Dresden 2011 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 38: Magnetization Dynamics IV

MA 38.10: Vortrag

Mittwoch, 16. März 2011, 17:00–17:15, HSZ 403

Understanding demagnetization dynamics in the Heusler alloy Co₂Mn_1−xFe_xSi — •Daniel Steil¹, Sabine Alebrand¹, Tobias Roth¹, Michael Krauß¹, Takahide Kubota², Mikihiko Oogane², Yasuo Ando², Hans Christian Schneider¹, Martin Aeschlimann¹, and Mirko Cinchetti¹ — ¹Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67653 Kaiserslautern, Germany — ²Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan

We have investigated ultrafast demagnetization in the half-metallic Heusler alloy system Co₂Mn_1−xFe_xSi (CMFS). The two investigated compounds CMS and CFS are predicted to be half metallic [1], with a different lineup of the minority band gap and the Fermi level. In CMS, the Fermi energy is lined up to the top of the valence band, while in CFS to the bottom. Despite such differences, both alloys show remarkably similar magnetization dynamics, as measured by the time-resolved magneto optical Kerr effect. Based on the experimental observations and our recent dynamical model that includes momentum- and spin-dependent carrier scattering [2], we show that magnetization dynamics are dominated by hole spin flips below the Fermi energy, which are not influenced by the band gap [3].

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D. Steil et al., Phys. Rev. Lett. 105, 217202 (2010)