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arXiv · 0805.3306

Non-equilibrium thermodynamic study of magnetization dynamics in the presence of spin-transfer torque

Kazuhiko Seki·Hiroshi Imamura
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Abstract

The dynamics of magnetization in the presence of spin-transfer torque was studied. We derived the equation for the motion of magnetization in the presence of a spin current by using the local equilibrium assumption in non-equilibrium thermodynamics. We show that, in the resultant equation, the ratio of the Gilbert damping constant, $α$, and the coefficient, $β$, of the current-induced torque, called non-adiabatic torque, depends on the relaxation time of the fluctuating field $τ_{c}$. The equality $α=β$ holds when $τ_c$ is very short compared to the time scale of magnetization dynamics. We apply our theory to current-induced magnetization reversal in magnetic multilayers and show that the switching time is a decreasing function of $τ_{c}$.

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Kazuhiko Seki, Hiroshi Imamura. 2008-05-21. Non-equilibrium thermodynamic study of magnetization dynamics in the presence of spin-transfer torque. https://doi.org/10.1103/physrevb.78.060402

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