm{sup 2} column through the plane and the mean RM along the same line of sight and path length. The relationship is linear over one order of magnitude (from 0.8 to 14 Multiplication-Sign 10{sup 21} <span class="hlt">atoms</span> cm{sup -2}) of column densities, with a constant RM/N{sub H{sub I}}{approx} -23.2 {+-} 2.3 rad m{sup -2}/10{sup 21} <span class="hlt">atoms</span> cm{sup -2}, and a positive RM of 45.0 {+-} 13.8 rad m{sup -2} in the presence of no <span class="hlt">atomic</span> hydrogen. This slope is used to calculate a mean volume-averaged <span class="hlt">magnetic</span> field in the second quadrant of (B{sub Parallel-To }) {approx}1.0 {+-} 0.1 {mu}G directed away from the Sun, assuming an ionization fraction of 8% (consistent with the <span class="hlt">warm</span>-neutral medium; WNM). The remarkable consistency between this field and (B) = 1.2 {mu}G found with the same RM sources and a Galactic model of dispersion measures (DMs) suggests that electrons in the partially ionized WNM are mainly responsible for pulsar DMs, and thus the partially ionized WNM is the dominant form of the magneto-ionic interstellar medium.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ApJ...773L..11F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ApJ...773L..11F"><span id="translatedtitle">A Relation between the <span class="hlt">Warm</span> Neutral and Ionized Media Observed in the Canadian Galactic Plane Survey</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Foster, T.; Kothes, R.; Brown, J. C.</p> <p>2013-08-01</p> <p>We report on a comparison between 21 cm rotation measure (RM) and the optically thin <span class="hlt">atomic</span> hydrogen column density (N H I (? ? 0)) measured toward unresolved extragalactic sources in the Galactic plane of the northern sky. H I column densities integrated to the Galactic edge are measured immediately surrounding each of nearly 2000 sources in 1 arcmin 21 cm line data, and are compared to RMs observed from polarized emission of each source. RM data are binned in column density bins 4 1020 cm-2 wide, and one observes a strong relationship between the number of hydrogen <span class="hlt">atoms</span> in a 1 cm2 column through the plane and the mean RM along the same line of sight and path length. The relationship is linear over one order of magnitude (from 0.8 to 14 1021 <span class="hlt">atoms</span> cm-2) of column densities, with a constant RM/N H I ~ -23.2 2.3 rad m-2/1021 <span class="hlt">atoms</span> cm-2, and a positive RM of 45.0 13.8 rad m-2 in the presence of no <span class="hlt">atomic</span> hydrogen. This slope is used to calculate a mean volume-averaged <span class="hlt">magnetic</span> field in the second quadrant of langB ?rang ~1.0 0.1 ?G directed away from the Sun, assuming an ionization fraction of 8% (consistent with the <span class="hlt">warm</span>-neutral medium; WNM). The remarkable consistency between this field and langBrang = 1.2 ?G found with the same RM sources and a Galactic model of dispersion measures (DMs) suggests that electrons in the partially ionized WNM are mainly responsible for pulsar DMs, and thus the partially ionized WNM is the dominant form of the magneto-ionic interstellar medium.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22273827','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22273827"><span id="translatedtitle">Change in <span class="hlt">magnetic</span> and structural properties of FeRh thin films by gold cluster ion beam irradiation with the energy of 1.67 MeV/<span class="hlt">atom</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Koide, T.; Iwase, A.; Saitoh, Y.; Sakamaki, M.; Amemiya, K.; Matsui, T.</p> <p>2014-05-07</p> <p>The effect of energetic cluster ion beam irradiation on <span class="hlt">magnetic</span> and structural properties of FeRh thin films have been investigated. The cluster ions used in the present studies consist of a few gold <span class="hlt">atoms</span> with the energy of 1.67 MeV/gold <span class="hlt">atom</span>. Saturation <span class="hlt">magnetization</span> of the sample irradiated with Au3 cluster ion beam (280 emu/cc) is larger than that for the irradiated sample with Au1 ion beam (240 emu/cc) for the same irradiation ion fluence. These results can also be confirmed by the X-ray <span class="hlt">magnetic</span> circular dichroism (XMCD) measurement; the XMCD signal for Au3 cluster ion irradiation is larger than that for Au1 ion irradiation. Since the ion beam irradiation induced <span class="hlt">magnetization</span> of FeRh is significantly correlated with the amount of the lattice defects in the samples, cluster ion beam irradiation can be considered to effectively introduce the lattice defects in B2-type FeRh rather than the single ion beam. Consequently, cluster ion irradiation is better than single ion irradiation for the viewpoint of saturation <span class="hlt">magnetization</span>, even if the same irradiation energy is deposited in the samples.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.7794B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.7794B"><span id="translatedtitle">Defining Sudden Stratospheric <span class="hlt">Warmings</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Butler, Amy; Seidel, Dian; Hardiman, Steven; Butchart, Neal; Birner, Thomas; Match, Aaron</p> <p>2015-04-01</p> <p>The general form of the definition for Sudden Stratospheric <span class="hlt">Warmings</span> (SSWs) is largely agreed to be a reversal of the temperature gradient and of the zonal circulation polewards of 60 latitude at the 10 hPa level, as developed by the World Meteorological Organization (WMO) in the 1960s and 1970s. However, the details of the definition and its calculation are ambiguous, resulting in inconsistent classifications of SSW events. These discrepancies are problematic for understanding the observed frequency and statistical relationships with SSWs, and for maintaining a robust metric with which to assess wintertime stratospheric variability in observations and climate models. To provide a basis for community-wide discussion, we examine how the SSW definition has changed over time and how sensitive the detection of SSWs is to the definition used. We argue that the general form of the SSW definition should be clarified to ensure that it serves current research and forecasting purposes, and propose possible ways to update the definition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20080030145&hterms=hydro&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dhydro','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20080030145&hterms=hydro&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dhydro"><span id="translatedtitle">Explaining <span class="hlt">Warm</span> Coronal Loops</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Klimchuk, James A.; Karpen, Judy T.; Patsourakos, Spiros</p> <p>2008-01-01</p> <p>One of the great mysteries of coronal physics that has come to light in the last few years is the discovery that warn (- 1 INK) coronal loops are much denser than expected for quasi-static equilibrium. Both the excess densities and relatively long lifetimes of the loops can be explained with bundles of unresolved strands that are heated impulsively to very high temperatures. Since neighboring strands are at different stages of cooling, the composite loop bundle is multi-thermal, with the distribution of temperatures depending on the details of the "nanoflare storm." Emission hotter than 2 MK is predicted, but it is not clear that such emission is always observed. We consider two possible explanations for the existence of over-dense <span class="hlt">warm</span> loops without corresponding hot emission: (1) loops are bundles of nanoflare heated strands, but a significant fraction of the nanoflare energy takes the form of a nonthermal electron beam rather then direct plasma heating; (2) loops are bundles of strands that undergo thermal nonequilibrium that results when steady heating is sufficiently concentrated near the footpoints. We present numerical hydro simulations of both of these possibilities and explore the observational consequences, including the production of hard X-ray emission and absorption by cool material in the corona.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22282760','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22282760"><span id="translatedtitle"><span class="hlt">Warming</span> up for Planck</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bartrum, Sam; Berera, Arjun; Rosa, Joo G. E-mail: ab@ph.ed.ac.uk</p> <p>2013-06-01</p> <p>The recent Planck results and future releases on the horizon present a key opportunity to address a fundamental question in inflationary cosmology of whether primordial density perturbations have a quantum or thermal origin, i.e. whether particle production may have significant effects during inflation. <span class="hlt">Warm</span> inflation provides a natural arena to address this issue, with interactions between the scalar inflaton and other degrees of freedom leading to dissipative entropy production and associated thermal fluctuations. In this context, we present relations between CMB observables that can be directly tested against observational data. In particular, we show that the presence of a thermal bath warmer than the Hubble scale during inflation decreases the tensor-to-scalar ratio with respect to the conventional prediction in supercooled inflation, yielding r < 8|n{sub t}|, where n{sub t} is the tensor spectral index. Focusing on supersymmetric models at low temperatures, we determine consistency relations between the observables characterizing the spectrum of adiabatic scalar and tensor modes, both for generic potentials and particular canonical examples, and which we compare with the WMAP and Planck results. Finally, we include the possibility of producing the observed baryon asymmetry during inflation through dissipative effects, thereby generating baryon isocurvature modes that can be easily accommodated by the Planck data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20991195','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20991195"><span id="translatedtitle">Spatially resolved photoionization of ultracold <span class="hlt">atoms</span> on an <span class="hlt">atom</span> chip</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kraft, S.; Guenther, A.; Fortagh, J.; Zimmermann, C.