Electric-field switchable magnetization via the Dzyaloshinskii-Moriya interaction: FeTiO_3 versus BiFeO_3

TL;DR

This paper reviews how electric polarization can control magnetization through the Dzyaloshinskii-Moriya interaction, highlighting differences between FeTiO3 and BiFeO3, and exploring symmetry conditions for electric-field switchable magnetization.

Contribution

It identifies the symmetry conditions enabling electric-field switchable magnetization via the Dzyaloshinskii-Moriya interaction in certain multiferroics.

Findings

FeTiO3 allows for electric-field switchable magnetization due to specific symmetry properties.

BiFeO3 does not support this coupling because of its different symmetry.

A symmetry-based framework for ferroelectrically-induced weak ferromagnetism is developed.

Abstract

In this article we review and discuss a mechanism for coupling between electric polarization and magnetization that can ultimately lead to electric-field switchable magnetization. The basic idea is that a ferroelectric distortion in an antiferromagnetic material can "switch on" the Dzyaloshinskii-Moriya interaction which leads to a canting of the antiferromagnetic sublattice magnetizations, and thus to a net magnetization. This magnetization M is coupled to the polarization P via a trilinear free energy contribution of the form P(M x L), where L is the antiferromagnetic order parameter. In particular, we discuss why such an invariant is present in R3c FeTiO_3 but not in the isostructural multiferroic BiFeO_3. Finally, we construct symmetry groups that in general allow for this kind of ferroelectrically-induced weak ferromagnetism.