Spectral shape deformation in inverse spin Hall voltage in Y3Fe5O12|Pt bilayers at high microwave power levels

TL;DR

This study investigates how high microwave power levels cause spectral deformation in microwave absorption and inverse spin Hall voltage signals in YIG|Pt bilayers, highlighting the role of spin-wave excitations.

Contribution

It reveals the spectral deformation mechanisms at high power levels in YIG|Pt bilayers, emphasizing the influence of spin-wave excitations over heating or precession cone opening.

Findings

Resonance field shifts to higher values with increased power.

Spectra become asymmetric at high microwave power levels.

Spin-wave excitations significantly contribute to spectral deformation.

Abstract

We report on the deformation of microwave absorption spectra and of the inverse spin Hall voltage signals in thin film bilayers of yttrium iron garnet (YIG) and platinum at high microwave power levels in a 9.45-GHz TE011 cavity. As the microwave power increases from 0.15 to 200 mW, the resonance field shifts to higher values, and the initially Lorentzian spectra of the microwave absorption intensity as well as the inverse spin Hall voltage signals become asymmetric. The contributions from opening of the magnetization precession cone and heating of YIG cannot well reproduce the data. Control measurements of inverse spin Hall voltages on thin-film YIG|Pt systems with a range of line widths underscore the role of spin-wave excitations in spectral deformation.