</p> <p>2007-06-15</p> <p>We report on photoionization of ultracold <span class="hlt">magnetically</span> trapped Rb <span class="hlt">atoms</span> on an <span class="hlt">atom</span> chip. The <span class="hlt">atoms</span> are trapped at 5 {mu}K in a strongly anisotropic trap. Through a hole in the chip with a diameter of 150 {mu}m, two laser beams are focused onto a fraction of the <span class="hlt">atomic</span> cloud. A first laser beam with a wavelength of 778 nm excites the <span class="hlt">atoms</span> via a two-photon transition to the 5D level. With a fiber laser at 1080 nm the excited <span class="hlt">atoms</span> are photoionized. Ionization leads to depletion of the <span class="hlt">atomic</span> density distribution observed by absorption imaging. The resonant ionization spectrum is reported. The setup used in this experiment is suitable not only to investigate mixtures of Bose-Einstein condensates and ions but also for single-<span class="hlt">atom</span> detection on an <span class="hlt">atom</span> chip.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JAsGe...4..154A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JAsGe...4..154A"><span id="translatedtitle"><span class="hlt">Magnetic</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aboud, Essam; El-Masry, Nabil; Qaddah, Atef; Alqahtani, Faisal; Moufti, Mohammed R. H.</p> <p>2015-06-01</p> <p>The Rahat volcanic field represents one of the widely distributed Cenozoic volcanic fields across the western regions of the Arabian Peninsula. Its human significance stems from the fact that its northern fringes, where the historical eruption of 1256 A.D. took place, are very close to the holy city of Al-Madinah Al-Monawarah. In the present work, we analyzed aeromagnetic data from the northern part of Rahat volcanic field as well as carried out a ground gravity survey. A joint interpretation and inversion of gravity and <span class="hlt">magnetic</span> data were used to estimate the thickness of the lava flows, delineate the subsurface structures of the study area, and estimate the depth to basement using various geophysical methods, such as Tilt Derivative, Euler Deconvolution and 2D modeling inversion. Results indicated that the thickness of the lava flows in the study area ranges between 100 m (above Sea Level) at the eastern and western boundaries of Rahat Volcanic field and getting deeper at the middle as 300-500 m. It also showed that, major structural trend is in the NW direction (Red Sea trend) with some minor trends in EW direction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998JAP....83.7127E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998JAP....83.7127E"><span id="translatedtitle"><span class="hlt">Magnetization</span> processes in hybrid <span class="hlt">magnets</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Emura, M.; Neiva, A. C.; Missell, F. P.; Babcock, K. L.; Ormerod, J.; Constantinides, S.</p> <p>1998-06-01</p> <p>Injection-molded, oriented hybrid <span class="hlt">magnets</span> consisting of mixtures of BaO?6Fe2O3 and MQP-Q (exchange-coupled Nd2Fe14B+?-Fe) are compared to bonded <span class="hlt">magnets</span> made only from ferrite or MQP-Q. The <span class="hlt">magnetic</span> fractions of the hybrid <span class="hlt">magnets</span> consist of 80, 60, or 40 wt % ferrite blended with 20, 40, or 60 wt % MQP-Q. The microstructure was investigated by x-ray diffraction, scanning electron microscopy, <span class="hlt">atomic</span> force microscopy, and <span class="hlt">magnetic</span> force microscopy. <span class="hlt">Atomic</span> and <span class="hlt">magnetic</span> force microscopy images indicated differences between the physical and <span class="hlt">magnetic</span> microstructures. <span class="hlt">Magnetic</span> interactions were studied via isothermal remanence (IRM) and dc-demagnetization (DCD) remanence curves and Henkel plots. In contrast to what is observed in exchange spring <span class="hlt">magnets</span>, the IRM and DCD susceptibilities of all <span class="hlt">magnets</span> present peaks of nearly the same width, centered at roughly the same value of the <span class="hlt">magnetic</span> field, consistent with weak dipolar interactions between <span class="hlt">magnetic</span> particles. The IRM susceptibilities show structure associated with <span class="hlt">magnetic</span> inhomogenieties in the samples.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4189960','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4189960"><span id="translatedtitle">Recent <span class="hlt">Warming</span> of Lake Kivu</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Katsev, Sergei; Aaberg, Arthur A.; Crowe, Sean A.; Hecky, Robert E.</p> <p>2014-01-01</p> <p>Lake Kivu in East Africa has gained notoriety for its prodigious amounts of dissolved methane and dangers of limnic eruption. Being meromictic, it is also expected to accumulate heat due to rising regional air temperatures. To investigate the <span class="hlt">warming</span> trend and distinguish between atmospheric and geothermal heating sources, we compiled historical temperature data, performed measurements with logging instruments, and simulated heat propagation. We also performed isotopic analyses of water from the lake's main basin and isolated Kabuno Bay. The results reveal that the lake surface is <span class="hlt">warming</span> at the rate of 0.12C per decade, which matches the <span class="hlt">warming</span> rates in other East African lakes. Temperatures increase throughout the entire water column. Though <span class="hlt">warming</span> is strongest near the surface, <span class="hlt">warming</span> rates in the deep waters cannot be accounted for solely by propagation of atmospheric heat at presently assumed rates of vertical mixing. Unless the transport rates are significantly higher than presently believed, this indicates significant contributions from subterranean heat sources. Temperature time series in the deep monimolimnion suggest evidence of convection. The progressive deepening of the depth of temperature minimum in the water column is expected to accelerate the <span class="hlt">warming</span> in deeper waters. The <span class="hlt">warming</span> trend, however, is unlikely to strongly affect the physical stability of the lake, which depends primarily on salinity gradient. PMID:25295730</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25295730','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25295730"><span id="translatedtitle">Recent <span class="hlt">warming</span> of lake Kivu.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Katsev, Sergei; Aaberg, Arthur A; Crowe, Sean A; Hecky, Robert E</p> <p>2014-01-01</p> <p>Lake Kivu in East Africa has gained notoriety for its prodigious amounts of dissolved methane and dangers of limnic eruption. Being meromictic, it is also expected to accumulate heat due to rising regional air temperatures. To investigate the <span class="hlt">warming</span> trend and distinguish between atmospheric and geothermal heating sources, we compiled historical temperature data, performed measurements with logging instruments, and simulated heat propagation. We also performed isotopic analyses of water from the lake's main basin and isolated Kabuno Bay. The results reveal that the lake surface is <span class="hlt">warming</span> at the rate of 0.12C per decade, which matches the <span class="hlt">warming</span> rates in other East African lakes. Temperatures increase throughout the entire water column. Though <span class="hlt">warming</span> is strongest near the surface, <span class="hlt">warming</span> rates in the deep waters cannot be accounted for solely by propagation of atmospheric heat at presently assumed rates of vertical mixing. Unless the transport rates are significantly higher than presently believed, this indicates significant contributions from subterranean heat sources. Temperature time series in the deep monimolimnion suggest evidence of convection. The progressive deepening of the depth of temperature minimum in the water column is expected to accelerate the <span class="hlt">warming</span> in deeper waters. The <span class="hlt">warming</span> trend, however, is unlikely to strongly affect the physical stability of the lake, which depends primarily on salinity gradient. PMID:25295730</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1084068','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1084068"><span id="translatedtitle"><span class="hlt">Magnetic</span> nanohole superlattices</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Liu, Feng</p> <p>2013-05-14</p> <p>A <span class="hlt">magnetic</span> material is disclosed including a two-dimensional array of carbon <span class="hlt">atoms</span> and a two-dimensional array of nanoholes patterned in the two-dimensional array of carbon <span class="hlt">atoms</span>. The <span class="hlt">magnetic</span> material has long-range <span class="hlt">magnetic</span> ordering at a temperature below a critical temperature Tc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JOSAA..31.2511M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JOSAA..31.2511M"><span id="translatedtitle"><span class="hlt">Atomic</span> lighthouse effect</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mximo, C. E.; Kaiser, R.; Courteille, Ph. W.; Bachelard, R.</p> <p>2014-11-01</p> <p>We investigate the deflection of light by a cold <span class="hlt">atomic</span> cloud when the light-matter interaction is locally tuned via the Zeeman effect using <span class="hlt">magnetic</span> field gradients. This "lighthouse" effect is strongest in the single-scattering regime, where deviation of the incident field is largest. For optically dense samples, the deviation is reduced by collective effects, as the increase in linewidth leads to a decrease of the <span class="hlt">magnetic</span> field efficiency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25401364','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25401364"><span id="translatedtitle"><span class="hlt">Atomic</span> lighthouse effect.