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

Published

December 31, 2005

Author(s)

Mark Hoefer, Mark J. Ablowitz, Boaz Ilan, Matthew Pufall, Thomas J. Silva

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 preduct a saturation and redshift 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.

Citation

Physical Review Letters

Volume

95

Issue

267206

Pub Type

Journals

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Keywords

Ginzburg-Landau equation, Landau-Lifshitz equation, magnetic thin film, nonlinear differential equation, perturbation solution, point contact, spin-momentum transfer

Citation

Hoefer, M. , Ablowitz, M. , Ilan, B. , Pufall, M. and Silva, T. (2005), Theory of Magnetodynamics Induced by Spin Torque in Perpendicularly Magnetized Thin Films, Physical Review Letters, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=32034 (Accessed October 11, 2025)