Electric field control of multiferroic domains in Ni$_3$V$_2$O$_8$ imaged by X-ray polarization enhanced topography

TL;DR

This study uses advanced X-ray techniques to investigate and image the magnetic and ferroelectric domain switching in Ni$_3$V$_2$O$_8$, revealing detailed magnetic structures and domain behavior under electric fields.

Contribution

It introduces a novel X-ray polarization enhanced topography method for imaging multiferroic domains and provides new insights into the magnetic structure during ferroelectric phase transition.

Findings

Magnetic moments on 'cross-tie' sites are quenched in the ferroelectric phase.

Ferroelectricity onset is mainly associated with spine site magnetic order.

Domains can be imaged and their gradual switching observed under electric field cycling.

Abstract

The magnetic structure of multiferroic Ni$_3$V$_2$O$_8$ has been investigated using non-resonant X-ray magnetic scattering. Incident circularly polarized X-rays combined with full polarization analysis of the scattered beam is shown to yield high sensitivity to the components of the cycloidal magnetic order, including their relative phases. New information on the magnetic structure in the ferroelectric phase is obtained, where it is found that the magnetic moments on the "cross-tie" sites are quenched relative to those on the "spine" sites. This implies that the onset of ferroelectricity is associated mainly with spine site magnetic order. We also demonstrate that our technique enables the imaging of multiferroic domains through polarization enhanced topography. This approach is used to image the domains as the sample is cycled by an electric field through its hysteresis loop, revealing the gradual switching of domains without nucleation.