Enhancing interfacial magnetization with a ferroelectric

Abstract

Ferroelectric control of the electronic and magnetic properties of a correlated oxide provides new opportunities for fundamental science and practical device applications. However, the exploding interest in ferroelectric control of magnetic interfaces, which typically happens in a few nanometers, has been inhibited by the lack of appropriate characterization techniques. Here, the authors have used polarized neutron reflectivity (PNR), a nondestructive yet powerful technique, to directly probe the evolution of the interfacial magnetism at the interface between ferromagnetic La${}_{0.8}$Sr${}_{0.2}$MnO${}_{3}$ and ferroelectric PbZr${}_{0.2}$Ti${}_{0.8}$O${}_{3}$. Using PNR, the authors find that the orientation of the ferroelectric polarization of the ferroelectric layer critically determines the interfacial magnetism, which occurs within a few nanometers of the interface. When the polarization is oriented towards the manganite layer, it is capable of enhancing the interfacial magnetization above the bulk region of the film. This finding not only proves the ferroelectric field effect control of magnetism, but also emphasizes the necessity of separating bulk properties from interfacial phenomena in magnetoelectric materials.