Micromagnetic approach to exchange bias---A new look at an old problem

TL;DR

This paper introduces a micromagnetic approach to analyze exchange bias in FM/AFM thin films, providing a clearer separation of effects and estimating the maximum possible exchange bias field.

Contribution

It presents a novel micromagnetic framework for exchange bias that isolates interfacial effects and estimates the upper limit of the exchange bias field in real systems.

Findings

Provides a micromagnetic expression for $H_{EB}$ based on exchange length

Improves understanding of FM/AFM interfacial coupling effects

Estimates the maximum exchange bias field achievable

Abstract

We present a micromagnetic approach to exchange bias (EB) in ferromagnetic (FM)/antiferromagnetic (AFM) thin film systems with a small number of irreversible interfacial magnetic moments. We express the exchange bias field $H_{EB}$ in terms of fundamental micromagnetic length scale---the exchange length $l_{ex}$. The benefit from this approach is a better separation of a term related to FM layer from a term related to FM/AFM coupling at interfaces. Using this approach we estimate the highest limit of $H_{EB}$ in real FM/AFM systems.