Multiferroic magnetoelectrics are materials that are both ferromagnetic and ferroelectric in the same phase. As a result they have a spontaneous magnetization which can be switched by an applied magnetic field, a spontaneous polarization which can be switched by an applied electric field, and often some coupling between the two. Very few exist in nature, or have been synthesized in the laboratory, but there is some incentive to produce new multiferroics for technological applications.
In this talk we use the study of multiferroics to illustrate the utility of theoretical and computational methods in the design of new multifunctional materials. First we determine the fundamental physics behind the scarcity of ferromagnetic ferroelectric coexistence, and show that in general transition metal d electrons, which are essential for magnetism, reduce the tendency for off-center ferroelectric distortion. Then we identify the chemistry behind the additional electronic or structural driving forces that must be present for ferromagnetism and ferroelectricity to occur simultaneously. Finally we describe the successful prediction and subsequent synthesis of new multiferroic materials.
Hosts: John Wei and Young-June Kim