Micromagnetic modelling and imaging of vortex|merons structures in an oxide|metal heterostructure

TL;DR

This study uses micromagnetic simulations to model and identify vortex|meron structures in oxide|metal heterostructures, providing insights into their formation, stabilization, and experimental imaging signatures.

Contribution

It introduces a detailed micromagnetic model for vortex|meron formation in cobalt overlayers stabilized by antiferromagnetic vortices, aligning simulations with experimental observations.

Findings

Simulated meron|antimeron structures match experimental images.

Surface roughness does not prevent meron|antimeron stabilization.

Distinct imaging signatures identified for experimental detection.

Abstract

Using micromagnetic simulations, we have modelled the formation of imprinted merons and anti-merons in cobalt overlayers of different thickness (1-8 nm), stabilised by interfacial exchange with antiferromagnetic vortices in $\alpha$-Fe2O3. Structures similar to those observed experimentally could be obtained with reasonable exchange parameters, also in the presence of surface roughness. We produce simulated meron|antimeron images by magnetic force microscopy (MFM) and nitrogen-vacancy (N-V) centre microscopy, and established signatures of these topological structures in different experimental configurations.