Magneto-electric Coupling in Domain Engineered Multiferroic Thin Film Heterostructures.

摘要

Epitaxial BiFeO3 (BFO) thin films have potential for designing novel magneto-electric devices if their unrivaled room-temperature multiferroic properties can be exploited in exchange-coupling. Until now, the fundamental problem in implementing these devices is that exchange interactions between BFO and a ferromagnetic overlayer have been observed only in the presence of domain walls that are also responsible for high leakage currents during electrical poling of the BFO. We have new evidence that the existence of an intrinsic exchange interaction between BFO and a cobalt overlayer that is not mediated by domain walls, and that provides an alternative solution the implementation of these devices. The intrinsic exchange coupling relies on the use of monodomain BFO films, and has shown the capability to rotate the magnetization of a cobalt overlayer by switching the electrical polarization of BFO.