Regensburg 2010 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 14: Spin Dynamics / Spin Torque I
MA 14.5: Vortrag
Mittwoch, 24. März 2010, 10:45–11:00, H10
Ultrafast and Element-Selective Demagnetization Dynamics probed at the M Absorption Edges employing a tabletop High-Harmonic Soft X-ray Source — •Patrik Grychtol1, Chan La-O-Vorakiat4, Roman Adam1, Stefan Mathias2,4, Mark Siemens4, Justin Shaw3, Hans Nembach3, Thomas Silva3, Martin Aeschlimann2, Claus M. Schneider1, Henry Kapteyn4, and Margaret Murnane4 — 1Insitut für Festkörperforschung, IFF-9, Forschungszentrum Jülich, Jülich — 2Technische Universität Kaiserslautern und Forschungszentrum OPTIMAS, Kaiserslautern — 3Electromagnetics Division, National Institute of Standards and Technology, Boulder, Colorado — 4Department of Physics and JILA, University of Colorado, Boulder, Colorado
Employing tabletop soft X-ray sources based on ultrafast laser amplifier for probing magnetic materials promises to combine element-selectivity with a spatial and temporal resolution on the nanometer and femtosecond scales for studying magnetism at fundamental limits. In our T-MOKE experiment where coherent X-ray pulses were reflected off a magnetized Ni80Fe20 grating, large changes in the reflected intensity of up to 6% at the M absorption edges of Fe and Ni were observed upon magnetization reversal. We demonstrate that femtosecond soft X-ray pulses from high harmonic generation can probe the Ni80Fe20 demagnetization in the femtosecond range element-selectively. Ultrafast demagnetization induced by a femtosecond laser pump pulse can be observed at both edges pointing towards a tight exchange coupling of the respective magnetic moments.