Current-Driven Dynamics of Skyrmions Stabilized in MnSi Nanowires Revealed by Topological Hall Effect

TL;DR

This study uses the topological Hall effect to investigate the stability and current-driven dynamics of skyrmions in MnSi nanowires, revealing extended stability regions and demonstrating skyrmion motion at high current densities.

Contribution

It is the first to analyze skyrmion dynamics in MnSi nanowires using THE, showing extended phase stability and current-driven motion in 1D systems.

Findings

Skyrmion phase stabilized in MnSi nanowires from 15 to 30 K.

High current densities induce skyrmion motion, evidenced by THE decrease.

Nanowires enable exploration of skyrmion physics in 1D systems.

Abstract

Skyrmions, novel topologically stable spin vortices, hold promise for next-generation magnetic storage due to their nanoscale domains to enable high information storage density and their low threshold for current-driven motion to enable ultralow energy consumption. One-dimensional (1D) nanowires are ideal hosts for skyrmions since they not only serve as a natural platform for magnetic racetrack memory devices but also can potentially stabilize skyrmions. Here we use the topological Hall effect (THE) to study the phase stability and current-driven dynamics of the skyrmions in MnSi nanowires. The THE was observed in an extended magnetic field-temperature window (15 to 30 K), suggesting stabilization of skyrmion phase in nanowires compared with the bulk (27 to 29.5 K). Furthermore, for the first time, we study skyrmion dynamics in this extended skyrmion phase region and found that under the high current-density of $10^{8}-10^{9} Am^{-2}$ enabled by nanowire geometry, the THE decreases with increasing current densities, which demonstrates the current-driven motion of skyrmions generating the emergent electric field. These results open up the exploration of nanowires as an attractive platform for investigating skyrmion physics in 1D systems and exploiting skyrmions in magnetic storage concepts.