Robust Ferroelectric State in Multiferroic Mn$_{1-x}$Zn$_x$WO$_4$

TL;DR

This study demonstrates that the multiferroic Mn$_{1-x}$Zn$_x$WO$_4$ maintains a robust ferroelectric state even with high levels of Zn substitution, revealing stability of magnetic and ferroelectric phases.

Contribution

It provides new insights into the stability of multiferroic states under chemical substitution, showing ferroelectricity persists up to 50% Zn doping.

Findings

Ferroelectric state remains stable with over 50% Zn substitution.

Complete suppression of low-temperature paraelectric phase at 5% Zn.

Ferroelectric polarization correlates with incommensurate magnetic peak intensity.

Abstract

We report the remarkably robust ferroelectric state in the multiferroic compound Mn$_{1-x}$Zn$_x$WO$_4$. The substitution of the magnetic Mn$^{2+}$ with nonmagnetic Zn$^{2+}$ reduces the magnetic exchange and provides control of the various magnetic and multiferroic states of MnWO$_4$. Only 5 % of Zn substitution results in a complete suppression of the frustrated collinear (paraelectric) low temperature phase. The helical magnetic and ferroelectric phase develops as the ground state. The multiferroic state is stable up to a high level of substitution of more than 50 %. The magnetic, thermodynamic, and dielectric properties as well as the ferroelectric polarization of single crystals of Mn$_{1-x}$Zn$_x$WO$_4$ are studied for different substitutions up to x=0.5. The magnetic phases have been identified in single crystal neutron scattering experiments. The ferroelectric polarization scales with the neutron intensity of the incommensurate peak of the helical phase.