Current-induced Spin Wave Dynamics: Detection of Non-adiabatic Spin Transfer Torque in Adiabatic Limit
Spin-polarized current flowing though ferromagnet can exert torques on various local magnetic structures: spin waves, magnetic vortex core, and domain walls. Among these, the interplay between spin waves and spin polarized electron transport figures out the basic nature of spin transfer physics .
In this talk, I would like to report on the current-induced Doppler shift which sheds a new light on the interplay between spin polarized transport and magnetization dynamics . By working in time-domain, the contribution of the non-adiabatic torque to spin dynamics is extracted as a change of spin-wave waveform. Since the spin waves used in this experiment have long wave-lengths, the spin of electron adiabatically obeys to the local magnetic structure. The detection of non-adiabatic contribution in the adiabatic limit suggests a microscopic clue to understand the spin transport in ferromagnetic structures. By improving the resolution of propagating spin wave spectroscopy to determine SW amplitude, it could serve as a standard tool to estimate the above three parameters governing the STT physics.
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