Regensburg 2007 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 4: Electron Theory of Magnetism
MA 4.1: Vortrag
Montag, 26. März 2007, 10:15–10:30, H23
Magnetic EXAFS on Fe/Ag(100): Experiment and Theory — •J. Kurde1, N. Ponpandian1, J. Luo1, C. Sorg1, K. Baberschke1, and H. Wende1,2 — 1Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin-Dahlem, Germany — 2Angewandte Physik, Fachbereich Physik, Universität Duisburg-Essen, Lotharstr. 1, D-47048 Duisburg, Germany
The L2,3 edges of a bcc iron film (13 ML) on Ag(100) have been investigated with magnetic EXAFS (MEXAFS). The absorption spectra were recorded in a k range up to 12 Å−1. The normal or spin-averaged EXAFS confirmes clearly a bcc structure. The well known differences [1] of the spin-averaged and magnetic spectra are observed. Beyond this significant intensities for distances larger than 6 Å in the Fourier transform of the magnetic signal are seen and analysed. To achieve a more fundamental understanding of the spin-selective scattering phenomena that determine the MEXAFS, we applied two theoretical models: 1) ab initio calculations and 2) the rigid band model [2]. From 1) we can identify each contributing scattering path. Method 2) works surprisingly good, since we can clearly reproduce the observed structures. Hence, one can describe the magnetic scattering by a spin-dependend shift of the scattering potential due to exchange coupling, which can be modeled by the energy-shifted EXAFS spectra. Supported by BMBF (05 KS4 KEB 5).
[1] H. Wende et al., J. Synch. Rad. 6, 696 – 698 (1999)
[2] H. Wende, Rep. Prog. Phys. 67, 2105-2181 (2004)