Discretized Topological Hall Effect Emerging from Skyrmions in Constricted Geometry

TL;DR

This study demonstrates the quantized topological Hall effect in nano-structured FeGe devices, revealing discrete changes linked to skyrmion dynamics, thus providing insights into skyrmion behavior in confined geometries.

Contribution

It presents the first observation of discretized topological Hall signals associated with individual skyrmion events in nano-structured devices.

Findings

Discrete steps in topological Hall resistivity linked to skyrmion creation and annihilation

Quantized emergent magnetic flux per skyrmion confirmed

Skyrmion dynamics can be monitored via Hall measurements in nano-structures

Abstract

We investigate the skyrmion formation process in nano-structured FeGe Hall-bar devices by measurements of topological Hall effect, which extracts the winding number of a spin texture as an emergent magnetic field. Step-wise profiles of topological Hall resistivity are observed in the course of varying the applied magnetic field, which arise from instantaneous changes in the magnetic nano-structure such as creation, annihilation, and jittering motion of skyrmions. The discrete changes in topological Hall resistivity demonstrate the quantized nature of emergent magnetic flux inherent in each skyrmion, which had been indistinguishable in many-skyrmion systems on a macroscopic scale.