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mximo, C E; Kaiser, R; Courteille, Ph W; Bachelard, R</p> <p>2014-11-01</p> <p>We investigate the deflection of light by a cold <span class="hlt">atomic</span> cloud when the light-matter interaction is locally tuned via the Zeeman effect using <span class="hlt">magnetic</span> field gradients. This "lighthouse" effect is strongest in the single-scattering regime, where deviation of the incident field is largest. For optically dense samples, the deviation is reduced by collective effects, as the increase in linewidth leads to a decrease in <span class="hlt">magnetic</span> field efficiency. PMID:25401364</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4434777','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4434777"><span id="translatedtitle">Amplified Arctic <span class="hlt">warming</span> by phytoplankton under greenhouse <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Park, Jong-Yeon; Kug, Jong-Seong; Bader, Jürgen; Rolph, Rebecca; Kwon, Minho</p> <p>2015-01-01</p> <p>Phytoplankton have attracted increasing attention in climate science due to their impacts on climate systems. A new generation of climate models can now provide estimates of future climate change, considering the biological feedbacks through the development of the coupled physical–ecosystem model. Here we present the geophysical impact of phytoplankton, which is often overlooked in future climate projections. A suite of future <span class="hlt">warming</span> experiments using a fully coupled ocean−atmosphere model that interacts with a marine ecosystem model reveals that the future phytoplankton change influenced by greenhouse <span class="hlt">warming</span> can amplify Arctic surface <span class="hlt">warming</span> considerably. The <span class="hlt">warming</span>-induced sea ice melting and the corresponding increase in shortwave radiation penetrating into the ocean both result in a longer phytoplankton growing season in the Arctic. In turn, the increase in Arctic phytoplankton <span class="hlt">warms</span> the ocean surface layer through direct biological heating, triggering additional positive feedbacks in the Arctic, and consequently intensifying the Arctic <span class="hlt">warming</span> further. Our results establish the presence of marine phytoplankton as an important potential driver of the future Arctic climate changes. PMID:25902494</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25902494','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25902494"><span id="translatedtitle">Amplified Arctic <span class="hlt">warming</span> by phytoplankton under greenhouse <span class="hlt">warming</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Park, Jong-Yeon; Kug, Jong-Seong; Bader, Jürgen; Rolph, Rebecca; Kwon, Minho</p> <p>2015-05-12</p> <p>Phytoplankton have attracted increasing attention in climate science due to their impacts on climate systems. A new generation of climate models can now provide estimates of future climate change, considering the biological feedbacks through the development of the coupled physical-ecosystem model. Here we present the geophysical impact of phytoplankton, which is often overlooked in future climate projections. A suite of future <span class="hlt">warming</span> experiments using a fully coupled ocean-atmosphere model that interacts with a marine ecosystem model reveals that the future phytoplankton change influenced by greenhouse <span class="hlt">warming</span> can amplify Arctic surface <span class="hlt">warming</span> considerably. The <span class="hlt">warming</span>-induced sea ice melting and the corresponding increase in shortwave radiation penetrating into the ocean both result in a longer phytoplankton growing season in the Arctic. In turn, the increase in Arctic phytoplankton <span class="hlt">warms</span> the ocean surface layer through direct biological heating, triggering additional positive feedbacks in the Arctic, and consequently intensifying the Arctic <span class="hlt">warming</span> further. Our results establish the presence of marine phytoplankton as an important potential driver of the future Arctic climate changes. PMID:25902494</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5325997','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5325997"><span id="translatedtitle">Role of <span class="hlt">atomic</span> collisions in fusion</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Post, D.E.</p> <p>1982-04-01</p> <p><span class="hlt">Atomic</span> physics issues have played a large role in controlled fusion research. A general discussion of the present role of <span class="hlt">atomic</span> processes in both <span class="hlt">magnetic</span> and inertial controlled fusion work is presented.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22412952','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22412952"><span id="translatedtitle">Experimental evidence of <span class="hlt">warm</span> electron populations in magnetron sputtering plasmas</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sahu, B. B. Han, Jeon G.; Kim, Hye R.; Ishikawa, K.; Hori, M.</p> <p>2015-01-21</p> <p>This work report on the results obtained using the Langmuir probe (LP) measurements in high-power dc magnetron sputtering discharges. Data show clear evidence of two electron components, such as <span class="hlt">warm</span> and bulk electrons, in the sputtering plasma in a <span class="hlt">magnetic</span> trap. We have also used optical emission spectroscopy diagnostic method along with LP to investigate the plasma production. Data show that there is a presence of low-frequency oscillations in the 23?MHz range, which are expected to be generated by high-frequency waves. Analysis also suggests that the <span class="hlt">warm</span> electrons, in the plasmas, can be formed due to the collisionless Landau damping of the bulk electrons.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GeoJI.203..605D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GeoJI.203..605D"><span id="translatedtitle">Transition <span class="hlt">warming</span> and cooling remanences in pyrrhotite and hematite</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dunlop, David J.</p> <p>2015-10-01</p> <p><span class="hlt">Magnetic</span> minerals acquire a remanent <span class="hlt">magnetization</span> when cooled or <span class="hlt">warmed</span> in an applied field H through a phase transition. This paper reports the first observations of transition cooling and <span class="hlt">warming</span> remanent <span class="hlt">magnetizations</span> (TrCRM and TrWRM) in pyrrhotite (Fe7S8) and hematite (αFe2O3), with phase transitions at 32 K (Besnus transition) and 250 K (Morin transition). TrWRM was produced by <span class="hlt">warming</span> in a 2 mT field from 10 to 300 K and TrCRM by cooling in 2 mT from 300 to 10 K. In both experiments, <span class="hlt">magnetization</span> M was measured at 5 K intervals. The largest changes in M occurred over a 20 K interval flanking the Besnus or Morin transition but substantial changes also occurred away from any transition, presumably due to continuous changes in anisotropy. The triclinic low-temperature phase of pyrrhotite has high remanence efficiency compared to the room-temperature monoclinic phase. When H was zeroed at 300 K, only 35-40% of M survived as TrWRM, but in TrCRM experiments when H was zeroed at 10 K, practically 100% of M was preserved. After zero-field cooling to 10 K, 50-60% of TrWRM was retained but <15% of TrCRM survived zero-field <span class="hlt">warming</span> to 300 K. In hematite, both TrWRM of the room-temperature spin-canted phase and TrCRM of the low-temperature defect phase exist, as shown by net remanence production following complete <span class="hlt">warming</span>-cooling or cooling-<span class="hlt">warming</span> cycles between 10 and 300 K. Details of remanence acquisition/demagnetization in crossing the Morin transition could not be resolved, however. Symmetries were observed for both minerals. Single-domain size pyrrhotite crystals had mirror-image field-off and field-on <span class="hlt">warming</span> curves below 32 K, during TrWRM production/TrCRM loss at the 32 K transition, and up to ≈150 K. Submicron single-domain hematite had almost complete symmetry between field-off and field-on curves during cooling as well as <span class="hlt">warming</span>, both below and above the Morin transition but not in the transition region itself. This is the first time that mirror-image symmetries, observed previously for pseudo-single-domain and multidomain magnetite, have been documented for mineral grains in a single-domain state.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012NatGe...5..369S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012NatGe...5..369S"><span id="translatedtitle">Glaciology: Repeat <span class="hlt">warming</span> in Greenland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smith, Benjamin E.</p> <p>2012-06-01</p> <p>Greenland's glaciers have lost significant amounts of ice over the past decade. Rediscovered historical images of the ice margin show a record of southeast Greenland's response to the last major <span class="hlt">warming</span> event in the 1930s.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015A%26A...580A..77R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015A%26A...580A..77R"><span id="translatedtitle"><span class="hlt">Warm</span> and optically thick dissipative coronae above accretion disks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>R?a?ska, A.; Malzac, J.; Belmont, R.; Czerny, B.; Petrucci, P.-O.</p> <p>2015-08-01</p> <p>Context. In past years, several observations of AGN and X-ray binaries suggested the existence of a <span class="hlt">warm</span> (T ~ 0.5 - 1 keV) and optically thick (?cor ~ 10 - 20) corona covering the inner parts of the accretion disk. These properties are directly derived from spectral fitting in UV to soft-X-rays using Comptonization models. However, whether such a medium can be both in radiative and hydrostatic equilibrium with an accretion disk is still uncertain. Aims: We investigate the properties of such <span class="hlt">warm</span>, optically thick coronae and put constraints on their existence. Methods: We solve the radiative transfer equation for grey atmosphere analytically in a pure scattering medium, including local dissipation as an additional heating term in the <span class="hlt">warm</span> corona. The temperature profile of the <span class="hlt">warm</span> corona is calculated assuming that it is cooled by Compton scattering, with the underlying dissipative disk providing photons to the corona. Results: Our analytic calculations show that a dissipative thick corona (?cor in the range 10-12) on top of a standard accretion disk can reach temperatures of the order of 0.5-1 keV in its upper layers provided that the disk is passive. However, in the absence of strong <span class="hlt">magnetic</span> fields, the requirement of a Compton cooled corona in hydrostatic equilibrium in the vertical direction sets an upper limit on the Thomson optical depth ?cor ? 5. We show that this value cannot be exceeded independently of the accretion disk parameters. However, <span class="hlt">magnetic</span> pressure can extend this result to larger optical depths. Namely, a dissipative corona might have an optical depth up to ~20 when the <span class="hlt">magnetic</span> pressure is 100 times higher than the gas pressure. Conclusions: The observation of <span class="hlt">warm</span> coronae with Thomson depth larger than ?5 puts tight constraints on the physics of the accretion disk/corona systems and requires either strong <span class="hlt">magnetic</span> fields or vertical outflows to stabilize the system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.B11E..03B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.B11E..03B"><span id="translatedtitle">Soil <span class="hlt">Warming</span> and Carbon Release: Varying Patterns of Organic Matter Breakdown Across Five Ecosystems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Billings, S. A.; Barich, D.; Munson, E.