Regensburg 2013 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 33: Magnetization Dynamics I of 3
MA 33.6: Vortrag
Donnerstag, 14. März 2013, 10:45–11:00, H22
Ultrafast Magnetization Dynamics in Co-Based Heusler Compounds with Tuned Structural Order — •Daniel Steil1, Takahide Kubota2, Mikihiko Oogane2, Yasuo Ando2, Christian G.F. Blum3, Sabine Wurmehl3, Anna Suszka4, Olatz Idigoras4, Andreas Berger4, Martin Aeschlimann1, and Mirko Cinchetti1 — 1Dept. of Physics and Res. Center OPTIMAS, TU Kaiserslautern, Germany — 2Tohoku University, Sendai, Japan — 3IFW Dresden, Germany — 4CIC nanoGUNE, San Sebastian, Spain
Several Heusler compounds are predicted to be half-metallic ferromagnets (FM), making them interesting sources of spin-polarized currents. Time-resolved Kerr magnetometry (TR-MOKE) was suggested as a probe for half-metallicity, as a minority band gap should slow down magnetization dynamics compared to the 3d-FM [1]. However, Heusler compounds typically show magnetization dynamics similar to the 3d-FM [1-3], which has been partly attributed to defect states destroying the half-metallicity [1]. We studied thin films of Co2MnSi (CMS) and Co2FeSi (CFS) with different defect concentrations, as well as bulk single crystals with TR-MOKE to elucidate the influence of defects on magnetization dynamics. Surprisingly, we find no influence of defects on ultrafast dynamics in both systems, but a second demagnetization step in CMS for high defect concentrations. Single crystals of CFS and CMS show similar dynamics as the thin films. We discuss our results considering the DOS of the systems using the model from Ref. [2].
[1] G.M. Müller et al.; NMat 8, 56 (2009) [2] D. Steil et al., PRL 105, 217202 (2010) [3] J.-P. Wüstenberg et al., PSS B 248, 2330 (2011)