Exchange bias in a core/shell magnetic nanoparticle: Monte Carlo simulation

TL;DR

This study uses Monte Carlo simulations to analyze how core size, shell thickness, temperature, and random fields influence exchange bias in ferromagnetic core/antiferromagnetic shell nanoparticles, revealing high sensitivity to core radius.

Contribution

It provides detailed insights into the dependence of exchange bias on structural and thermal parameters in core/shell nanoparticles, highlighting the role of interface spin configurations.

Findings

Exchange bias varies significantly with core radius and shell thickness.

Increasing shell thickness enhances exchange bias.

Higher temperature and random fields decrease exchange bias.

Abstract

By using Monte Carlo simulation on a ferromagnetic core/antiferromagnetic shell nanoparticle, we investigate in details the exchange bias of the magnetic hysteresis as a function of both core radius and shell thickness, at low temperature. It is found that the exchange bias is very sensitive to the core radius and a small variation of the radius may lead to a big fluctuation of the bias. In a general tendency the exchange bias is enhanced by increasing shell thickness and decreasing core radius. The intrinsic correlation between the exchange bias and the spin configuration on the core-shell interface is demonstrated. We further investigate the dependence of the exchange bias on temperature and random field inside the nanoparticle, indicating a monotonous decreasing of the bias with the magnitude of random field and temperature, respectively.