Regensburg 2013 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 50: Poster II

MA 50.49: Poster

Freitag, 15. März 2013, 10:30–13:30, Poster D

Ultrafast Demagnetization in a Kondo-Lattice System — •Alexander Baral and Hans-Christian Schneider — University of Kaiserslautern

We present theoretical results on the magnetization dynamics after ultrashort pulse excitation in a Kondo-lattice model, i.e., a system of 2D carriers coupled by an exchange interaction to a virtual lattice of localized spins. For the itinierant carriers, we include a spin-orbit coupling of the Rashba type as well as carrier-carrier and carrier-phonon scattering. In the framework of this model and starting from a mean-field description and using a dynamical exchange splitting, we investigate the magnetization dynamics after ultrashort-pulse excitation. Such an excitation leads to a demagnetization dynamics reminiscent of that found in 3d- and 4f-ferromagnetic metals.[1] We compute time- and momentum-dependent carrier distribution functions from carrier-carrier and carrier-phonon Boltzmann scattering integrals. In addtion, in our model, the exchange splitting is time-dependent, so that also the spin-mixing changes with time. It is shown that the dynamical exchange splitting and also the dynamical change of the spin mixing hava an important qualitative and quantitative influence on the demagnetization and remagnetization dynamics. [1] Koopmans, B. et al., Nature Mater. 9, 259*265 (2010).