Effect of spin-conserving scattering on Gilbert damping in ferromagnetic semiconductors

TL;DR

This paper theoretically investigates how spin-conserving scattering influences Gilbert damping in ferromagnetic semiconductors, revealing new relaxation channels and effects due to spin-orbit coupling and pure spin currents.

Contribution

It introduces a novel theoretical analysis of spin-conserving scattering effects on Gilbert damping in ferromagnetic semiconductors, highlighting the role of spin-orbit coupling.

Findings

Spin-conserving scattering adds a new spin relaxation channel.

Spin-orbit coupling and pure spin currents interact to affect damping.

Predicted a new contribution to damping from spin current and anisotropic spin-orbit coupling.

Abstract

The Gilbert damping in ferromagnetic semiconductors is theoretically investigated based on the $s$-$d$ model. In contrast to the situation in metals, all the spin-conserving scattering in ferromagnetic semiconductors supplies an additional spin relaxation channel due to the momentum dependent effective magnetic field of the spin-orbit coupling, thereby modifies the Gilbert damping. In the presence of a pure spin current, we predict a new contribution due to the interplay of the anisotropic spin-orbit coupling and a pure spin current.