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Mean-field magnetization relaxation in conducting ferromagnets

Yaroslav Tserkovnyak·Gregory A. Fiete·Bertrand I. Halperin
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Abstract

Collective ferromagnetic motion in a conducting medium is damped by the transfer of the magnetic moment and energy to the itinerant carriers. We present a calculation of the corresponding magnetization relaxation as a linear-response problem for the carrier dynamics in the effective exchange field of the ferromagnet. In electron systems with little intrinsic spin-orbit interaction, a uniform magnetization motion can be formally eliminated by going into the rotating frame of reference for the spin dynamics. The ferromagnetic damping in this case grows linearly with the spin-flip rate when the latter is smaller than the exchange field and is inversely proportional to the spin-flip rate in the opposite limit. These two regimes are analogous to the "spin-pumping" and the "breathing Fermi-surface" damping mechanisms, respectively. In diluted ferromagnetic semiconductors, the hole-mediated magnetization can be efficiently relaxed to the itinerant-carrier degrees of freedom due to the strong spin-orbit interaction in the valence bands.

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Yaroslav Tserkovnyak, Gregory A. Fiete, Bertrand I. Halperin. 2004-07-02. Mean-field magnetization relaxation in conducting ferromagnets. https://doi.org/10.1063/1.1762979

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