Origin of Electric Field Induced Magnetization in Multiferroic HoMnO3

TL;DR

This study investigates how electric fields influence magnetization in HoMnO3, revealing that electric fields suppress magnetic scattering by affecting antiferromagnetic domain walls rather than the bulk magnetic order.

Contribution

The paper demonstrates that electric fields modulate magnetization in HoMnO3 through domain wall effects, providing new insights into multiferroic coupling mechanisms.

Findings

Magnetic scattering increases below 40 K due to domain wall magnetization.

Electric field suppresses magnetic scattering below 50 K.

Magnetization change is linked to domain walls, not bulk order.

Abstract

We have performed polarized and unpolarized small angle neutron scattering experiments on single crystals of HoMnO3 and have found that an increase in magnetic scattering at low momentum transfers begins upon cooling through temperatures close to the spin reorientation transition at TSR ~ 40 K. We attribute the increase to an uncompensated magnetization arising within antiferromagnetic domain walls. Polarized neutron scattering experiments performed while applying an electric field show that the field suppresses magnetic scattering below T ~ 50 K, indicating that the electric field affects the magnetization via the antiferromagnetic domain walls rather than through a change to the bulk magnetic order.