Electric-field switching of perpendicularly magnetized multilayers

Perpendicularly magnetized layers are used widely for high-density information storage in magnetic hard disk drives and nonvolatile magnetic random access memories. Writing and erasing of information in these devices is implemented by magnetization switching in local magnetic fields or via intense pulses of electric current. Improvements in energy efficiency could be obtained when the reorientation of perpendicular magnetization is controlled by an electric field. Here, we report on reversible electric-field-driven out-of-plane to in-plane magnetization switching in Cu/Ni multilayers on ferroelectric BaTiO3 at room temperature. Fully deterministic magnetic switching in this hybrid material system is based on efficient strain transfer from ferroelastic domains in BaTiO3 and the high sensitivity of perpendicular magnetic anisotropy in Cu/Ni to electric-field-induced strain modulations. We also demonstrate that the magnetoelectric coupling effect can be used to realize 180 degrees magnetization reversal if the out-of-plane symmetry of magnetic anisotropy is temporarily broken by a small magnetic field.