`Institute for Chemical Research, Kyoto University` `International Joint Usage Research Center`

Research Group of Ono lab, ”Time-domain Measurements of Current-induced Spin Wave Dynamics” (Published in “Physical Review Letters,” 5 January 2012)

Time-domain Measurements of Current-Induced Spin Wave Dynamics Published in “Physical Review Letters“(Online Publication, Jan 5, 2012).	Prof. Ono, T., Assoc Prof. Kobayashi, K., Assist Prof Chiba, D., and Dr. SekiguchiI, K. (from left)
Dr. Sekiguchi, K. (presently, in Keio University), Dr. Yamada, K. (Alumni, in University of Paris-Sud ), Mr. Seo,S-M. (Korea University), Prof. Lee, K-J. (Korea University), Assist Prof. Chiba., D. Assoc Prof. Kobayashi, K. and Prof. Ono, T.
The performance of spintronic devices critically depends on three material parameters, namely, the spin-polarization in the current (P), the intrinsic Gilbert damping (α), and the coefficient of the non-adiabatic spin transfer torque (β). However, there has been no method to determine these crucial material parameters in a self-contained manner. Here we show that P, α, and β can be simultaneously determined by performing a single series of time domain measurements of current-induced spin wave dynamics in a ferromagnetic film.
	Figure1: (a) The spin wave generated by a microwave pulse is subject to a stream of STT introduced by an electric current j, resulting in the variations of both group velocity vg and amplitude A. (b) Electric signals of the spin wave for different gap distances x, demonstrating the propagation of spin wave packets.
Figure2: Experimental data of the current-induced modulations. (a) Spin wave Doppler shift induced by electric current (x=20um). (b) Spin polarizationP measured for several devices with different gap distances. (c) Spin wave attenuation induced by electric current (x=20um). (d) Non-adiabaticity of STT (β) deduced from the attenuation of SW amplitude.
This work was supported in part by Grant-in-Aid for Creative Scientific Research from MEXT and Grant-in-Aid for Scientific Research(S) from JSPS.
Time-domain measurements of current-induced spin wave dynamics by K. Sekiguchi, K. Yamada, S-M. Seo, K-J. Lee, D. Chiba, K. Kobayashi, and T. Ono Physical Review Letters 108, 017203(2012)