TEM and STEM were performed using an FEI Tecnai G2 F20 X-TWIN at 200 kV. UV-vis absorbance spectrum was collected with an Ocean Optics spectrometer. For magnetic studies, CTAC-Au@NiB and CTAC-Au@CoB particles were massed using a microbalance and dried on a Si wafer. The Si wafer with the dried nanoparticles was loaded into a straw for bulk magnetometry measurement. The magnetic response of the nanoparticles was measured by SQUID Magnetometry, using a Quantum Design Evercool Magnetic Property Measurement System with the Reciprocating Sample Option (RSO). A Mao-type symmetric diamond anvil cell was used to conduct high pressure experiments. The diamond culet was 300 µm in size and Re gasket with 150 um hole was used as the sample chamber. The sample was dried out on a silicon wafer and then a small piece of the sample was loaded into diamond anvil cell using a needle. Ruby was used as a pressure calibrant . Neon gas was loaded as the pressure medium for quasihydrostatic measurements. In-situ X-ray diffraction experiments were conducted at the Advanced Photon Source, Argonne National Lab beamline 16-BMD. An X-ray beam with a wavelength of 0.2952 Å and Mar image plate detector with an exposure time of 300 s were used for diffraction. For ambient pressure X-ray diffraction, the dried sample was transferred onto a 30 μm thick Kapton tape. Kapton tape background scattering was subtracted from the sample diffraction data. Radial integration was performed using the software DIOPTAS and peak fitting was performed using a combination of Gaussian and Lorentzian peak profiles for further analysis.