Spin-wave frequency multiplication by magnetic vortex cores

TL;DR

This paper demonstrates that magnetic vortex cores can generate coherent spin-wave harmonics through their gyration, enabling nanoscale, tunable frequency multipliers and advancing frequency comb technology in spin-wave devices.

Contribution

It is the first observation of frequency multiplication via vortex core dynamics in magnetic textures, revealing a universal mechanism for spin-wave frequency comb generation.

Findings

Coherent spin-wave harmonics arise from vortex core gyration.

Vortex motion creates a frequency comb mechanism.

Potential for nanoscale, tunable spin-based frequency multipliers.

Abstract

Frequency multiplication involves generating harmonics from an input frequency, a technique particularly useful for integrating spin-wave devices operating at different frequencies. While topological magnetic textures offer distinct advantages in spin-wave applications, frequency multiplication has not yet been observed in these structures. Here, we study the magnetization dynamics of magnetic vortices formed in micron-sized disks and squares via wide-field magnetic imaging. We found the occurrence of coherent spin-wave harmonics arising from the gyration of vortex cores driven by microwave fields. This phenomenon reveals a universal mechanism where the periodical motion of delta function-like objects such as vortex cores gives rise to a frequency comb. Our results pave the way for creating nanoscale, tunable spin-based frequency multipliers and open new possibilities for frequency comb generation in a variety of systems.