Magnetoresistance switch effect in a multiferroic Fe3O4∕BaTiO3 bilayer

Multiferroic bilayers composed of a magnetite (Fe3O4) and a BaTiO3 layer show nonlinear current-voltage characteristics in current perpendicular to plane configuration. The magnetoresistance of the bilayers is strongly bias dependent and can be switched from negative at low bias to positive at large bias. It is shown that these effects do not arise from charge-carrier modulation in the magnetite layer by an electric field effect. Therefore both the nonlinear transport characteristics and the switchable magnetoresistance are attributed to interfacial transport phenomena.