Electric-field control of local ferromagnetism using a magnetoelectric multiferroic

Multiferroics are of interest for memory and logic device applications, as the coupling between ferroelectric and magnetic properties enables the dynamic interaction between these order parameters. Here, we report an approach to control and switch local ferromagnetism with an electric field using multiferroics. We use two types of electromagnetic coupling phenomenon that are manifested in heterostructures consisting of a ferromagnet in intimate contact with the multiferroic BiFeO 3 . The first is an internal, magnetoelectric coupling between antiferromagnetism and ferroelectricity in the BiFeO 3 film that leads to electric-field control of the antiferromagnetic order. The second is based on exchange interactions at the interface between a ferromagnet (Co 0.9 Fe 0.1 ) and the antiferromagnet. We have discovered a one-to-one mapping of the ferroelectric and ferromagnetic domains, mediated by the colinear coupling between the magnetization in the ferromagnet and the projection of the antiferromagnetic order in the multiferroic. Our preliminary experiments reveal the possibility to locally control ferromagnetism with an electric field. Multiferroic materials are of interest because they allow control of their magnetic properties through electric fields. However, room-temperature magnetoelectrics often show antiferromagnetic order, reducing the effects of such coupling. A novel approach demonstrates switchable electric field control over a local magnetic field through the indirect route of exchange bias.