Dresden 2014 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
MA: Fachverband Magnetismus
MA 29: Magnetization Dynamics II
MA 29.2: Vortrag
Mittwoch, 2. April 2014, 15:15–15:30, HSZ 401
Comparison of different theories for femtosecond demagnetization — •Karel Carva1,2, Dominik Legut3, Marco Battiato2, and Peter M. Oppeneer2 — 1Charles University in Prague, Czech Republic — 2Uppsala University, Sweden — 3VSB-Technical University of Ostrava, Czech Republic
Magnetization can be changed by means of very strong laser light on the femtosecond timescale. The Elliott-Yafet electron-phonon spin-flip (EY-SF) scattering has been suggested to be the dominant responsible microscopic mechanism [1]. However, ab initio calculations of EY-SF scattering have found the demagnetization rate to be too low to explain the observed demagnetization, especially for electrons in the thermalized state [2]. A recent publication [3] suggests that a different computational approach must be adopted for EY-SF calculation, which leads to a higher calculated demagnetization rate.
We have calculated the spin-flip Eliashberg function for three ferromagnetic metals Fe, Co and Ni [4]. We consider both thermalized very hot electron distributions, as well as highly non-equilibrium electron distributions that are expected to be present immediately after the fs laser excitation. Based on this we study the difference between the proposed models and the physical relevance of the employed approximations.
[1] B. Koopmans et al., Nature Mater. 9, 259 (2010). [2] K. Carva, M. Battiato, P. M. Oppeneer, Phys. Rev. Lett., 107, 207201 (2011) [3] A.J. Schellekens, B. Koopmans, Phys. Rev. Lett. 110, 217204 (2013) [4] K. Carva et al., Phys. Rev. B 87, 184425 (2013)