Stability and dynamics of magnetic skyrmions in FM/AFM heterostructures

TL;DR

This paper models skyrmions in FM/AFM heterostructures, showing how layered configurations improve stability and suppress the skyrmion Hall effect, advancing potential spintronic device applications.

Contribution

It introduces a multi-layer model demonstrating enhanced skyrmion stability and suppressed Hall effect, providing new pathways for skyrmion-based device development.

Findings

Exchange bias stabilizes skyrmions better than magnetic fields.

Stacked FM layers with AFM layers suppress skyrmion Hall effect.

High-velocity AFM-coupled skyrmion transport achieved.

Abstract

Magnetic skyrmions have garnered attention for their potential roles in spintronic applications, such as information carriers in computation, data storage, and nano-oscillators due to their small size, topological stability, and the requirement of small electric currents to manipulate them. Two key challenges in harnessing skyrmions are the stabilization requirement through a strong out-of-plane field, and the skyrmion Hall effect (SkHE). Here, we present a systematic model study of skyrmions in FM/AFM multi-layer structures by employing both atomistic Monte Carlo and atomistic spin dynamics simulations. We demonstrate that skyrmions stabilized by exchange bias have superior stability than field-stabilized skyrmions due to the formation of a magnetic imprint within the AFM layer. Additionally, stacking two skyrmion hosting FM layers between two antiferromagnetic (AFM) layers suppresses the SkHE and enables the transport of AFM-coupled skyrmions with high velocity in the order of a few Km/s. This proposed multi-layer configuration could serve as a pathway to overcome existing limitations in the development of skyrmion-based devices, and the insights obtained through this study contribute significantly to the broader understanding of topological spin textures in magnetic materials.