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Theory of Magnetodynamics Induced by Spin Torque in Perpendicularly Magnetized Thin Films

M. A. Hoefer·M. J. Ablowitz·B. Ilan·M. R. Pufall·T. J. Silva
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Abstract

A nonlinear model of spin wave excitation using a point contact in a thin ferromagnetic film is introduced. Large-amplitude magnetic solitary waves are computed, which help explain recent spin-torque experiments. Numerical simulations of the fully nonlinear model predict excitation frequencies in excess of 0.2 THz for contact diameters smaller than 6 nm. Simulations also predict a saturation and red shift of the frequency at currents large enough to invert the magnetization under the point contact. The theory is approximated by a cubic complex Ginzburg-Landau type equation. The mode's nonlinear frequency shift is found by use of perturbation techniques, whose results agree with those of direct numerical simulations.

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M. A. Hoefer, M. J. Ablowitz, B. Ilan, M. R. Pufall, T. J. Silva. 2005-09-10. Theory of Magnetodynamics Induced by Spin Torque in Perpendicularly Magnetized Thin Films. https://doi.org/10.1103/physrevlett.95.267206

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