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MA: Fachverband Magnetismus
MA 14: Magnetization Dynamics II
MA 14.1: Vortrag
Montag, 14. März 2011, 17:00–17:15, HSZ 403
Femtosecond XUV Spectroscopy of Gadolinium and Terbium — •Robert Carley1, Björn Frietsch1, Kristian Döbrich1, Martin Teichmann1, Cornelius Gahl1, Olaf Schwarzkopf2, Philippe Wernet2, Frank Noack1, and Martin Weinelt1,3 — 1Max-Born-Institute, Berlin — 2Helmholtz-Zentrum für Materialien und Energie (BESSY II), Berlin — 3Fachbereich Physik, Freie Universität, Berlin
We present recent results of time-resolved IR-pump-XUV-probe experiments on the ultrafast demagnetization of thin films of Gadolium (0001) and Terbium (0001) on Tungsten (110). The experiments are the first to be done using a newly developed high-order harmonics (HHG) XUV beamline at the MBI. The beamline delivers monochromated XUV pulses of approximately 150 fs duration with a photon energy resolution of up to 150 meV. Following excitation by intense femtosecond infrared (IR) pulses, photoemission with 35 eV photons allows us to directly probe the 4f electrons and their interaction with the valence band, both in the bulk and at the surface, to follow the ultrafast magnetization dynamics in the Lanthanide metals. As signatures of ultrafast demagnetization of the metal by the IR pulse, we see for the first time, rapid strong reduction of the exchange splitting in the valence band. This is followed by a slower demagnetization due to the spin-lattice interaction.