Local electrical control of magnetic order and orientation by ferroelastic domain arrangements just above room temperature

Ferroic materials (ferromagnetic, ferroelectric, ferroelastic) usually divide into domains with different orientations of their order parameter. Coupling different ferroic systems creates new functionalities, for instance the electrical control of macroscopic magnetic properties including magnetization and coercive field. Here we show that ferroelastic domains can be used to control both magnetic order and magnetization direction at the nanoscale with a voltage. We use element-specific x-ray imaging to map the magnetic domains as a function of temperature and voltage in epitaxial FeRh on ferroelastic BaTiO3. Exploiting the nanoscale phase-separation of FeRh, we locally interconvert between ferromagnetism and antiferromagnetism with a small electric field just above room temperature. Our results emphasize the importance of nanoscale ferroic domain structure to achieve enhanced coupling in artificial multiferroics.