Regensburg 2013 – scientific programme

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MA: Fachverband Magnetismus

MA 43: Magnetization Dynamics II of 3

MA 43.2: Talk

Thursday, March 14, 2013, 15:15–15:30, H22

Ultrafast Demagnetization in Ferromagnets: The Influence of Spin flip Scattering and Exchange Splitting Dynamics — •Benedikt Y. Mueller, Hans C. Schneider, and Bärbel Rethfeld — Technical University Kaiserslautern, Germany

The effect of the ultrafast demagnetization process after a femtosecond laser irradiation has been studied intensively for almost two decades [1,2,3] but a complete microscopic theory is still lacking. As a step towards this goal, we propose and analyze a dynamical Elliott-Yafet-type approach that takes into account the effects of spin-orbit interaction as well as the spin-diagonal scattering mechanisms within a microscopic description. Using the density of states of Nickel in our model [4,5] and, additionally, a dynamical splitting between the majority and minority bands, we trace the transient non-equilibrium electron distributions providing an energy-resolved picture of ultrafast magnetization dynamics. We illustrate the importance of the interplay of equilibration of temperatures and chemical potentials between the electrons [6] as well as the changes in the Stoner exchange splitting.

[1] E. Beaurepaire et al., Phys. Rev. Lett. 76, 4250 (1996)

[2] J. Hohlfeld et al., Phys. Rev. Lett. 78, 25 (1997)

[3] B. Koopmans et al., Nature Materials 9, 3 (2010)

[4] B. Rethfeld et al., Phys. Rev. B 65, 214303 (2002)

[5] B. Y. Mueller et al., AIP Conf. Proc. 1461, 609 (2012)

[6] B. Y. Mueller et al., New Journal of Physics 13, 123010 (2011)