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Macrospin Models of Spin Transfer Dynamics

Jiang Xiao·A. Zangwill·M. D. Stiles
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Abstract

The current-induced magnetization dynamics of a spin valve are studied using a macrospin (single domain) approximation and numerical solutions of a generalized Landau-Lifshitz-Gilbert equation. For the purpose of quantitative comparison with experiment [Kiselev {\it et al.} Nature {\bf 425}, 380 (2003)], we calculate the resistance and microwave power as a function of current and external field including the effects of anisotropies, damping, spin-transfer torque, thermal fluctuations, spin-pumping, and incomplete absorption of transverse spin current. While many features of experiment appear in the simulations, there are two significant discrepancies: the current dependence of the precession frequency and the presence/absence of a microwave quiet magnetic phase with a distinct magnetoresistance signature. Comparison is made with micromagnetic simulations designed to model the same experiment.

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Jiang Xiao, A. Zangwill, M. D. Stiles. 2005-04-06. Macrospin Models of Spin Transfer Dynamics. https://doi.org/10.1103/physrevb.72.014446

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