</p> <p>2008-12-01</p> <p>Our understanding of the mechanisms governing soil organic carbon (SOC) retention vs. loss as CO2 in the future suffers from an inability to predict how mineralization of labile vs. recalcitrant SOC will proceed with <span class="hlt">warming</span>. Incubation and field studies of soil <span class="hlt">warming</span> have resulted in conflicting conclusions about how multiple SOC pools will respond to rising temperatures. In this study, we explore SOC transformations in a long-term incubation with <span class="hlt">warming</span> from five North American ecosystems by assessing respired CO2 and solid state 13C nuclear <span class="hlt">magnetic</span> resonance (NMR) spectra of non-incubated and cool vs. <span class="hlt">warm</span> incubated soils. We also quantified extra-cellular enzyme activities (EEA) late in the incubation to assess how relatively slow-turnover SOC pools responded to <span class="hlt">warming</span>. Soils from a cool temperate forest, a <span class="hlt">warm</span> temperate forest, and a temperate grassland released an average of 95% more CO2 when <span class="hlt">warmed</span> by the end of the 200 d incubation. Soils from a boreal forest and acidic arctic tundra released slightly more CO2 with <span class="hlt">warming</span> during the first 20 d of the incubation, but after day 20 and until day 200 CO2 released by <span class="hlt">warmed</span> soils was equivalent to the control soils. NMR spectra and EEA data suggest varying responses of these ecosystems' SOC pools to <span class="hlt">warming</span>. Arctic tundra soils did not experience a change in the kinds of C compounds mineralized with <span class="hlt">warming</span>, yet EEA data indicate greater acquisition of C from phenolic compounds. Boreal forest soil NMR spectra suggest greater net humification with <span class="hlt">warming</span>, with only slight increases in enzymatic C acquisition. These soils may have experienced an increase in C use efficiency with <span class="hlt">warming</span> that resulted in acquired C not being "wasted" on respiration. Cool temperate forest soils exhibited no change in the kinds of C accessed by microbes with <span class="hlt">warming</span>, as revealed via NMR, in spite of these soils' greater C acquisition and respiration with <span class="hlt">warming</span>. Grassland soils experienced an increase in humification with <span class="hlt">warming</span>, associated with an increase in CO2 released. <span class="hlt">Warm</span> temperate forest soils, in contrast, exhibited less humification with <span class="hlt">warming</span>. These data suggest that changing microbial C use efficiency with <span class="hlt">warming</span> is an important and relatively unexplored determinant governing the net influence of <span class="hlt">warming</span> on SOC transformations and eventual CO2 release.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NatPh..11..998C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NatPh..11..998C"><span id="translatedtitle">Quantum transport in ultracold <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chien, Chih-Chun; Peotta, Sebastiano; di Ventra, Massimiliano</p> <p>2015-12-01</p> <p>Ultracold <span class="hlt">atoms</span> confined by engineered <span class="hlt">magnetic</span> or optical potentials are ideal to study phenomena otherwise difficult to realize or probe in the solid state, thanks to the ability to control the <span class="hlt">atomic</span> interaction strength, number of species, density and geometry. Here, we review quantum transport phenomena in <span class="hlt">atomic</span> gases that mirror and can either better elucidate or show fundamental differences with respect to those observed in mesoscopic and nanoscopic systems. We discuss the significant progress in transport experiments in <span class="hlt">atomic</span> gases, the similarities and differences between transport in cold <span class="hlt">atoms</span> and in condensed matter systems, and survey theoretical predictions that are difficult to verify in conventional set-ups.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014RPPh...77e6502H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014RPPh...77e6502H"><span id="translatedtitle"><span class="hlt">Atom-by-atom</span> assembly</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hla, Saw Wai</p> <p>2014-05-01</p> <p><span class="hlt">Atomic</span> manipulation using a scanning tunneling microscope (STM) tip enables the construction of quantum structures on an <span class="hlt">atom-by-atom</span> basis, as well as the investigation of the electronic and dynamical properties of individual <span class="hlt">atoms</span> on a one-<span class="hlt">atom</span>-at-a-time basis. An STM is not only an instrument that is used to see individual <span class="hlt">atoms</span> by means of imaging, but is also a tool that is used to touch and take the <span class="hlt">atoms</span>, or to hear their movements. Therefore, the STM can be considered as the eyes, hands and ears of the scientists, connecting our macroscopic world to the exciting <span class="hlt">atomic</span> world. In this article, various STM <span class="hlt">atom</span> manipulation schemes and their example applications are described. The future directions of <span class="hlt">atomic</span> level assembly on surfaces using scanning probe tips are also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016LNP...911..111E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016LNP...911..111E"><span id="translatedtitle">Cold <span class="hlt">Atom</span> Magnetometers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eto, Yujiro; Sadrove, Mark; Hirano, Takuya</p> <p></p> <p>Detection of weak <span class="hlt">magnetic</span> fields with high spatial resolution is an important technology for various applications such as biological imaging, detection of MRI signals and fundamental physics. Cold <span class="hlt">atom</span> magnetometry enables 10-11 T/ <math xmlns:xlink="http://www.w3.org/1999/xlink"> <msqrt> <mrow> <mtext>Hz</mtext> </mrow> </msqrt> sqrt{text{Hz}} sensitivities at the micron scale, that is, at the scale of a typical biological cell size. This magnetometry takes advantage of unique properties of <span class="hlt">atomic</span> gaseous Bose-Einstein condensates with internal spin degrees of freedom. In this chapter, we first overview various state-of-the-art magnetometers, addressing their sensitivities and spatial resolutions. Then we describe properties of spinor condensates, ultracold <span class="hlt">atom</span> magnetometers, and the latest research developments achieved in the FIRST project, especially for the detection of alternate current <span class="hlt">magnetic</span> fields using a spin-echo-based magnetometer. We also discuss future prospects of the magnetometers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvL.115d3602C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvL.115d3602C"><span id="translatedtitle"><span class="hlt">Atom</span>-Light Hybrid Interferometer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Bing; Qiu, Cheng; Chen, Shuying; Guo, Jinxian; Chen, L. Q.; Ou, Z. Y.; Zhang, Weiping</p> <p>2015-07-01</p> <p>A new type of hybrid <span class="hlt">atom</span>-light interferometer is demonstrated with <span class="hlt">atomic</span> Raman amplification processes replacing the beam splitting elements in a traditional interferometer. This nonconventional interferometer involves correlated optical and <span class="hlt">atomic</span> waves in the two arms. The correlation between <span class="hlt">atoms</span> and light developed with the Raman process makes this interferometer different from conventional interferometers with linear beam splitters. It is observed that the high-contrast interference fringes are sensitive to the optical phase via a path change as well as the <span class="hlt">atomic</span> phase via a <span class="hlt">magnetic</span> field change. This new <span class="hlt">atom</span>-light correlated hybrid interferometer is a sensitive probe of the <span class="hlt">atomic</span> internal state and should find wide applications in precision measurement and quantum control with <span class="hlt">atoms</span> and photons.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26252684','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26252684"><span id="translatedtitle"><span class="hlt">Atom</span>-Light Hybrid Interferometer.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chen, Bing; Qiu, Cheng; Chen, Shuying; Guo, Jinxian; Chen, L Q; Ou, Z Y; Zhang, Weiping</p> <p>2015-07-24</p> <p>A new type of hybrid <span class="hlt">atom</span>-light interferometer is demonstrated with <span class="hlt">atomic</span> Raman amplification processes replacing the beam splitting elements in a traditional interferometer. This nonconventional interferometer involves correlated optical and <span class="hlt">atomic</span> waves in the two arms. The correlation between <span class="hlt">atoms</span> and light developed with the Raman process makes this interferometer different from conventional interferometers with linear beam splitters. It is observed that the high-contrast interference fringes are sensitive to the optical phase via a path change as well as the <span class="hlt">atomic</span> phase via a <span class="hlt">magnetic</span> field change. This new <span class="hlt">atom</span>-light correlated hybrid interferometer is a sensitive probe of the <span class="hlt">atomic</span> internal state and should find wide applications in precision measurement and quantum control with <span class="hlt">atoms</span> and photons. PMID:26252684</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMGC32A..02F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMGC32A..02F"><span id="translatedtitle">The Great <span class="hlt">Warming</span> Brian Fagan</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fagan, B. M.