Dresden 2009 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 4: Surface Magnetism I
MA 4.3: Vortrag
Montag, 23. März 2009, 11:30–11:45, HSZ 403
SPEELS Studies of Oxygen Passivated Fe/W(100) Thin Films — •Yu Zhang1, Jacek Prokop1, Ioan Tudosa1, Wen-Xin Tang1, Thiago R. F. Peixoto1,2, Khalil Zakeri1, and Jürgen Kirschner1 — 1Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle — 2Instituto de Física, Universidade de São Paulo, 05508-900, São Paulo, Brazil
We measured the vibrational spectra of oxygen passivated Fe(100) surface by means of spin-polarized electron energy loss spectroscopy (SPEELS). A 30 ML thick Fe film, epitaxially grown on W(100) was exposed to 5 L O2 at room temperature and annealed at 500 K, under ultrahigh vacuum conditions. The surface exhibits a p(1×1)O-Fe(100) reconstruction in the LEED pattern, with the O atoms occupying four-fold hollow sites. SPEELS measurements were performed at different primary energies and a resolution of about 6 meV. These spectra show many peaks in comparison to the spectra obtained for the clean Fe surface. From the analysis of the energy gain and loss features in the asymmetry, one can distinguish between excitations caused by spin-flip and non-flip scattering processes. The O-Fe(100) vibration peaks, which are dominated by the spin independent dipolar scattering [1], surprisingly reveal asymmetries up to 60%. We show results of specular and off-specular geometries and discuss the nature of the observed excitations.
[1] J.-P. Lu, M. R. Albert and S. L. Bernasek, Surf. Sci. 215, 348 (1989).