Control of magnon frequency combs in magnetic rings

TL;DR

This study investigates how vortex core dynamics influence magnon frequency combs in magnetic rings and disks, demonstrating control over nonlinear spin-wave interactions through external magnetic fields.

Contribution

It reveals how external magnetic fields can restore vortex cores in rings, enabling control of nonlinear magnon dynamics and frequency comb generation in magnetic structures.

Findings

Vortex core dynamics significantly affect magnon spectrum.

External magnetic fields can restore vortex cores in rings.

Controlled nonlinear magnon interactions are achievable.

Abstract

Using Brillouin light scattering microscopy, we study the rich dynamics in magnetic disks and rings governed by non-linear interactions, focusing on the role of vortex core dynamics on the spin-wave eigenmode spectrum. By strongly exciting quantized magnon modes in magnetic vortices, self-induced magnon Floquet states are populated by the intrinsic nonlinear coupling of magnon modes to the vortex core gyration. In magnetic rings, however, this generation is suppressed even when exciting the system over a large power range. To retrieve the rich nonlinear dynamics in rings, we apply external in-plane magnetic fields by which the vortex core is restored. Our findings demonstrate how to take active control of the nonlinear processes in magnetic structures of different topology.