Control of a polar order via magnetic field in a vector-chiral magnet

TL;DR

This study demonstrates control of ferroelectricity in a vector-chiral magnet through magnetic fields, revealing a novel magnetoelectric coupling mechanism in a frustrated spin chain system.

Contribution

The paper provides direct experimental evidence of ferroelectricity in the VC phase of etaVO, highlighting a new way to manipulate multiferroic properties via magnetic fields.

Findings

Saturation polarization correlates with VC magnetic reflections.

Inverse Dzyaloshinskii-Moriya mechanism drives electric polarization.

Electric coercive field depends on applied magnetic field, enabling control.

Abstract

Vector-chiral (VC) antiferromagnetism is a spiral-like ordering of spins which may allow ferroelectricity to occur due to loss of space inversion symmetry. In this paper we report direct experimental observation of ferroelectricity in the VC phase of $\beta$-TeVO$_4$, a frustrated spin chain system with pronounced magnetic anisotropy and a rich phase diagram. Saturation polarization is proportional to neutron scattering intensities that correspond to the VC magnetic reflection. This implies that inverse Dzyaloshinskii-Moriya mechanism is responsible for driving electric polarization. Linear magnetoelectric coupling is absent, however an unprecedented dependence of electric coercive field on applied magnetic field reveals a novel way of manipulating multiferroic information.