Pressure effects on magnetic ground states in cobalt doped multiferroic Mn$_{1-x}$Co$_{x}$WO$_4$

TL;DR

This study investigates how pressure and cobalt doping influence the structural and magnetic properties of multiferroic Mn$_{1-x}$Co$_x$WO$_4$, revealing different effects at various doping levels and highlighting the roles of magnetic anisotropy and chemical pressure.

Contribution

It provides a comparative analysis of pressure and doping effects on magnetic ground states in Mn$_{1-x}$Co$_x$WO$_4$, emphasizing the dominant influence of magnetic anisotropy at low doping and chemical pressure at high doping.

Findings

Pressure and Co doping both stretch Mn-Mn chains along c.

High doping levels induce a spin-flop transition under pressure.

Magnetic ground states are robust at low doping but change with doping at higher levels.

Abstract

Using ambient pressure x-ray and high pressure neutron diffraction, we studied the pressure effect on structural and magnetic properties of multiferroic Mn$_{1-x}$Co$_x$WO$_4$ single crystals ($x=0, 0.05, 0.135$ and $0.17$), and compared it with the effects of doping. Both Co doping and pressure stretch the Mn-Mn chain along the $c$~direction. At high doping level ($x=0.135$ and $0.17$), pressure and Co doping drive the system in a similar way and induce a spin-flop transition for the $x=0.135$ compound. In contrast, magnetic ground states at lower doping level ($x=0$ and $0.05$) are robust against pressure but experience a pronounced change upon Co substitution. As Co introduces both chemical pressure and magnetic anisotropy into the frustrated magnetic system, our results suggest the magnetic anisotropy is the main driving force for the Co induced phase transitions at low doping level, and chemical pressure plays a more significant role at higher Co concentrations.