Metastable Random Field Ising model with exchange enhancement: a simple model for Exchange Bias

TL;DR

This paper introduces a modified random field Ising model with enhanced exchange interactions to replicate hysteresis loops exhibiting exchange bias, providing a simple framework to analyze the effects of disorder and exchange enhancement.

Contribution

It presents a novel simple model incorporating exchange enhancement to study exchange bias phenomena in hysteresis loops.

Findings

The model successfully reproduces hysteresis loops with exchange bias.

Exchange bias depends on the fraction of enhanced bonds and disorder parameters.

The model allows analysis of how exchange enhancement influences magnetic properties.

Abstract

We present a simple model that allows hysteresis loops with exchange bias to be reproduced. The model is a modification of the T=0 random field Ising model driven by an external field and with synchronous local relaxation dynamics. The main novelty of the model is that a certain fraction f of the exchange constants between neighbouring spins is enhanced to a very large value J_E. The model allows the dependence of the exchange bias and other properties of the hysteresis loops to be analyzed as a function of the parameters of the model: the fraction f of enhanced bonds, the amount of the enhancement J_E and the amount of disorder which is controlled by the width sigma of the Gaussian distribution of the random fields.