Dresden 2011 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

MA: Fachverband Magnetismus

MA 38: Magnetization Dynamics IV

MA 38.8: Talk

Wednesday, March 16, 2011, 16:30–16:45, HSZ 403

Relating Gilbert damping and ultrafast laser-induced demagnetization — •Christian Illg, Jonas Seib, and Manfred Fähnle — Max-Planck-Institut für Metallforschung, Heisenbergstraße 3, 70569 Stuttgart

Two regimes of short-time magnetization dynamics are usually distinguished: First, the dynamics on a time scale of nanoseconds to several picoseconds driven by external magnetic fields or by spin-polarized electrical currents. Second, the dynamics on a time scale of few picoseconds to subpicoseconds when exposing a thin film of Ni, Fe, or Co, e.g., to an optical femtosecond laser pulse. The first regime can be modelled by the Gilbert equation and the second by the Elliott-Yafet relation. There is a great interest to relate these two regimes.

In this talk a relation is established between the conductivity-like contribution to the Gilbert damping α at low temperatures and the demagnetization time τ_M for the ultrafast laser-induced demagnetization at low laser fluences [1]. It is assumed that the same types of spin-dependent electron-scattering processes are relevant for α and τ_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 α/τ_M is in good agreement with the experimental value.

[1] M. Fähnle, J. Seib, and C. Illg, Phys. Rev. B 82, 144405 (2010)