Ab Initio Study of the Intrinsic Exchange Bias at the SrRuO$_3$/SrMnO$_3$ Interface

TL;DR

This study uses density-functional calculations to verify two proposed mechanisms for intrinsic exchange bias in oxide heterostructures, specifically at the SrRuO3/SrMnO3 interface, supporting the roles of spin-orbit coupling and ferroelectric polarization.

Contribution

It provides the first ab initio verification that both Dzyaloshinskii-Moriya interaction and ferroelectric polarization can induce exchange bias in oxide interfaces.

Findings

Supports the Dzyaloshinskii-Moriya interaction as a mechanism for exchange bias.

Confirms ferroelectric polarization can induce exchange bias in multiferroic heterostructures.

Provides a computational framework for studying exchange bias mechanisms.

Abstract

In a recent publication (S. Dong et al., Phys. Rev. Lett.103, 127201 (2009)), two (related) mechanisms were proposed to understand the intrinsic exchange bias present in oxides heterostructures involving G-type antiferromagnetic perovskites. The first mechanism is driven by the Dzyaloshinskii-Moriya interaction, which is a spin-orbit coupling effect. The second is induced by the ferroelectric polarization, and it is only active in heterostructures involving multiferroics. Using the SrRuO$_3$/SrMnO$_3$ superlattice as a model system, density-functional calculations are here performed to verify the two proposals. This proof-of-principle calculation provides convincing evidence that qualitatively supports both proposals.