Magnetoelectric Devices for Spintronics

The control of magnetism by electric fields is an important goal for the future development of low-power spintronics. Various approaches have been proposed on the basis of either single-phase multiferroic materials or hybrid structures in which a ferromagnet is influenced by the electric field applied to an adjacent insulator (usually having a ferroelectric, piezoelectric, or multiferroic character). The electric field effect on magnetism can be driven by purely electronic or electrostatic effects or can occur through strain coupling. Here we review progress in the electrical control of magnetic properties (anisotropy, spin order, ordering temperature, domain structure) and its application to prototype spintronic devices (spin valves, magnetic tunnel junctions). We tentatively identify the main outstanding difficulties and give perspectives for spintronics and other fields.