Field-Driven Dynamics of Magnetic Hopfions

Phys Rev Lett. 2021 Dec 17;127(25):257201. doi: 10.1103/PhysRevLett.127.257201.

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 66 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.