Dresden 2011 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 38: Magnetization Dynamics IV
MA 38.8: Vortrag
Mittwoch, 16. März 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 τM 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 τM. 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/τM is in good agreement with the experimental value.
[1] M. Fähnle, J. Seib, and C. Illg, Phys. Rev. B 82, 144405 (2010)