</p> <p>2010-12-01</p> <p>The Great <span class="hlt">Warming</span> is a journey back to the world of a thousand years ago, to the Medieval <span class="hlt">Warm</span> Period. Five centuries of irregular <span class="hlt">warming</span> from 800 to 1250 had beneficial effects in Europe and the North Atlantic, but brought prolonged droughts to much of the Americas and lands affected by the South Asian monsoon. The book describes these impacts of <span class="hlt">warming</span> on medieval European societies, as well as the Norse and the Inuit of the far north, then analyzes the impact of harsh, lengthy droughts on hunting societies in western North America and the Ancestral Pueblo farmers of Chaco Canyon, New Mexico. These peoples reacted to drought by relocating entire communities. The Maya civilization was much more vulnerable that small-scale hunter-gatherer societies and subsistence farmers in North America. Maya rulers created huge water storage facilities, but their civilization partially collapsed under the stress of repeated multiyear droughts, while the Chimu lords of coastal Peru adapted with sophisticated irrigation works. The climatic villain was prolonged, cool La Niñalike conditions in the Pacific, which caused droughts from Venezuela to East Asia, and as far west as East Africa. The Great <span class="hlt">Warming</span> argues that the <span class="hlt">warm</span> centuries brought savage drought to much of humanity, from China to Peru. It also argues that drought is one of the most dangerous elements in today’s humanly created global <span class="hlt">warming</span>, often ignored by preoccupied commentators, but with the potential to cause over a billion people to starve. Finally, I use the book to discuss the issues and problems of communicating multidisciplinary science to the general public.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApPhB.119..435K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApPhB.119..435K"><span id="translatedtitle">Production of <span class="hlt">warm</span> aluminum cluster anions by femtosecond laser ablation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kobayashi, T.; Matsuo, Y.</p> <p>2015-06-01</p> <p>We report on the production of <span class="hlt">warm</span> aluminum cluster anions, Al{/n -} (1 ? n ? 26), after femtosecond laser ablation of an aluminum nitride substrate. Large cluster anions of n ? 8 suffer metastable dissociation after their production, which indicates the internal energy of the cluster anions is high enough for the dissociation of an Al <span class="hlt">atom</span>. We find that the efficiency of metastable dissociation is dependent on the size of cluster anions and the dependence can be rationalized by the dissociation energy of an Al <span class="hlt">atom</span> from the cluster anions calculated with thermochemical data of the clusters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012APS..MAR.K1261H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012APS..MAR.K1261H"><span id="translatedtitle"><span class="hlt">Atoms</span> talking to SQUIDs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hoffman, J. E.; Grover, J. A.; Ravets, S.; Voigt, K. D.; Lee, J.; Kim, Z.; Wood, A. K.; Schoch, I.; Anderson, J. R.; Dragt, A. J.; Hafezi, M.; Lobb, C. J.; Orozco, L. A.; Rolston, S. L.; Taylor, J. M.; Wellstood, F. C.</p> <p>2012-02-01</p> <p>We present our advances towards a hybrid quantum system of ^87Rb <span class="hlt">atoms</span> coupled to a superconducting flux qubit through the <span class="hlt">magnetic</span> dipole transition. We plan to trap <span class="hlt">atoms</span> in the evanescent field outside a 500 nm nanofiber. This will allow us to bring the <span class="hlt">atoms</span> less than 5 μm above the surface of the superconductor without producing excessive heating or changing <span class="hlt">magnetic</span> fields. As an intermediate step, we plan on coupling the <span class="hlt">atoms</span> to a superconducting LC resonator. Current progress includes production of nanofibers with >98% transmission, and a tunable high-Q superconducting resonator. Additionally, we show how to use our system as a unified interface for microwave and optical photons, in which the <span class="hlt">atoms</span> act both as a quantum memory and transduce excitations between the two frequency domains. Using coherent control techniques, we examine conversion and storage of quantum information between microwave photons in superconducting resonators, ensembles of ultracold <span class="hlt">atoms</span>, and optical photons as well as a method for transferring information between two resonators.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014NatCC...4..143Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014NatCC...4..143Z"><span id="translatedtitle">How <span class="hlt">warm</span> days increase belief in global <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zaval, Lisa; Keenan, Elizabeth A.; Johnson, Eric J.; Weber, Elke U.</p> <p>2014-02-01</p> <p>Climate change judgements can depend on whether today seems warmer or colder than usual, termed the local <span class="hlt">warming</span> effect. Although previous research has demonstrated that this effect occurs, studies have yet to explain why or how temperature abnormalities influence global <span class="hlt">warming</span> attitudes. A better understanding of the underlying psychology of this effect can help explain the public's reaction to climate change and inform approaches used to communicate the phenomenon. Across five studies, we find evidence of attribute substitution, whereby individuals use less relevant but available information (for example, today's temperature) in place of more diagnostic but less accessible information (for example, global climate change patterns) when making judgements. Moreover, we rule out alternative hypotheses involving climate change labelling and lay mental models. Ultimately, we show that present temperature abnormalities are given undue weight and lead to an overestimation of the frequency of similar past events, thereby increasing belief in and concern for global <span class="hlt">warming</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740010901','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740010901"><span id="translatedtitle">Analysis of data from spacecraft (stratospheric <span class="hlt">warmings</span>)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Anderson, A. D.</p> <p>1974-01-01</p> <p>Links between the upper atmosphere and the stratosphere were studied to explain stratospheric <span class="hlt">warmings</span>, and to correlate the <span class="hlt">warmings</span> with other terrestrial and solar phenomena. Physical mechanisms for <span class="hlt">warming</span>, or which may act as a trigger are discussed along with solar and geophysical indices. Two stratospheric <span class="hlt">warming</span> cases are analyzed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=ups&id=EJ925234','ERIC'); return false;" href="http://eric.ed.gov/?q=ups&id=EJ925234"><span id="translatedtitle">Active Movement <span class="hlt">Warm</span>-Up Routines</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Walter, Teri; Quint, Ashleigh; Fischer, Kim; Kiger, Joy</p> <p>2011-01-01</p> <p>This article presents <span class="hlt">warm</span>-ups that are designed to physiologically and psychologically prepare students for vigorous physical activity. An active movement <span class="hlt">warm</span>-up routine is made up of three parts: (1) active <span class="hlt">warm</span>-up movement exercises, (2) general preparation, and (3) the energy system. These <span class="hlt">warm</span>-up routines can be used with all grade levels</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25865795','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25865795"><span id="translatedtitle">Selenium speciation using capillary electrophoresis coupled with modified electrothermal <span class="hlt">atomic</span> absorption spectrometry after selective extraction with 5-sulfosalicylic acid functionalized <span class="hlt">magnetic</span> nanoparticles.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yan, Lizhen; Deng, Biyang; Shen, Caiying; Long, Chanjuan; Deng, Qiufen; Tao, Chunyao</p> <p>2015-05-22</p> <p>A new method for selenium speciation in fermented bean curd wastewater and juice was described. This method involved sample extraction with 5-sulfosalicylic acid (SSA)-functionalized silica-coated <span class="hlt">magnetic</span> nanoparticles (SMNPs), capillary electrophoresis (CE) separation, and online detection with a modified electrothermal <span class="hlt">atomic</span> absorption spectrometry (ETAAS) system. The modified interface for ETAAS allowed for the introduction of CE effluent directly through the end of the graphite tube. Elimination of the upper injection hole of the graphite tube reduced the loss of the anlayte and enhanced the detection sensitivity. The SSA-SMNPs were synthesized and used to extract trace amounts of selenite [Se(IV)], selenite [Se(VI)], selenomethionine (SeMet), and selenocystine (SeCys2) from dilute samples. The concentration enrichment factors for Se(VI), Se(IV), SeMet, and SeCys2 were 21, 29, 18, and 12, respectively, using the SSA-SMNPs extraction. The limits of detection for Se(VI), Se(IV), SeMet, and SeCys2 were 0.18, 0.17, 0.54, 0.49ngmL(-1), respectively. The RSD values (n=6) of method for intraday were observed between 0.7% and 2.9%. The RSD values of method for interday were less than 3.5%. The linear range of Se(VI) and Se(IV) were in the range of 0.5-200ngmL(-1), and the linear ranges of SeMet and SeCys2 were 2-500 and 2-1000ngmL(-1), respectively. The detection limits of this method were improved by 10 times due to the enrichment by the SSA-SMNP extraction. The contents of Se(VI) and Se(IV) in fermented bean curd wastewater were measured as 3.83 and 2.62ngmL(-1), respectively. The contents of Se(VI), Se(IV), SeMet, and SeCys2 in fermented bean curd juice were determined as 6.39, 4.08, 2.77, and 4.00ngmL(-1), respectively. The recoveries were in the range of 99.14-104.5% and the RSDs (n=6) of recoveries between 0.82% and 3.5%. PMID:25865795</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1195936','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1195936"><span id="translatedtitle">High data rate <span class="hlt">atom</span> interferometric device</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Biedermann, Grant; McGuinness, Hayden James Evans; Rakholia, Akash</p> <p>2015-07-21</p> <p>A light-pulse <span class="hlt">atomic</span> interferometry (LPAI) apparatus is provided. The LPAI apparatus comprises a vessel, two sets of <span class="hlt">magnetic</span> coils configured to <span class="hlt">magnetically</span> confine an <span class="hlt">atomic</span> vapor in two respective magneto-optical traps (MOTs) within the vessel when activated, and an optical system configured to irradiate the <span class="hlt">atomic</span> vapor within the vessel with laser radiation that, when suitably tuned, can launch <span class="hlt">atoms</span> previously confined in each of the MOTs toward the other MOT. In embodiments, the <span class="hlt">magnetic</span> coils are configured to produce a <span class="hlt">magnetic</span> field that is non-zero at the midpoint between the traps. In embodiments, the time-of-flight of the launched <span class="hlt">atoms</span> from one MOT to the other is 12 ms or less. In embodiments, the MOTs are situated approximately 36 mm apart. In embodiments, the apparatus is configured to activate the <span class="hlt">magnetic</span> coils according to a particular temporal <span class="hlt">magnetic</span> field gradient profile.