Large voltage-controlled magnetic anisotropy in the SrTiO3/Fe/Cu structure

Abstract

First-principles calculations are performed to investigate the magnetic anisotropy and voltage-controlled magnetic anisotropy (VCMA) in the strontium titanate (SrTiO3)-based structure. It is found that SrTiO3/Fe/Cu gives rise to an interfacial perpendicular magnetic anisotropy (PMA) of 1.3 mJ/m2. More importantly, the VCMA coefficient of this structure is 37% larger than that of the MgO-based counterpart. The microscopic mechanism is elucidated by resolving the VCMA effect to each atomic layer and each orbital hybridization. We demonstrate that the VCMA effect is not confined at the first Fe monolayer of the SrTiO3/Fe interface but extends into the second and third Fe monolayers. The origin of these phenomena can be explained with the changes of contributions to PMA from each orbital hybridization induced by redistributions of orbital occupancy under an electric field.