Time-resolved observation of magnon splitting into vortex gyration and Floquet spin waves
Phys. Rev. Applied 26, 014037 – Published 13 July, 2026
DOI: https://doi.org/10.1103/kzlb-j3mw
Abstract
Forced excitations at frequencies in the range of the first-order azimuthal spin waves of a magnetic disk in the vortex state are known to scatter into the vortex gyration mode, thereby allowing the growth of Floquet spin waves forming a frequency comb. We study the temporal emergence of this dynamical state using time-resolved microwave electrical measurements. The most intense Floquet mode emerges synchronously with the gyration mode after a common incubation delay, which diverges at the scattering threshold. This delay is minimal when the drive is resonant with one of the first-order azimuthal spin waves. It can be as short as 3 ns for the maximum investigated power. We conclude that the first-to-occur scattering mechanism is the three-wave splitting of a regular azimuthal eigenmode into a coherent pair formed by a gyration magnon and a Floquet spin wave.
