Separation of the first- and second-order contributions in magneto-optic Kerr effect magnetometry of epitaxial FeMn/NiFe bilayers

TL;DR

This paper develops a method to separate first- and second-order magneto-optic effects in Kerr magnetometry of FeMn/NiFe bilayers, enabling detailed analysis of magnetization reversal behavior.

Contribution

It introduces a procedure to distinguish and analyze first- and second-order contributions in Kerr effect measurements of exchange-coupled bilayers.

Findings

Successful separation of magneto-optic contributions

Good agreement between experiment and extended Stoner-Wohlfarth model

Detailed angular dependence of magnetization reversal

Abstract

The influence of second-order magneto-optic effects on Kerr effect magnetometry of epitaxial exchange coupled FeMn/NiFe-bilayers is investigated. A procedure for separation of the first- and second-order contributions is presented. The full angular dependence of both contributions during the magnetization reversal is extracted from the experimental data and presented using gray scaled magnetization reversal diagrams. The theoretical description of the investigated system is based on an extended Stoner-Wohlfarth model, which includes an induced unidirectional and fourfold anisotropy in the ferromagnet, caused by the coupling to the antiferromagnet. The agreement between the experimental data and the theoretical model for both the first- and second-order contributions are good, although a coherent reversal of the magnetization is assumed in the model.