Electric Field Switching of the Magnetic Anisotropy of a Ferromagnetic Layer Exchange Coupled to the Multiferroic CompoundBiFeO3

Abstract

We report here that a Permalloy layer deposited on top of a multiferroic ${\mathrm{BiFeO}}_3$ single crystal acquires an easy magnetic direction along the propagation vector of the cycloidal arrangement of antiferromagnetic moments in ${\mathrm{BiFeO}}_3$. This anisotropy originates from a direct magnetic coupling with the canted spins forming the cycloid. Moreover, we show that an electric field-induced change of electric polarization is able to toggle the direction of anisotropy in the ferromagnet through the magnetoelectric effect, which links the antiferromagnetic spins to the local polarization in ${\mathrm{BiFeO}}_3$.