Macrospin Models of Spin Transfer Dynamics

Published

July 1, 2005

Author(s)

J Xiao, A Zangwill, Mark D. Stiles

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

Pub Type

Journals

Keywords

giant magnetoresistance, Landau-Lifshitz-Gilbert, macrospin, magnetization dynamics, micromagnetics, microwave, precession, spin valve, spin-transfer torque

Citation

Xiao, J. , Zangwill, A. and Stiles, M. (2005), Macrospin Models of Spin Transfer Dynamics, Physical Review B (Condensed Matter and Materials Physics) (Accessed October 17, 2025)