Interfacial electronic structure and magnetoelectric effect in M/BaTiO3 (M=Ni,Fe) superlattices

Using first-principles density functional theory, we investigate the interfacial electronic structure and magnetoelectric effect in M/BaTiO₃ (M=Ni, Fe) superlattices, and find a novel type of interfacial magnetoelectric coupling mechanism in the Ni/BaTiO₃ interface. This magnetoelectric effect is determined by the change of magnetic moments on Ni atoms near the interface, instead of the induced moments on interfacial Ti atoms in Fe/BaTiO₃ system, which is also distinguished from the spin-polarized carriers screening mechanism. The underlying physics is the strong interface bonding and the pdσ-type magnetic interactions between Ni 3d and O 2p spins. Furthermore, there exists an extraordinary intralayer oscillation of magnetic moments within the Ni layers, which may be observed in experiments.