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/530884','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/530884"><span id="translatedtitle"><span class="hlt">Warming</span> early Earth and Mars</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kasting, J.F.</p> <p>1997-05-23</p> <p>Sagan and Chyba, in their article on page 1217 of this issue, have revived an old debate about how liquid water was maintained on early Earth and Mars despite a solar luminosity 25 to 30% lower than that at present. A theory that has been popular for some time is that greatly elevated concentrations of atmospheric COD produced by the action of the carbonate-silicate cycle, provided enough of a greenhouse effect to <span class="hlt">warm</span> early Earth. However, Rye et al. have placed geochemical constraints on early atmospheric CO{sub 2} abundances that fall well below the levels needed to <span class="hlt">warm</span> the surface. These constraints are based on the absence of siderite (FeCO{sub 3}) in ancient soil profiles-a negative and, hence, rather weak form of evidence- and apply to the time period 2.2 to 2.8 billion years ago, when Earth was already middle aged. Nonetheless, the soil data provide some indication that atmospheric CO{sub 2} levels may have been lower than previously thought. An even more serious problem arises if one tries to keep early Mars <span class="hlt">warm</span> with CO{sub 2}. Model calculations predict that CO{sub 2} clouds would form on Mars in the upper troposphere, reducing the lapse rate and severely limiting the amount of surface <span class="hlt">warming</span>. A suggestion that CO{sub 2} clouds may have <span class="hlt">warmed</span> the planet radiatively has yet to be borne out by detailed calculations. 26 refs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21052870','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21052870"><span id="translatedtitle">Cosmic Rays and Global <span class="hlt">Warming</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sloan, T.; Wolfendale, A. W.</p> <p>2008-01-24</p> <p>Some workers have claimed that the observed temporal correlations of (low level) terrestrial cloud cover with the cosmic ray intensity changes, due to solar modulation, are causal. The possibility arises, therefore, of a connection between cosmic rays and Global <span class="hlt">Warming</span>. If true, the implications would be very great. We have examined this claim in some detail. So far, we have not found any evidence in support and so our conclusions are to doubt it. From the absence of corroborative evidence we estimate that less than 15% at the 95% confidence level, of the 11-year cycle <span class="hlt">warming</span> variations are due to cosmic rays and less than 2% of the <span class="hlt">warming</span> over the last 43 years is due to this cause. The origin of the correlation itself is probably the cycle of solar irradiance although there is, as yet, no certainty.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000EOSTr..81Q.266S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000EOSTr..81Q.266S"><span id="translatedtitle">Global <span class="hlt">warming</span> at the summit</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Showstack, Randy</p> <p></p> <p>During the recent summit meeting between Russian President Vladimir Putin and U.S. President Bill Clinton, the two leaders reaffirmed their concerns about global <span class="hlt">warming</span> and the need to continue to take actions to try to reduce the threat.In a June 4 joint statement, they stressed the need to develop flexibility mechanisms, including international emissions trading, under the Kyoto Protocol to the United Nations Framework Convention on Climate Change. They also noted that initiatives to reduce the risk of greenhouse <span class="hlt">warming</span>, including specific mechanisms of the Kyoto Protocol, could potentially promote economic growth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920006216','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920006216"><span id="translatedtitle">Halocarbon ozone depletion and global <span class="hlt">warming</span> potentials</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cox, Richard A.; Wuebbles, D.; Atkinson, R.; Connell, Peter S.; Dorn, H. P.; Derudder, A.; Derwent, Richard G.; Fehsenfeld, F. C.; Fisher, D.; Isaksen, Ivar S. A.</p> <p>1990-01-01</p> <p>Concern over the global environmental consequences of fully halogenated chlorofluorocarbons (CFCs) has created a need to determine the potential impacts of other halogenated organic compounds on stratospheric ozone and climate. The CFCs, which do not contain an H <span class="hlt">atom</span>, are not oxidized or photolyzed in the troposphere. These compounds are transported into the stratosphere where they decompose and can lead to chlorine catalyzed ozone depletion. The hydrochlorofluorocarbons (HCFCs or HFCs), in particular those proposed as substitutes for CFCs, contain at least one hydrogen <span class="hlt">atom</span> in the molecule, which confers on these compounds a much greater sensitivity toward oxidation by hydroxyl radicals in the troposphere, resulting in much shorter atmospheric lifetimes than CFCs, and consequently lower potential for depleting ozone. The available information is reviewed which relates to the lifetime of these compounds (HCFCs and HFCs) in the troposphere, and up-to-date assessments are reported of the potential relative effects of CFCs, HCFCs, HFCs, and halons on stratospheric ozone and global climate (through 'greenhouse' global <span class="hlt">warming</span>).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22390940','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22390940"><span id="translatedtitle"><span class="hlt">Atomic</span> polarizabilities</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Safronova, M. S.; Mitroy, J.; Clark, Charles W.; Kozlov, M. G.</p> <p>2015-01-22</p> <p>The <span class="hlt">atomic</span> dipole polarizability governs the first-order response of an <span class="hlt">atom</span> to an applied electric field. <span class="hlt">Atomic</span> polarization phenomena impinge upon a number of areas and processes in physics and have been the subject of considerable interest and heightened importance in recent years. In this paper, we will summarize some of the recent applications of <span class="hlt">atomic</span> polarizability studies. A summary of results for polarizabilities of noble gases, monovalent, and divalent <span class="hlt">atoms</span> is given. The development of the CI+all-order method that combines configuration interaction and linearized coupled-cluster approaches is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21208117','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21208117"><span id="translatedtitle"><span class="hlt">Atom</span> interferometers and <span class="hlt">atom</span> holography</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Shimizu, Fujio; Mitake, Satoru; Fujita, Jun-ichi; Morinaga, Makoto; Kishimoto, Tetsuo</p> <p>1999-06-11</p> <p>Various techniques of <span class="hlt">atom</span> manipulation with a binary hologram are discussed and demonstrated experimentally. An <span class="hlt">atomic</span> beam of metastable neon in the 1s{sub 3} state and a SiN thin film with holes that expresses the transmission function of the hologram are used to demonstrate this technique. The gray-scale holography of <span class="hlt">atoms</span> is demonstrated for the first time. Other possibilities of holographic manipulation of <span class="hlt">atoms</span> are also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/281569','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/281569"><span id="translatedtitle"><span class="hlt">Magnetic</span>-field dependence of the cross section for collisional disorientation of 6{sup 2}P{sub 1/2}Cs and 5{sup 2}P{sub 1/2}Rb <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kedzierski, Ju.W.; Baylis, W.E.; Krause, L.</p> <p>1993-05-01</p> <p>Cesium vapor contained together with a few torr of helium in a quartz cell, maintained at 35{degrees}C and located in a variable 1.5-7.0T <span class="hlt">magnetic</span> field, was irradiated with light from a pulsed dye laser producing selective excitation of the m{sub j} = -1/2 (6{sup 2}P{sub 1/2}) Zeeman substate. Collisions of the excited and oriented Cs <span class="hlt">atoms</span> with the ground-state He <span class="hlt">atoms</span> induced transfer to the m{sub j} = +1/2 substate. The 6{sup 2}P{sub 1/2} {yields} 6{sup 1}S{sub 1/2} decay of the Zeeman substates produced a fluorescence spectrum which was resolved with a piezoelectrically scanned Fabry-Perot interferometer. Measurements of the relative intensities of the m{sub j} = +1/2 and m{sub j} = -1/2 fluorescence components in relation to the buffer-gas pressure yielded the cross sections for disorientation of the 6{sup 2}P{sub 1/2} Cs <span class="hlt">atoms</span>, which are significantly larger at fields 1.5-7.0T than at zero field or at fields in the range 0-1T. Beyond 1T the cross section continues to increase, reaches a maximum near 3T and becomes approximately constant above 5T. A similar experiment with 5{sup 2}P{sub 1/2} Rb <span class="hlt">atoms</span> indicated no increase in the disorientation cross section with <span class="hlt">magnetic</span> field. The salient features of the experimental observations are confirmed by independent theoretical calculations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008APS..MARY12007R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008APS..MARY12007R"><span id="translatedtitle">The Alternate <span class="hlt">Atomic</span> Model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ragland, Evan</p> <p>2008-03-01</p> <p>An alternate <span class="hlt">atomic</span> model posits concentric electron and nucleon fields spinning together about an empty center. It is alternative to the generally accepted planetary system in which electron point particles orbit about a center clump of nucleon point particles. Introduced in 1992 as an alternative to the standard model of the nucleus it applies scientific space-time knowledge unknown when the standard model was conceived. Originally advanced in the spirit of alternative equivalence it evolved to model the entire <span class="hlt">atomic</span> structure plus many features of space-time. Structural definitions assume space-time properties of: unidirectional expansion, special relativity, electrical field, <span class="hlt">magnetic</span> field, spin field, gravity field, and space-time surface effect. Field effects are associated with Faraday lines of field force. Model properties feature symmetry and complementarily. Mass structures of the electron, proton,neutron, and protium <span class="hlt">atom</span> plus the <span class="hlt">atomic</span> and nuclear constituencies of all elements are developed. In addition the nuclear strong force is defined, the <span class="hlt">magnetic</span> anomaly explained, etc. Model logic constructs the neutron as the complement of the hydrogen (protium) <span class="hlt">atom</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19840046443&hterms=Atomic+structure&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3D%2528Atomic%2Bstructure%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19840046443&hterms=Atomic+structure&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3D%2528Atomic%2Bstructure%2529"><span id="translatedtitle">The direct measurement of the 3 3P0-3 3P1 fine-structure interval and the gJ-factor of <span class="hlt">atomic</span> silicon by laser <span class="hlt">magnetic</span> resonance</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Evenson, K. M.; Beltran-Lopez, V.; Ley-Koo, E.; Inguscio, M.