Relating Gilbert damping and ultrafast laser-induced demagnetization

Abstract

Based on the breathing Fermi-surface model of Gilbert damping and on the Elliott-Yafet relation for the spin-relaxation time, a relation is established between the conductivitylike contribution to the Gilbert damping $\ensuremath{\alpha}$ at low temperatures and the demagnetization time ${\ensuremath{\tau}}_{\text{M}}$ for ultrafast laser-induced demagnetization at low laser fluences. Thereby it is assumed that, respectively, the same types of spin-dependent electron-scattering processes are relevant for $\ensuremath{\alpha}$ and ${\ensuremath{\tau}}_{\text{M}}$. The relation contains information on the properties of single-electron states which are calculated by the ab initio electron theory. The predicted value for $\ensuremath{\alpha}/{\ensuremath{\tau}}_{\text{M}}$ is in good agreement with the experimental value.