Local dynamics of topological magnetic defects in the itinerant helimagnet FeGe

TL;DR

This paper investigates the nanoscale dynamics of topological magnetic defects in FeGe, revealing how magnetic edge dislocations depin and move, influencing the material's magnetic behavior and potential device applications.

Contribution

It provides new experimental and simulation insights into the micromagnetic dynamics of topological defects in an itinerant helimagnet, highlighting the role of edge dislocations.

Findings

Magnetic edge dislocations govern nanoscale dynamics in FeGe.

Depinning and motion of dislocations cause mesoscopic perturbations.

Stochastic instabilities reveal complex spatio-temporal defect behavior.

Abstract

Chiral magnetic interactions induce complex spin textures including helical and conical spin waves, as well as particle-like objects such as magnetic skyrmions and merons. These spin textures are the basis for innovative device paradigms and give rise to exotic topological phenomena, thus being of interest for both applied and fundamental sciences. Present key questions address the dynamics of the spin system and emergent topological defects. Here we analyze the micromagnetic dynamics in the helimagnetic phase of FeGe. By combining magnetic force microscopy, single-spin magnetometry, and Landau-Lifschitz-Gilbert simulations we show that the nanoscale dynamics are governed by the depinning and subsequent motion of magnetic edge dislocations. The motion of these topologically stable objects triggers perturbations that can propagate over mesoscopic length scales. The observation of stochastic instabilities in the micromagnetic structure provides new insight to the spatio-temporal dynamics of itinerant helimagnets and topological defects, and discloses novel challenges regarding their technological usage.