The Suppression and Recovery of the Ferroelectric Phase in Multiferroic $MnWO_4$

TL;DR

This study demonstrates the complete suppression and subsequent magnetic-field-induced recovery of ferroelectricity in Fe-doped MnWO4, revealing complex magnetic interactions and phase behavior.

Contribution

It reports the first observation of ferroelectric suppression and recovery in MnWO4 through Fe doping and magnetic fields, supported by a mean field model.

Findings

Ferroelectricity is suppressed by 10% Fe substitution in MnWO4.

External magnetic fields restore ferroelectricity in Fe-doped MnWO4.

Magnetic/ferroelectric phase diagram constructed from multiple measurements.

Abstract

We report the discovery of a complete suppression of ferroelectricity in $MnWO_4$ by 10 % iron substitution and its restoration in external magnetic fields. The spontaneous polarization in $Mn_{0.9}Fe_{0.1}WO_4$ arises below 12 K in external fields above 4 T. The magnetic/ferroelectric phase diagram is constructed from the anomalies of the dielectric constant, polarization, magnetization, and heat capacity. The observations are qualitatively described by a mean field model with competing interactions and strong anisotropy. We propose that the magnetic field induces a non-collinear inversion symmetry breaking magnetic structure in $Mn_{0.9}Fe_{0.1}WO_4$.