# Magnetoelectric domains and their switching mechanism in a Y-type hexaferrite

## TL;DR

This study uses resonant X-ray microdiffraction to image and control magnetoelectric domains in a Y-type hexaferrite, revealing limitations of existing models and proposing a modified magnetic structure consistent with experimental data.

## Contribution

The paper introduces a modified model for the polar magnetic structure of Y-type hexaferrite that better fits experimental data and suggests internal magnetic chirality influences domain behavior.

## Key findings

- Magnetic polarity domains can be controlled by magnetic and electric fields.
- Full inversion of domains achieved by magnetic field reversal without electric bias.
- Deviations from the 2-fan transverse conical model suggest internal magnetic chirality.

## Abstract

By employing resonant X-ray microdiffraction, we image the magnetisation and magnetic polarity domains of the Y-type hexaferrite Ba$_{0.5}$Sr$_{1.5}$Mg$_2$Fe$_{12}$O$_{22}$. We show that the magnetic polarity domain structure can be controlled by both magnetic and electric fields, and that full inversion of these domains can be achieved simply by reversal of an applied magnetic field in the absence of an electric field bias. Furthermore, we demonstrate that the diffraction intensity measured in different X-ray polarisation channels cannot be reproduced by the accepted model for the polar magnetic structure, known as the 2-fan transverse conical (TC) model. We propose a modification to this model, which achieves good quantitative agreement with all of our data. We show that the deviations from the TC model are large, and may be the result of an internal magnetic chirality, most likely inherited from the parent helical (non-polar) phase.