Ferroelectric control of magnetism in Pt/BaTiO₃ thin films

The quest for artificial multiferroic heterostructures consisting of ferroelectric (FE) and ferromagnetic (FM) layers are of increasing interest. Because the optimizing interfacial magnetoelectric coupling between the magnetic and electric polarizations allows novel means of controlling magnetization or polarization in view of efficient, low-power spintronic devices. Using first principles calculations we predict the emergence of magnetism in ultrathin nonmagnetic Pt films induced by the ferroelectric polarization of BaTiO₃ films, where the induced Pt magnetization depends on the polarization direction. More importantly, the calculations reveal that the Pt/BatiO₃ bilayer undergoes an in-plane to out-of-plane spin reorientation via ferroelectric polarization switching of the BTO, with a giant change of magnetic anisotropy from 1.15 to -0.49 erg/cm², indicating a huge magnetoelectric effect. These findings open interesting prospects for exploiting higher electric field efficiency of magnetic anisotropy for the next generation of magnetoelectric random access memory devices.