BaNiF4: an electric field-switchable weak antiferromagnet

TL;DR

This paper demonstrates that in BaNiF4, the Dzyaloshinskii-Moriya interaction causes a small canting of magnetic moments, which can be reversed by an electric field, enabling electric control of magnetic order.

Contribution

It reveals a coupling mechanism between ferroelectric polarization and magnetic order via the Dzyaloshinskii-Moriya interaction in BaNiF4.

Findings

Identification of weak antiferromagnetic order parameter in BaNiF4.

Reversible magnetic canting controlled by electric polarization.

Potential for electric field-switchable magnetic devices.

Abstract

We show that in the antiferromagnetic ferroelectric BaNiF4 the Dzyaloshinskii-Moriya interaction leads to a small canting of the magnetic moments, away from the easy axis, resulting in a noncollinear magnetic structure. The canting corresponds to an additional "weak" antiferromagnetic order parameter whose orientation is determined by the polar structural distortion and can be reversed by switching the ferroelectric polarization with an electric field. Our results point the way to a more general coupling mechanism between structural distortions and magnetic order parameters in magnetoelectric multiferroics which can be exploited in the design of electric field-switchable magnets.