Visualizing the strongly reshaped skyrmion Hall effect in multilayer wire devices

TL;DR

This study investigates the complex dynamics of magnetic skyrmions in multilayer wire devices, revealing how their motion and the skyrmion Hall effect are influenced by size, disorder, and device geometry, with implications for high-speed skyrmion-based technologies.

Contribution

It provides a comprehensive experimental and simulation analysis of skyrmion motion and the skyrmion Hall effect in dense arrays, highlighting the effects of edges, size, and pinning.

Findings

Skyrmions reach speeds of 24 m/s in the plastic flow regime.

The skyrmion Hall angle saturates at approximately 22 degrees.

SkHE is weakly dependent on skyrmion size and strongly affected by wire edges.

Abstract

Magnetic skyrmions are nanoscale spin textures touted as next-generation computing elements. When subjected to lateral currents, skyrmions move at considerable speeds. Their topological charge results in an additional transverse deflection known as the skyrmion Hall effect (SkHE). While promising, their dynamic phenomenology with current, skyrmion size, geometric effects and disorder remain to be established. Here we report on the ensemble dynamics of individual skyrmions forming dense arrays in Pt/Co/MgO wires by examining over 20,000 instances of motion across currents and fields. The skyrmion speed reaches 24 m/s in the plastic flow regime and is surprisingly robust to positional and size variations. Meanwhile, the SkHE saturates at $\sim 22^\circ$, is substantially reshaped by the wire edge, and crucially increases weakly with skyrmion size. Particle model simulations suggest that the SkHE size dependence - contrary to analytical predictions - arises from the interplay of intrinsic and pinning-driven effects. These results establish a robust framework to harness SkHE and achieve high-throughput skyrmion motion in wire devices.