</p> <p>1984-01-01</p> <p>The J - 1 fine structure interval and the g-factor of the 3P1 state have been determined with high precision in the present laser <span class="hlt">magnetic</span> resonance measurements of the ground 3p2 3P multiplet of <span class="hlt">atomic</span> Si. Delta-E(3P1-3P0) = 2,311,755.6(7) MHz, and gJ(3P1) = 1.500830(70). Single-configuration calculations of gJ for 3P1 and 3P2 yield a value for the latter which, at 1.501095, is noted to differ by an unexpectedly large margin from the experimental value.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/245296','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/245296"><span id="translatedtitle"><span class="hlt">Warming</span> up to solar energy</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Biondo, B.</p> <p>1996-07-01</p> <p>Increasingly alarmed by threats to their financial security posed by an escalating number of weather-related catastrophes, major insurance companaies, particularly those in Europe and Asia, are starting to support a variety of measures that would slowe the production of grenhouse gases worlwide. As the insurance and banking industries turn their attention to global <span class="hlt">warming</span>, investments in solar energy take on growing appeal.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003GPC....39..215H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003GPC....39..215H"><span id="translatedtitle"><span class="hlt">Warming</span> permafrost in European mountains</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Harris, Charles; Vonder Mhll, Daniel; Isaksen, Ketil; Haeberli, Wilfried; Sollid, Johan Ludvig; King, Lorenz; Holmlund, Per; Dramis, Francesco; Guglielmin, Mauro; Palacios, David</p> <p>2003-11-01</p> <p>Here we present the first systematic measurements of European mountain permafrost temperatures from a latitudinal transect of six boreholes extending from the Alps, through Scandinavia to Svalbard. Boreholes were drilled in bedrock to depths of at least 100 m between May 1998 and September 2000. Geothermal profiles provide evidence for regional-scale secular <span class="hlt">warming</span>, since all are nonlinear, with near-surface <span class="hlt">warm</span>-side temperature deviations from the deeper thermal gradient. Topographic effects lead to variability between Alpine sites. First approximation estimates, based on curvature within the borehole thermal profiles, indicate a maximum ground surface <span class="hlt">warming</span> of +1 C in Svalbard, considered to relate to thermal changes in the last 100 years. In addition, a 15-year time series of thermal data from the 58-m-deep Murtl-Corvatsch permafrost borehole in Switzerland, drilled in creeping frozen ice-rich rock debris, shows an overall <span class="hlt">warming</span> trend, but with high-amplitude interannual fluctuations that reflect early winter snow cover more strongly than air temperatures. Thus interpretation of the deeper borehole thermal histories must clearly take account of the potential effects of changing snow cover in addition to atmospheric temperatures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5911414','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5911414"><span id="translatedtitle">Global <span class="hlt">warming</span> on Capitol Hill</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Berg, T.F.</p> <p>1991-09-01</p> <p>This article reports on hearings in both congressional houses on ozone depletion and global <span class="hlt">warming</span>. Topics covered include the drought in California, effect on electric rates, administration policy relating to international efforts to cut greenhouse gas, freons phaseout, methane emission phaseout, and energy efficiency provisions for buildings and vehicles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5495825','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5495825"><span id="translatedtitle">Policy implications of greenhouse <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Not Available</p> <p>1991-01-01</p> <p>Contents: background; the greenhouse gases and their effects; policy framework; adaptation; mitigation; international considerations; findings and conclusions; recommendations; questions and answers about greenhouse <span class="hlt">warming</span>; background information on synthesis panel members and professional staff; and membership lists for effects, mitigation, and adaptation panels.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPhCS.655a2026A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPhCS.655a2026A"><span id="translatedtitle"><span class="hlt">Magnetic</span> refrigeration: an eco-friendly technology for the refrigeration at room temperature</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aprea, C.; Greco, A.; Maiorino, A.; Masselli, C.</p> <p>2015-11-01</p> <p><span class="hlt">Magnetic</span> refrigeration is an emerging, environment-friendly technology based on a <span class="hlt">magnetic</span> solid that acts as a refrigerant by magneto-caloric effect (MCE). In the case of ferromagnetic materials MCE is a <span class="hlt">warming</span> as the <span class="hlt">magnetic</span> moments of the <span class="hlt">atom</span> are aligned by the application of a <span class="hlt">magnetic</span> field, and the corresponding cooling upon removal of the <span class="hlt">magnetic</span> field. There are two types of <span class="hlt">magnetic</span> phase changes that may occur at the Curie point: first order <span class="hlt">magnetic</span> transition (FOMT) and second order <span class="hlt">magnetic</span> transition (SOMT). The reference cycle for <span class="hlt">magnetic</span> refrigeration is AMR (Active <span class="hlt">Magnetic</span> Regenerative cycle) where the <span class="hlt">magnetic</span> material matrix works both as a refrigerating medium and as a heat regenerating medium, while the fluid flowing in the porous matrix works as a heat transfer medium. Regeneration can be accomplished by blowing a heat transfer fluid in a reciprocating fashion through the regenerator made of magnetocaloric material that is alternately <span class="hlt">magnetized</span> and demagnetized. In this paper, attention is directed towards the near room-temperature range. We compare the energetic performance of a commercial R134a refrigeration plant to that of a <span class="hlt">magnetic</span> refrigerator working with an AMR cycle. Attention is devoted to the evaluation of the environmental impact in terms of a greenhouse effect. The comparison is performed in term of TEWI index (Total Equivalent <span class="hlt">Warming</span> Impact) that takes into account both direct and indirect contributions to global <span class="hlt">warming</span>. In this paper the AMR cycle works with different <span class="hlt">magnetic</span> refrigerants: pure gadolinium, second order phase <span class="hlt">magnetic</span> transition (Pr0.45Sr0.35MnO3) and first order phase <span class="hlt">magnetic</span> transition alloys (Gd5Si2Ge2, LaFe11.384Mn0.356Si1.26H1.52, LaFe1105Co0.94Si110 and MnFeP0.45As0.55). The comparison, carried out by means of a mathematical model, clearly shows that GdSi2Ge2 and LaFe11.384Mn0.356Si1.26H1.52 has a TEWI index always lower than that of a vapor compression plant. Furthermore, the TEWI of the AMR cycle working with FOMT materials is always better than that of SOMT materials. Gd5Si2Ge2 is the best FOMT material.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012NatCC...2..530K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012NatCC...2..530K"><span id="translatedtitle">Equatorial refuge amid tropical <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karnauskas, Kristopher B.; Cohen, Anne L.</p> <p>2012-07-01</p> <p>Upwelling across the tropical Pacific Ocean is projected to weaken in accordance with a reduction of the atmospheric overturning circulation, enhancing the increase in sea surface temperature relative to other regions in response to greenhouse-gas forcing. In the central Pacific, home to one of the largest marine protected areas and fishery regions in the global tropics, sea surface temperatures are projected to increase by 2.8C by the end of this century. Of critical concern is that marine protected areas may not provide refuge from the anticipated rate of large-scale <span class="hlt">warming</span>, which could exceed the evolutionary capacity of coral and their symbionts to adapt. Combining high-resolution satellite measurements, an ensemble of global climate models and an eddy-resolving regional ocean circulation model, we show that <span class="hlt">warming</span> and productivity decline around select Pacific islands will be mitigated by enhanced upwelling associated with a strengthening of the equatorial undercurrent. Enhanced topographic upwelling will act as a negative feedback, locally mitigating the surface <span class="hlt">warming</span>. At the Gilbert Islands, the rate of <span class="hlt">warming</span> will be reduced by 0.7+/-0.3C or 25+/-9% per century, or an overall cooling effect comparable to the local anomaly for a typical El Nio, by the end of this century. As the equatorial undercurrent is dynamically constrained to the Equator, only a handful of coral reefs stand to benefit from this equatorial island effect. Nevertheless, those that do face a lower rate of <span class="hlt">warming</span>, conferring a significant advantage over neighbouring reef systems. If realized, these predictions help to identify potential refuges for coral reef communities from anticipated climate changes of the twenty-first century.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhDT.......114T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhDT.......114T"><span id="translatedtitle">Linear <span class="hlt">Atom</span> Guides: Guiding Rydberg <span class="hlt">Atoms</span> and Progress Toward an <span class="hlt">Atom</span> Laser</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Traxler, Mallory A.