Current-driven dynamics of skyrmions stabilized in MnSi nanowires revealed by topological Hall effect

Abstract

Skyrmions hold promise for next-generation magnetic storage as their nanoscale dimensions may enable high information storage density and their low threshold for current-driven motion may enable ultra-low energy consumption. Skyrmion-hosting nanowires not only serve as a natural platform for magnetic racetrack memory devices but also stabilize skyrmions. Here we use the topological Hall effect (THE) to study phase stability and current-driven dynamics of skyrmions in MnSi nanowires. THE is observed in an extended magnetic field-temperature window (15-30a €‰K), suggesting stabilization of skyrmions in nanowires compared with the bulk. Furthermore, we show in nanowires that under the high current density of 10 8 -10 9 a €‰Aa €‰m a '2, the THE decreases with increasing current densities, which demonstrates the current-driven motion of skyrmions generating the emergent electric field in the extended skyrmion phase region. These results open up the exploration of skyrmions in nanowires for fundamental physics and magnetic storage technologies.