Enhanced Magnetoelectric Coupling in BaTiO(3)-BiFeO(3) Multilayers—An Interface Effect

Combining various (multi-)ferroic materials into heterostructures is a promising route to enhance their inherent properties, such as the magnetoelectric coupling in BiFeO(3) thin films. We have previously reported on the up-to-tenfold increase of the magnetoelectric voltage coefficient [Formula: see text] in BaTiO(3)-BiFeO(3) multilayers relative to BiFeO(3) single layers. Unraveling the origin and mechanism of this enhanced effect is a prerequisite to designing new materials for the application of magnetoelectric devices. By careful variations in the multilayer design we now present an evaluation of the influences of the BaTiO(3)-BiFeO(3) thickness ratio, oxygen pressure during deposition, and double layer thickness. Our findings suggest an interface driven effect at the core of the magnetoelectric coupling effect in our multilayers superimposed on the inherent magnetoelectric coupling of BiFeO(3) thin films, which leads to a giant [Formula: see text] coefficient of 480 [Formula: see text] [Formula: see text] [Formula: see text] [Formula: see text] Oe [Formula: see text] for a [Formula: see text] (BaTiO(3)-BiFeO(3)) superlattice with a [Formula: see text] nm double layer periodicity.