Observation of Topological Hall Effect in Synthetic Antiferromagnetic Skyrmion System

TL;DR

This paper reports the observation of the topological Hall effect in synthetic antiferromagnetic skyrmion systems, demonstrating their robustness and providing insights into their magnetic interactions, which advances their potential application in spintronics.

Contribution

The study provides the first experimental observation of the topological Hall effect in SAF skyrmions and links it to RKKY coupling and magnetic proximity effects, offering a new detection method.

Findings

Observation of topological Hall effect in SAF skyrmions

Demonstration of skyrmion robustness under zero-field

Insight into magnetic interactions via RKKY coupling

Abstract

Synthetic antiferromagnetic (SAF) skyrmions have emerged as promising candidates for next-generation high-speed and highly integrated spintronic devices, owing to their exceptional properties such as high driving velocity, nanoscale dimensions, and the absence of the skyrmion Hall effect. In this work, we report the observation of the topological Hall effect in both compensated and non-compensated synthetic antiferromagnetic skyrmion systems based on [Pt/Co/Ru]2 bilayers. The antiferromagnetic skyrmions are demonstrated to be robust in these synthetic antiferromagnets under zero-field. Our first principal calculations and micromagnetic simulations demonstrate that the formation of the antiferromagnetic skyrmions are due to nonuniformity of RKKY coupling associated with the proximity effect induced magnetic moments in the Pt and Ru layers. The skyrmions in the Pt and Ru layers adjacent to the Co layers lead to the observed topological Hall effect. This work not only provides insight into the effect of the magnetic proximity effect and RKKY coupling to the SAF skyrmions, but also an effective detection method for the SAF skyrmion systems, thereby laying a foundation for the practical application of antiferromagnetic skyrmions in spintronic devices.