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Spin pumping and magnetization dynamics in metallic multilayers

Yaroslav Tserkovnyak·Arne Brataas·Gerrit E. W. Bauer
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Abstract

We study the magnetization dynamics in thin ferromagnetic films and small ferromagnetic particles in contact with paramagnetic conductors. A moving magnetization vector causes \textquotedblleft pumping\textquotedblright of spins into adjacent nonmagnetic layers. This spin transfer affects the magnetization dynamics similar to the Landau-Lifshitz-Gilbert phenomenology. The additional Gilbert damping is significant for small ferromagnets, when the nonmagnetic layers efficiently relax the injected spins, but the effect is reduced when a spin accumulation build-up in the normal metal opposes the spin pumping. The damping enhancement is governed by (and, in turn, can be used to measure) the mixing conductance or spin-torque parameter of the ferromagnet--normal-metal interface. Our theoretical findings are confirmed by agreement with recent experiments in a variety of multilayer systems.

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Yaroslav Tserkovnyak, Arne Brataas, Gerrit E. W. Bauer. 2002-12-05. Spin pumping and magnetization dynamics in metallic multilayers. https://doi.org/10.1103/physrevb.66.224403

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