Exchange Bias driven by Dzyaloshinskii-Moriya interactions

TL;DR

This study investigates the origin of exchange bias in IrMn3/Co bilayers, revealing that Dzyaloshinskii-Moriya interactions primarily induce the bias, with coercivity enhancement linked to a spin-flop mechanism, through multiscale modeling.

Contribution

It demonstrates that Dzyaloshinskii-Moriya interactions are the main cause of exchange bias in IrMn3/Co systems, combining ab initio and atomistic modeling approaches.

Findings

Perpendicular exchange bias field observed.

Coercivity increases due to spin-flop mechanism.

Dzyaloshinskii-Moriya interactions are the primary origin of exchange bias.

Abstract

The exchange bias effect in compensated IrMn3/Co(111) system is studied using multiscale modeling from "ab initio" to atomistic calculations. We evaluate numerically the out-of-plane hysteresis loops of the bi-layer for different thickness of the ferromagnetic layer. The results show the existence of a perpendicular exchange bias field and an enhancement of the coercivity of the system. In order to elucidate the possible origin of the exchange bias, we analyze the hysteresis loops of a selected bi-layer by tuning the different contributions to the exchange interactions across the interface. Our results indicate that the exchange bias is primarily induced by the Dzyaloshinskii-Moriya interactions, while the coercivity is increased mainly due to a spin-flop mechanism.