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arXiv · 2003.05159

Excitation and relaxation dynamics of spin-waves triggered by ultrafast photo-induced demagnetization in a ferrimagnetic insulator

Yusuke Hashimoto·Koji Sato·Tom H. Johansen·Eiji Saitoh
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Abstract

Excitation and propagation dynamics of spin waves in an iron-based garnet film under out-of-plane magnetic field were investigated by time-resolved magneto-optical imaging. The experimental results and the following data analysis by phase-resolved spin-wave tomography reveal the excitation of spin waves triggered by photo-induced demagnetization (PID) along the sample depth direction. Moreover, the fast relaxation of PID accompanied by the spin transfer due to spin-wave emission was observed. Possible scenarios of PID in the garnet film are discussed. Finally, we develop a model for the spin-wave excitation triggered by PID and explain the magnetic-field dependence in the amplitude of the observed spin waves.

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Yusuke Hashimoto, Koji Sato, Tom H. Johansen, Eiji Saitoh. 2020-03-11. Excitation and relaxation dynamics of spin-waves triggered by ultrafast photo-induced demagnetization in a ferrimagnetic insulator. https://arxiv.org/abs/2003.05159

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