Metglass/PVDF/Metglass trilayer structures. Recently an interesting layer-by-layer growth of an atomic-scale multiferroic composite has been demonstrated, consisting of individual layers of ferroelectric and antiferromagnetic LuFeO3 alternating with ferrimagnetic but non-polar LuFe2O4 in a superlattice. A new promising approach are core-shell type ceramics where a magnetoelectric composite is formed in-situ during synthesis. In the system (BiFe0.9Co0.1O3)0.4-(Bi1/2K1/2TiO3)0.6 (BFC-BKT) very strong ME coupling has been observed on a microscopic scale using PFM under magnetic field. Furthermore, switching of magnetization via electric field has been observed using MFM. Here, the ME active core-shell grains consist of magnetic CoFe2O4 (CFO) cores and a (BiFeO3)0.6-(Bi1/2K1/2TiO3)0.4 (BFO-BKT) shell where core and shell have an epitaxial lattice structure. The mechanism of strong ME coupling is via magnetic exchange interaction between CFO and BFO across the core-shell interface, which results in an exceptionally high Neel-Temperature of 670 K of the BF-BKT phase. Other There have been reports of large magnetoelectric coupling at room-temperature in type-I multiferroics such as in the "diluted" magnetic perovskite (PbZr0.53Ti0.47O3)0.6–(PbFe1/2Ta1/2O3)0.4 (PZTFT) in certain Aurivillius phases. Here, strong ME coupling has been observed on a microscopic scale using PFM under magnetic field among other techniques. Organic-inorganic hybrid multiferroics have been reported in the family of metal-formate perovskites, as well as molecular multiferroics such as [(CH3)2NH2][Ni(HCOO)3], with elastic strain-mediated coupling between the order parameters. Classification Type-I and type-II multiferroics A helpful classification scheme for multiferroics into so-called type-I and type-II multiferroics was introduced in 2009 by D. Khomskii. Khomskii suggested the term type-I multiferroic for materials in which the ferroelectricity and magnetism occur at different temperatures and arise from different mechanisms. Usually the structural distortion which gives rise to the ferroelectricity occurs at high temperature, and the magnetic ordering, which is usually antiferromagnetic, sets in at lower temperature. The prototypical example is BiFeO3 (TC=1100 K, TN=643 K), with the ferroelectricity driven by the stereochemically active lone pair of the Bi3+ ion and the magnetic ordering caused by the usual superexchange mechanism. YMnO3 (TC=914 K, TN=76 K) is also type-I, although its ferroelectricity is so-called "improper", meaning that it is a secondary effect arising from another (primary) structural distortion. The independent emergence of magnetism and ferroelectricity means that the domains of the two properties can exist independently of each other. Most type-I multiferroics show a linear magnetoelectric response, as well as changes in dielectric susceptibility at the magnetic phase transition. The term type-II multiferroic is used for materials