Crystal structure, incommensurate magnetic order and ferroelectricity in mn$_{1-x}$cu$_{x}$wo${_4}$ (x=0-0.19)

TL;DR

This study investigates how Cu doping affects the magnetic, dielectric, and structural properties of MnWO4, revealing decreased magnetic frustration, stabilized magnetic order, and a potential spin-flop transition, leading to a comprehensive magnetoelectric phase diagram.

Contribution

It provides the first systematic analysis of Cu doping effects on MnWO4's properties using multiple techniques, uncovering new magnetic and dielectric phenomena.

Findings

Cu doping reduces magnetic frustration

Stabilization of commensurate magnetic order

Evidence of a spin-flop transition below 10 K

Abstract

We have carried out a systematic study on the effect of Cu doping on nuclear, magnetic, and dielectric properties in Mn$_{1-x}$Cu$_{x}$WO$_4$ for ${0}\leq{x}\leq{0.19}$ by a synergic use of different techniques, viz, heat capacity, magnetization, dielectric, and neutron powder diffraction measurements. Via heat capacity and magnetization measurements we show that with increasing Cu concentration magnetic frustration decreases, which leads to the stabilization of commensurate magnetic ordering. This was further verified by temperature-dependent unit cell volume changes derived from neutron diffraction measurements which was modeled by the Gr\"{u}neisen approximation. Dielectric measurements show a low temperature phase transition below about 9-10 K. Further more, magnetic refinements reveal no changes below this transition indicating a possible spin-flop transition which is unique to the Cu doped system. From these combined studies we have constructed a magnetoelectric phase diagram of this compound.