Monte Carlo simulation study of exchange biased hysteresis loops in nanoparticles

TL;DR

This study uses Monte Carlo simulations to investigate exchange bias effects in nanoparticles with a ferromagnetic core and antiferromagnetic shell, revealing the role of interface magnetization in loop shifts.

Contribution

The paper introduces a Monte Carlo simulation model that explains the origin of exchange bias in core-shell nanoparticles by analyzing interface magnetization.

Findings

Exchange bias effects are observed in simulated hysteresis loops.

Interface magnetization contributes to loop shifts.

Thermal dependence of shell and interface magnetizations explains bias.

Abstract

We present the results of Monte Carlo simulations of the magnetic properties of a model for a single nanoparticle consisting in a ferromagnetic core surrounded by an antiferromagnetic shell. The simulations of hysteresis loops after cooling in a magnetic field display exchange bias effects. In order to understand the origin of the loop shifts, we have studied the thermal dependence of the shell and interface magnetizations under field cooling. These results, together with inspection of the snapshots of the configurations attained at low temperature, show the existence of a net magnetization at the interface which is responsible for the bias of the hysteresis loops.