Dresden 2011 – scientific programme
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MA: Fachverband Magnetismus
MA 38: Magnetization Dynamics IV
MA 38.4: Talk
Wednesday, March 16, 2011, 15:30–15:45, HSZ 403
Pump-Probe SAXS experiments on ultrafast demagnetization of magnetic multilayers — B. Pfau1, •S. Schaffert1, J. Mohanty1, J. Geilhufe1, F. Büttner1,2, S. Flewett1, L. Müller3, C. Gutt3, A. Al-Shemmary3, S. Düsterer3, H. Redlin3, G. Grübel3, B. Vodungbo4, J. Lüning5, D. Stickler6, R. Frömter6, H.P. Oepen6, W.F. Schlotter7, and S. Eisebitt1 — 1IOAP, Technische Universität Berlin, Germany — 2Paul Scherrer Institut, Villigen, Switzerland — 3HASYLAB at DESY, Hamburg, Germany — 4ENSTA ParisTech - Ecole polytechnique, Palaiseau, France — 5Université Pierre et Marie Curie, Paris, France — 6Universität Hamburg, Germany — 7LCLS at SLAC, Menlo Park, USA
We have investigated the ultrafast optical demagnetization of domain patterns in magnetic multilayers with perpendicular magnetic anisotropy in an infrared-pump x-ray-probe experiment. As a probe we used small angle x-ray scattering which, via x-ray magnetic circular dichroism at the Co M-edge, allows us to simultaneously obtain information on the magnitude of the local magnetization and the characteristic length scale of the magnetic domains. The free-electron laser source FLASH at Hamburg was tuned to deliver λ=20.9nm x-ray pulses of approx. 25 fs duration which were synchronized to an infrared fs laser for pump-probe experiments with sub-ps time resolution. In addition to ultrafast demagnetization, we observe sub-ps structural changes of the magnetic domain configuration. Models to explain this ultrafast structural change will be discussed.