</p> <p></p> <p>In this thesis, I explore a variety of experiments within linear, two-wire, <span class="hlt">magnetic</span> <span class="hlt">atom</span> guides. Experiments include guiding of Rydberg <span class="hlt">atoms</span>; transferring between states while keeping the <span class="hlt">atoms</span> contained within the guide; and designing, constructing, and testing a new experimental apparatus. The ultimate goal of the <span class="hlt">atom</span> guiding experiments is to develop a continuous <span class="hlt">atom</span> laser. The guiding of 87Rb 59D5/2 Rydberg <span class="hlt">atoms</span> is demonstrated. The evolution of the <span class="hlt">atoms</span> is driven by the combined effects of dipole forces acting on the center-of-mass degree of freedom as well as internal-state transitions. Time delayed microwave and state-selective field ionization, along with ion detection, are used to investigate the evolution of the internal-state distribution as well as the Rydberg <span class="hlt">atom</span> motion while traversing the guide. The observed decay time of the guided-<span class="hlt">atom</span> signal is about five times that of the initial state. A population transfer between Rydberg states contributes to this lengthened lifetime, and also broadens the observed field ionization spectrum. The population transfer is attributed to thermal transitions and, to a lesser extent, initial state-mixing due to Rydberg-Rydberg collisions. Characteristic signatures in ion time-of-flight signals and spatially resolved images of ion distributions, which result from the coupled internal-state and center-of-mass dynamics, are discussed. Some groups have used a scheme to make BECs where <span class="hlt">atoms</span> are optically pumped from one reservoir trap to a final state trap, irreversibly transferring those <span class="hlt">atoms</span> from one trap to the other. In this context, transfer from one guided ground state to another is studied. In our setup, before the <span class="hlt">atoms</span> enter the guide, they are pumped into the | F = 1, mF = --1> state. Using two repumpers, one tuned to the F = 1 ? F' = 0 transition (R10) and the other tuned to the F = 1 ? F' = 2 transition (R12), the <span class="hlt">atoms</span> are pumped between these guided states. <span class="hlt">Magnetic</span> reflections within the guide are also studied. Design and construction of a new linear <span class="hlt">magnetic</span> <span class="hlt">atom</span> guide is detailed. This guide beta has many improvements over the original guide alpha: a Zeeman slower, <span class="hlt">magnetic</span> injection, a physical shutter, and surface adsorption evaporative cooling are some of the main changes. Testing of this new system is underway. It is hoped that the improvements to guide beta will yield an <span class="hlt">atom</span> density sufficient to reach degeneracy, thereby forming a continuous BEC at the end of the guide. The BEC, which will be continuously replenished by the <span class="hlt">atoms</span> within the guide, will be outcoupled to form a continuous <span class="hlt">atom</span> laser.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SurSc.646..261G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SurSc.646..261G"><span id="translatedtitle">Environment dependence of <span class="hlt">magnetic</span> moment and <span class="hlt">atomic</span> level shifts within tight-binding approximation: An illustration in the case of cobalt</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Goyhenex, C.; Tréglia, G.; Legrand, B.</p> <p>2016-04-01</p> <p>Most of tight-binding studies of transition metal based systems deviating from perfect bulk (surfaces, nanoparticles, alloys) are based on local charge neutrality rules per site, per valence orbital and per element. Unfortunately, such rules do not hold per spin when interested in <span class="hlt">magnetic</span> elements. We present here a simple way to characterize the variation of the <span class="hlt">magnetic</span> moment with the environment and to generalize the tight-binding expression of the energy to account for <span class="hlt">magnetism</span>. This is illustrated in the particular case of cobalt, going from perfect pure bulk to surface, nanoparticles and then CoPt alloy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DMP.U7004K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DMP.U7004K"><span id="translatedtitle">Electromagnetically Induced Absorption (EIA) and a Twist'' on Nonlinear Magneto-optical Rotation (NMOR) with Cold <span class="hlt">Atoms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kunz, Paul; Meyer, David; Quraishi, Qudsia</p> <p>2015-05-01</p> <p>Within the class of nonlinear optical effects that exhibit sub-natural linewidth features, electromagnetically induced transparency (EIT) and nonlinear magneto-optical rotation (NMOR) stand out as having made dramatic impacts on various applications including <span class="hlt">atomic</span> clocks, magnetometry, and single photon storage. A related effect, known as electromagnetically induced absorption (EIA), has received less attention in the literature. Here, we report on the first observation of EIA in cold <span class="hlt">atoms</span> using the Hanle configuration, where a single laser beam is used to both pump and probe the <span class="hlt">atoms</span> while sweeping a <span class="hlt">magnetic</span> field through zero along the beam direction. We find that, associated with the EIA peak, a `twist'' appears in the corresponding NMOR signal. A similar twist has been previously noted by Budker et al., in the context of <span class="hlt">warm</span> vapor optical magnetometry, and was ascribed to optical pumping through nearby hyperfine levels. By studying this feature through numerical simulations and cold <span class="hlt">atom</span> experiments, thus rendering the hyperfine levels well resolved, we enhance the understanding of the optical pumping mechanism behind it, and elucidate its relation to EIA. Finally, we demonstrate a useful application of these studies through a simple and rapid method for nulling background <span class="hlt">magnetic</span> fields within our <span class="hlt">atom</span> chip apparatus.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21513055','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21513055"><span id="translatedtitle">Chameleon induced <span class="hlt">atomic</span> afterglow</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Brax, Philippe; Burrage, Clare</p> <p>2010-11-01</p> <p>The chameleon is a scalar field whose mass depends on the density of its environment. Chameleons are necessarily coupled to matter particles and will excite transitions between <span class="hlt">atomic</span> energy levels in an analogous manner to photons. When created inside an optical cavity by passing a laser beam through a constant <span class="hlt">magnetic</span> field, chameleons are trapped between the cavity walls and form a standing wave. This effect will lead to an afterglow phenomenon even when the laser beam and the <span class="hlt">magnetic</span> field have been turned off, and could be used to probe the interactions of the chameleon field with matter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19810005591','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19810005591"><span id="translatedtitle"><span class="hlt">Atomic</span> hydrogen storage method and apparatus</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Woollam, J. A. (Inventor)</p> <p>1980-01-01</p> <p><span class="hlt">Atomic</span> hydrogen, for use as a fuel or as an explosive, is stored in the presence of a strong <span class="hlt">magnetic</span> field in exfoliated layered compounds such as molybdenum disulfide or an elemental layer material such as graphite. The compounds maintained at liquid helium temperatures and the <span class="hlt">atomic</span> hydrogen is collected on the surfaces of the layered compound which are exposed during delamination (exfoliation). The strong <span class="hlt">magnetic</span> field and the low temperature combine to prevent the <span class="hlt">atoms</span> of hydrogen from recombining to form molecules.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1227666','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1227666"><span id="translatedtitle"><span class="hlt">Warming</span> trends: Adapting to nonlinear change</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jonko, Alexandra K.</p> <p>2015-01-28</p> <p>As atmospheric carbon dioxide concentrations rise, some regions are expected to <span class="hlt">warm</span> more than others. Research suggests that whether <span class="hlt">warming</span> will intensify or slow down over time also depends on location.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26649399','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26649399"><span id="translatedtitle">Trophic mismatch requires seasonal heterogeneity of <span class="hlt">warming</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Straile, Dietmar; Kerimoglu, Onur; Peeters, Frank</p> <p>2015-10-01</p> <p>Climate <span class="hlt">warming</span> has been shown to advance the phenology of species. Asynchronous changes in phenology between interacting species may disrupt feeding interactions (phenological mismatch), which could have tremendous consequences for ecosystem functioning. Long-term field observations have suggested asynchronous shifts in phenology with <span class="hlt">warming</span>, whereas experimental studies have not been conclusive. Using proxy-based modeling of three trophic levels (algae, herbivores, and fish), we .show that asynchronous changes in phenology only occur if <span class="hlt">warming</span> is seasonally heterogeneous, but not if <span class="hlt">warming</span> is constant throughout the year. If <span class="hlt">warming</span> is seasonally heterogeneous, the degree and even direction of asynchrony depends on the specific seasonality of the <span class="hlt">warming</span>. Conclusions about phenological mismatches in food web interactions may therefore produce controversial results if the analyses do not distinguish between seasonally constant and seasonal specific <span class="hlt">warming</span>. Furthermore, our results suggest that predicting asynchrony between interacting species requires reliable <span class="hlt">warming</span> predictions that resolve sub-seasonal time scales. PMID:26649399</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <center> <div class="footer-extlink text-muted"><small>Some links on this page may take you to non-federal websites. 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