Magnetic fan structures in Ba$_{0.5}$Sr$_{1.5}$Zn$_2$Fe$_{12}$O$_{22}$ hexaferrite revealed by resonant soft X-ray diffraction

TL;DR

This study uses resonant soft X-ray diffraction to investigate magnetic structures in a hexaferrite, revealing field-induced fan-like phases and a new magnetic phase near phase boundaries.

Contribution

It reports the discovery of a new magnetic phase and details the evolution of magnetic structures under applied magnetic fields in a Y-type hexaferrite.

Findings

Helical spin block transforms into fan-like structure under magnetic field.

Propagation vectors vary with applied field.

A new magnetic phase is identified near phase boundaries.

Abstract

The hexaferrites are known to exhibit a wide range of magnetic structures, some of which are connected to important technological applications and display magnetoelectric properties. We present data on the low field magnetic structures stabilised in a Y-type hexaferrite as observed by resonant soft X-ray diffraction. The helical spin block arrangement that is present in zero applied magnetic field becomes fan-like as a field is applied in plane. The propagation vectors associated with each fan structure are studied as a function of field, and a new magnetic phase is reported. Mean field calculations indicate this phase should stabilise close to the boundary of the previously reported phases.