09:45 〜 10:00
▼ [22a-A205-4] Observation of nonlinear spin-wave dynamics by magneto-optical imaging
キーワード：spintronics, spin-wave, imaging
Spin waves have strong nonlinearities due to dipole and exchange interactions, and there are abundant nonlinear processes between spin waves with different wavenumbers. but these nonlinear processes have not been observed in real space due to measurement method limitations.
In this study, second-order Suhl process, a type of nonlinear excitation process, is observed by spin-wave spectroscopy based on time-resolved magneto-optical microscopy which synchronizes the microwave phase and laser pulse timing. In the experiment, microwave was induced in a magnetic garnet Bi1Lu2Fe3.4Ga1.6O12 which is known to have a relatively large Faraday rotation angle. The distribution of each spin-wave mode was obtained by Fourier transforming the measured magnetization dynamics. As a result, it was found that the excitation power dependence of the amplitude of spin waves with finite wavenumber exhibit a threshold. In the presentation, we will discuss the measured threshold behavior and compare it with the numerical calculation.
In this study, second-order Suhl process, a type of nonlinear excitation process, is observed by spin-wave spectroscopy based on time-resolved magneto-optical microscopy which synchronizes the microwave phase and laser pulse timing. In the experiment, microwave was induced in a magnetic garnet Bi1Lu2Fe3.4Ga1.6O12 which is known to have a relatively large Faraday rotation angle. The distribution of each spin-wave mode was obtained by Fourier transforming the measured magnetization dynamics. As a result, it was found that the excitation power dependence of the amplitude of spin waves with finite wavenumber exhibit a threshold. In the presentation, we will discuss the measured threshold behavior and compare it with the numerical calculation.