Field-driven triggering of self-induced Floquet magnons in a magnetic vortex

TL;DR

This study demonstrates experimental control of Floquet magnons in magnetic vortices, showing how vortex core manipulation enables switching between regular and Floquet states via hysteretic behavior.

Contribution

It introduces a method to control Floquet magnons in magnetic vortices through vortex core shifting, revealing hysteretic switching between magnon states.

Findings

Floquet sidebands form frequency combs dependent on vortex core orbit.

Magnetic field shifts enable switching between regular and Floquet magnons.

Nonlinear vortex-magnon model explains multiple stable vortex radii.

Abstract

We report the experimental control of Floquet magnons in a magnetic vortex. Using microwave spectroscopy of vortex state magnetic tunnel junctions (MTJs), we find that self-induced Floquet sidebands form frequency combs whose existence depend on the vortex core orbit. By shifting the vortex core with an applied magnetic field, we switch the system between regular and Floquet magnons at identical drive conditions, demonstrating hysteretic control of the Floquet spectrum. A nonlinear vortex-magnon model shows that this behavior originates from multiple stable vortex gyration radii created by Floquet-mediated feedback. These results establish magnetic state initialization as a means to switch between regular and Floquet magnons.