Asymmetric magnetization reversal in the exchange bias system Fe/FeF_2 studied by MOKE

TL;DR

This study investigates the asymmetric magnetization reversal in Fe/FeF2 exchange bias systems using MOKE, revealing how unidirectional anisotropy influences the process and can be modeled with energy calculations.

Contribution

It demonstrates the origin of asymmetric reversal from unidirectional anisotropy and models it through a simple energy density calculation.

Findings

Different transverse magnetization loops depend on field direction.

Asymmetry arises from unidirectional anisotropy.

Reversal can be simulated with energy density including anisotropies.

Abstract

The asymmetry of the magnetization reversal process in exchange biased Fe/FeF$_2$ has been studied by magneto-optical Kerr effect. Qualitatively different transverse magnetization loops are observed for different directions of the cooling and the measuring field. These loops can be simulated by a simple calculation of the total energy density which includes the relevant magnetic anisotropies and coherent magnetization rotation only. Asymmetric magnetization reversal is shown to originate from the unidirectional anisotropy and may be observed if the external measuring field is not collinear with either the exchange bias or the easy axis of the antiferromagnetic epitaxial FeF$_2$(110) layer.