Muons, micromagnetics, and magnetic skyrmions

by Thomas James Hicken (PSI - Paul Scherrer Institut)

Wednesday 8 May 2024, 14:00 → 15:00 Europe/Zurich

SZ-WBGB/019

Magnetic skyrmions have been the attention of much research in recent years due to their potential applications, including low-energy data storage and neuromorphic computing. Studied with many different techniques, perhaps the most common computational approach applied to skyrmions is micromagnetics, where a continuum approximation of the spatial distribution of the magnetisation is simulated. Conversely, muon-spin spectroscopy (µSR) has been used to understand the behaviour of skyrmion-hosting magnets from a local probe perspective, with results that depend sensitively on the local atomic arrangement near the muon. Intuitively, one might not expect these two techniques to work well together, but in this talk I will discuss two recent studies where we have shown that this is not always the case. In bulk GaV4S8 [1], the changes to the magnetic Hamiltonian as a function of applied pressure were only understandable with a combination of µSR and micromagnetics, whereas for a skyrmion-hosting multilayer stack [2] the depth-dependence of the chiral magnetism can be explained by simulating the µSR spectra using micromagnetic simulations.

[1] T. J. Hicken et al., Magnetism in the Néel-skyrmion host GaV₄S₈ under pressure, Phys. Rev. B 105, 134414 (2022)
[2] T. J. Hicken et al., Depth-dependent magnetic crossover in a room-temperature skyrmion-hosting multilayer, arXiv:2210.06070 (accepted Phys. Rev. B)