Berlin 2015 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 20: POSTER Ib
MA 20.2: Poster
Dienstag, 17. März 2015, 09:30–13:00, Poster A
Ab initio investigation of light-induced relativistic spin-flip effects in femtosecond magneto-optics — •Ritwik Mondal1, Marco Berritta1, Karel Carva1,2, and Peter M. Oppeneer1 — 1Uppsala University, Uppsala, Sweden — 2Charles University, Prague, Czech Republic
Excitation of a metallic ferromagnet such as Ni with an intensive fs laser pulse causes an ultrafast demagnetization within ∼300 fs. It was proposed that this could be due to relativistic light-induced processes: direct light-induced spin-flip1 or coherent relativistic electrodynamic processes2 (see also3). We perform an ab initio study of the influence of these relativistic effects on the magneto-optical response of Ni. We compute the influence of relativistic spin-flip transitions and develop response theory for ultra-relativistic terms due to the electromagnetic field. Our ab initio calculations of relativistic spin-flip optical excitations predict that these give only a very small contribution to the laser-induced demagnetization. Support from the EU (grant No. 281043, FemtoSpin) is acknowledged.
1G.P. Zhang et al., Nature Phys. 5, 499
(2009). 2J.-Y. Bigot et al., Nature Phys. 5, 515 (2009).
3 K. Carva et al., Nature Phys. 7, 665 (2011).