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Publication Citation: Macrospin Models of Spin Transfer Dynamics

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Author(s): J Xiao; A Zangwill; Mark D. Stiles;
Title: Macrospin Models of Spin Transfer Dynamics
Published: July 01, 2005
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 to experiment [S. I. Kiselev, J. C. Sankey, I. N. Krivortov, N. C. Emley, R. J. Schoelkopf, R. A. Buhrman, and D. C. Ralph, Nature 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. Although many features of experiment appear in the simulations, there are two significant discrepancies: the current dependence of the precession frequency and the presence and/or absence of a microwave quiet magnetic phase with a distinct magnetoresistance signature. Comparison is made to micromagnetic simulations designed to model the same experiment.
Citation: Physical Review B (Condensed Matter and Materials Physics)
Volume: 72
Issue: 1
Pages: pp. 014446-1 - 014446-13
Keywords: giant magnetoresistance;Landau-Lifshitz-Gilbert;macrospin;magnetization dynamics;micromagnetics;microwave;precession;spin valve;spin-transfer torque
Research Areas: Nanomagnetics