Regensburg 2010 – scientific programme
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MA: Fachverband Magnetismus
MA 33: Poster II
MA 33.77: Poster
Friday, March 26, 2010, 11:00–14:00, Poster B1
Ultrafast Magnetization Dynamics of Fe and Fe Alloys Investigated with Time-Resolved X-ray Spectroscopy — •Andrea Eschenlohr1, Christian Stamm1, Niko Pontius1, Torsten Kachel1, Ilie Radu2, and Hermann A. Dürr1 — 1Helmholtz Zentrum Berlin für Materialien und Energie, Elektronenspeicherring BESSY II, Albert-Einstein-Str. 15, 12489 Berlin — 2Radboud University Nijmegen, Heijendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
The microscopic processes behind laser induced ultrafast demagnetization of ferromagnetic materials are still only partially understood [1, 2]. One particular issue is the femtosecond demagnetization of permalloy, which was shown to proceed much faster than that of pure Ni and Fe in all-optical experiments [2]. At the BESSY II Femtoslicing beamline, we measure x-ray magnetic circular dichroism with a time resolution of 100 fs, which enables us to study laser induced ultrafast demagnetization in an element specific way. Additional x-ray absorption measurements reveal transient, laser induced changes in the electronic structure, visible at the Fe L-edges. We discuss the results in context with previous work on Ni [3].
[1] B. Koopmans et al., Phys. Rev. Lett. 95, 267207 (2005); [2] I. Radu et al., Phys. Rev. Lett. 102, 117201 (2009); [3] C. Stamm et al., Nature Mater. 6, 740 (2007).