# On the nature of spin reorientation transition thermal hysteresis in NiO(111)/Fe(110) bilayers

## TL;DR

The paper studies how magnetization switches in a NiO/Fe bilayer as temperature changes, revealing a thermal hysteresis effect.

## Contribution

The study reveals a temperature-driven spin reorientation transition with thermal hysteresis in NiO(111)/Fe(110) bilayers.

## Key findings

- A 90° in-plane magnetization switching occurs with temperature changes in the NiO/Fe bilayer.
- Thermal hysteresis between 210–285 K shows coexisting energy minima at specific temperatures.
- Phenomenological modeling confirms the role of magnetic anisotropies in stabilizing magnetization orientations.

## Abstract

We report on temperature-driven in-plane 90° magnetization switching in NiO(111)/Fe(110) bilayer epitaxially grown on a W(110) single crystal, investigated using magneto-optical Kerr effect and X-ray magnetic circular and linear dichroism measurements. As the temperature varies, an abrupt switching of the easy axis between the in-plane Fe[001] and Fe\documentclass[12pt]{minimal}
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\begin{document}$$\left[ {1\overline{{{\text{1}}}} 0} \right]$$\end{document} crystallographic directions is observed. In the temperature range of approximately 210–285 K, a thermal hysteresis region appears, where two energy minima coexist at a given temperature. Our experimental findings are supported by phenomenological modeling. Simulations incorporating temperature-dependent anisotropy constants successfully reproduce the key features of the observed phenomenon, most notably the temperature-driven hysteresis of ferromagnetic magnetization switching. The spin reorientation transition in both exchange-coupled ferromagnetic and antiferromagnetic layers is driven by the interplay between magnetocrystalline and interfacial magnetic anisotropies in the ferromagnet, which stabilizes specific magnetization orientation at given temperature.

The online version contains supplementary material available at 10.1038/s41598-025-07541-1.