Memory devices such as computer hard disks must be able to quickly and reversibly switch the orientation of magnetic domains in their data-storing platter. But switching these domains often requires electromagnets, which consume a relatively large amount of electrical power. Morgan Trassin at the University of California, Berkeley, and his colleagues report that the magnetization of a material can be reversibly switched by the direct application of an electric field, which uses less power.

The team deposited a layer of a cobalt and iron alloy onto a thin film of bismuth ferrite, the magnetic properties of which change with an electric field. Applying an electric field at room temperature altered the polarization of the magnetic domains in the bismuth-based film, which then reversed the magnetization of the alloy.

The authors suggest that this could offer an approach to designing low-power, compact memory devices.

Phys. Rev. Lett. 107, 217202 (2011)