Domain switching and exchange bias control by electric field in multiferroic conical magnet Mn$_2$GeO$_4$

TL;DR

This study demonstrates electric field control of magnetism and exchange bias in multiferroic Mn$_2$GeO$_4$, revealing a rare single-phase multiferroic phenomenon with potential for electric-magnetic device applications.

Contribution

It reports the first observation of electrically controllable exchange bias and non-reversible electric switching of domains in a single-phase multiferroic material.

Findings

Electric fields can modulate magnetic hysteresis and polarization.

Small magnetic fields reduce the electric field needed for saturation.

Electric switching of domains is achievable under specific conditions.

Abstract

The electric field effect on magnetism was examined in the multiferroic conical magnet Mn$_2$GeO$_4$, which shows a strong coupling between ferromagnetic and ferroelectric order parameters. The systematic evaluation of the electric polarization in the multiferroic phase below 5.5 K under various field cooling conditions reveals that small magnetic fields of 0.1 T significantly reduce the required electric fields needed to reach saturation. By applying electric fields during magnetic field dependent hysteresis measurements of magnetization M and polarization P an electrically controllable exchange bias was observed, a phenomenon exceedingly rare in single phase multiferroics. Furthermore, non-reversible electric switching of P and M domains was achieved under specific magnetic field conditions.