Exchange Bias with Interacting Random Anti-ferromagnetic Grains

TL;DR

This paper presents a model of interacting anti-ferromagnetic grains coupled to a ferromagnetic layer to explain exchange bias phenomena, capturing key experimental behaviors and dependencies.

Contribution

It introduces a simple yet effective model that describes exchange bias behavior, including the inverse relationship with grain size and effects of cooling field.

Findings

Exchange bias shifts depend on cooling field and grain size.

Exchange bias field is inversely proportional to grain size.

The model matches several observed behaviors in real materials.

Abstract

A model consisting of random interacting anti-ferromagnetic (AF) grains coupled to a ferromagnetic (FM) layer is developed to study the exchange bias phenomenon. This simple model is able to describe several exchange bias behavior observed in real materials. Shifts in hysteresis loops are observed as a function of cooling field and average grain size. We establish a direct relationship between cooling field dependence of exchange bias, coercivity and magnetization state on the AF-FM interface. We also verify that the exchange bias field is inversely proportional to the grain size, and this behavior is independent of the inter-grain interactions, AF/FM coupling and cooling field.