Visualizing the strongly reshaped skyrmion Hall effect in multilayer wire devices.

Area of Science:

• Condensed matter physics
• Materials science
• Nanotechnology

Background:

• Magnetic skyrmions are nanoscale spin textures with potential for next-generation computing.
• Their motion under current is key, but dynamics like the skyrmion Hall effect (SkHE) need further study.
• Understanding SkHE dependence on current, size, geometry, and disorder is crucial for device applications.

Purpose of the Study:

• To investigate the ensemble dynamics of individual magnetic skyrmions in dense arrays within Pt/Co/MgO wires.
• To establish the dynamic phenomenology of skyrmion motion, focusing on speed and the skyrmion Hall effect (SkHE).
• To determine the influence of current, skyrmion size, and geometric effects on skyrmion dynamics.

Main Methods:

• Ensemble dynamics of individual skyrmions were examined in dense arrays within Pt/Co/MgO wires.
• Over 20,000 instances of skyrmion motion were analyzed across varying currents and fields.
• Particle model simulations were employed to understand the underlying physics of SkHE size dependence.

Main Results:

• Skyrmion speeds reached up to 24 m/s in the plastic flow regime, showing robustness to positional and size variations.
• The skyrmion Hall effect (SkHE) saturated at approximately 22°, was significantly influenced by wire edges, and showed a weak increase with skyrmion size.
• Simulations indicated that SkHE size dependence results from the interplay of intrinsic and pinning-driven effects, contrary to analytical predictions.

Conclusions:

• Skyrmion motion exhibits robust dynamics and a predictable SkHE saturation under specific conditions.
• The study establishes a framework for harnessing the skyrmion Hall effect for high-throughput skyrmion motion in wire devices.
• Findings offer critical insights for the development of skyrmion-based computing technologies.