Magnetoelectric coupling at the interface of BiFeO3/La0.7Sr0.3MnO3 multilayers

TL;DR

This paper presents a microscopic model explaining the magnetoelectric coupling at the BiFeO3/La0.7Sr0.3MnO3 interface, highlighting how ferroelectric polarization influences interfacial magnetic properties.

Contribution

It introduces a microscopic Hamiltonian model that explains the origin of magnetoelectric coupling at the interface, aligning with experimental observations.

Findings

Net ferromagnetic moment at the BiFeO3 interface

Interfacial charge density controls magnetic tendencies

Balance between double exchange and superexchange explains coupling

Abstract

Electric-field controlled exchange bias in a heterostructure composed of the ferromagnetic manganite La0.7Sr0.3MO3 and the ferroelectric antiferromagnetic BiFeO3 has recently been demonstrated experimentally. By means of a microscopic model Hamiltonian we provide a possible explanation of the origin of this magnetoelectric coupling. We find, in agreement with experimental results, a net ferromagnetic moment at the BiFeO3 interface. The induced ferromagnetic moment is the result of the competition between the e_g-electrons double exchange and the t_2g-spins antiferromagnetic superexchange that dominate in bulk BiFeO3. The balance of these simultaneous ferromagnetic and antiferromagnetic tendencies is strongly affected by the interfacial electronic charge density which, in turn, can be controlled by the BiFeO3 ferroelectric polarization.