Dresden 2009 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 35: Spin-Dynamics / Spin-Torque IV
MA 35.10: Vortrag
Donnerstag, 26. März 2009, 17:45–18:00, HSZ 04
Magnetization Dynamics of Co-based Heusler Alloys — •Daniel Steil, Tobias Roth, Sabine Alebrand, Mirko Cinchetti, and Martin Aeschlimann — Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
For more than a decade now the microscopic mechanisms responsible for ultrafast magnetization dynamics after strong optical excitation have been investigated. Today the most likely candidates for this process seem to be Elliott-Yafet-type spin-flip processes [1,2]. To give a strong experimental proof for the above assumption, it would be necessary to compare the dynamics of different magnetic materials, while ideally changing only a single parameter of the system. In this context, Heusler alloys serve as a nearly ideal test system for probing the microscopic mechanism driving magnetization dynamics due to their special properties. In particular, many Co-based Heusler alloys have been predicted to be half metallic ferromagnets, exhibiting a minority spin band gap at the Fermi level (EF). Moreover, in the quaternary alloy Co2Mn1−xFexSi (CMFS), the size and position of the band gap with respect to EF can be tuned by changing the Fe content x [3]. This allows drawing direct conclusions about the influence of the band structure on magnetization dynamics. In this talk we will present the results of time-resolved MOKE experiments on CFMS and compare them to the results from Co and other Co-based Heusler alloys.
[1] Koopmans et al, PRL 95, 267207 (2005) [2] Cinchetti et al, PRL 97, 177201 (2006) [3] Balke et al, PRB 74, 104405 (2006)