Asymmetric Reversal in Inhomogeneous Magnetic Heterostructures

TL;DR

This paper investigates asymmetric magnetization reversal in AF/FM bilayers, revealing that intrinsic broken symmetry and inhomogeneous interfacial moments cause local incomplete domain walls, confirmed by experiments and simulations.

Contribution

It introduces a combined experimental and simulation study showing how inhomogeneous interfacial moments lead to asymmetric reversal in magnetic heterostructures.

Findings

Asymmetric reversal is due to intrinsic broken symmetry.

Depth-dependent domain walls are confirmed by Kerr effect.

Simulation results align with experimental observations.

Abstract

Asymmetric magnetization reversal is an unusual phenomenon in antiferromagnet / ferromagnet (AF/FM) exchange biased bilayers. We investigated this phenomenon in a simple model system experimentally and by simulation assuming inhomogeneously distributed interfacial AF moments. The results suggest that the observed asymmetry originates from the intrinsic broken symmetry of the system, which results in local incomplete domain walls parallel to the interface in reversal to negative saturation of the FM. Magneto-optic Kerr effect unambiguously confirms such an asymmetric reversal and a depth-dependent FM domain wall in accord with the magnetometry and simulations.