Magnetic switching and phase competition in the multiferroic antiferromagnet $\rm Mn_{1-x}Fe_xWO_4$

TL;DR

This study investigates how Fe doping and magnetic fields influence magnetic phases and ferroelectricity in the multiferroic MnWO_4, revealing tunable phase competition and the suppression or restoration of incommensurate magnetic order.

Contribution

It provides new insights into the control of magnetic and ferroelectric phases in MnWO_4 through Fe doping and magnetic fields, highlighting the role of competing interactions.

Findings

Incommensurate magnetic order is suppressed with Fe doping.

Magnetic field can restore the incommensurate phase.

Fe doping extends the low-temperature commensurate magnetic structure.

Abstract

Elastic neutron scattering is used to study the spin correlations in the multiferroic $\rm Mn_{1-x}Fe_{x}WO_4$ with $x=0.035, 0.05$ and 0.10. The noncollinear, incommensurate (ICM) magnetic structure associated with the ferroelectric (FE) phase in pure $\rm MnWO_4$ is suppressed at $x=0.035$ and completely absent at $x=0.10$. The ICM spin order and FE phase can be restored by applying a magnetic field along the spin easy-axis. The low-$T$ commensurate magnetic structure extends in both H/T with increasing Fe concentration. The systematic evolution of the magnetic and electric properties indicates that the noncollinear ICM spin order results from competing magnetic interactions and its stabilization can be tuned by the internal ($x$) or external (magnetic field) perturbations.