Year: 2003
Type: article
Abstract: We study the enhancement of the ferromagnetic relaxation rate in thin films due to the adjacent normal-metal layers. Using linear-response theory, we derive the dissipative torque produced by the $s\ensuremath{-}d$ exchange interaction at the ferromagnet--normal-metal interface. For a slow precession, the enhancement of the Gilbert damping constant is proportional to the square of the $s\ensuremath{-}d$ exchange constant times the zero-frequency limit of the frequency derivative of the local dynamic spin susceptibility of the normal metal at the interface. Electron-electron interactions increase the relaxation rate by the Stoner factor squared. We attribute the large anisotropic enhancements of the relaxation rate observed recently in multilayers containing palladium to this mechanism. For free electrons, the present theory compares favorably with recent spin-pumping results of Tserkovnyak et al. [Phys. Rev. Lett. $88,$ 117601 (2002)].
Authors: E. Šimánek, B. Heinrich
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2029208498