Field-driven dynamics of magnetic Hopfions

TL;DR

This study uses micromagnetic simulations to explore the resonant spin wave modes of magnetic Hopfions, revealing a transition to torons at a specific magnetic field and identifying spectral fingerprints for experimental detection.

Contribution

It provides the first detailed analysis of spin wave modes in magnetic Hopfions and their transition to torons, highlighting unique spectral and localization features.

Findings

Resonant modes up to 15 GHz identified

Sharp transition at 32 mT from Hopfions to torons

Distinct spectral fingerprints differentiate topological states

Abstract

We present micromagnetic simulations on resonant spin wave modes of magnetic Hopfions up to 15 GHz driven by external magnetic fields. A sharp transition is found around 32 mT coinciding with a transition from Hopfions to magnetic torons. The modes exhibit characteristic amplitudes in frequency space accompanied by unique localization patterns in real space, and are found to be robust to damping around topological features, particularly vortex lines in Hopfions and Bloch points in torons. The marked differences in spin wave spectra between Hopfions, torons and target skyrmions can serve as fingerprints in future experimental validation studies of these novel 3d topological spin textures.