Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 46: Surface magnetism I (jointly with MA)

O 46.9: Vortrag

Mittwoch, 16. März 2011, 13:15–13:30, CHE 184

(SP)VLEED: Experimental access to the spin-dependent surface barrier — •Kathrin Wulff, Anke B. Schmidt, and Markus Donath — Physikalisches Institut, Westfälische Wilhelms-Universität Münster, 48149 Münster

We present the first spin-polarized very-low-energy electron-diffraction (SPVLEED) measurements on a ferromagnetic system.

The fine structures, which appear in intensity vs. energy I(V) profiles of elastically reflected electrons [1], are sensitive to the shape of the surface-barrier potential. On the vacuum side far from the surface, the potential resembles the well-known Coulomb-like shape, while, on the crystal side, it merges the inner potential. In theoretical calculations the transition region, i.e. the surface barrier, is usually described by a parameterized phenomenological model. Our experiment gives access to exactly this transition region.

On Co/Cu(001) we found a significant spin dependence of the reflected intensities that varies strongly with incidence and azimuth angles. It should be noticed that the spin-dependent reflectivity of very-low-energy electrons from ferromagnetic surfaces has recently been utilized in electron spin polarimeters [2,3].

[1] R.O. Jones, P.J. Jennings, Surf. Sci. Reports 9, 165 (1988) ; [2] A. Kakizaki et al., Rev. Sci. Instrum. 79 (2008) 123117 ; [3] A. Winkelmann et al., Rev. Sci. Instrum. 79 (2008) 083303