Regensburg 2004 – wissenschaftliches Programm

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O: Oberflächenphysik

O 12: Magnetismus in reduzierten Dimensionen

O 12.5: Vortrag

Montag, 8. März 2004, 16:45–17:00, H45

Spin-resolved inverse photoemission with improved energy resolution — •Michael Budke, Volker Renken, Helmut Liebl, Georgi Rangelov, and Markus Donath — Physikalisches Institut, Universität Münster, Wilhelm-Klemm-Str. 10, 48149 Münster

Spin-resolved inverse photoemission (IPE) is a powerful tool that measures the spin-dependend electronic structure above the Fermi level of magnetic surfaces and thin films. We have developed a source for spin-polarized electrons with variable energy resolution from 150 meV to 400 meV (FWHM) at currents between 0.5 µA and 5 µA on the sample. The photon detector consists of a conventional Geiger tube filled with either acetone or iodine [1,2]. MgF₂ is used as entrance window, followed by a SrF₂- or CaF₂-window. The transmission cutoff was shifted by varying the temperature of the windows. With this arrangement the energy resolution of the counters is continuously variable between 150 meV and 400 meV (FWHM). Depending on the experimental requirements the total energy resolution of our IPE system can therefore be varied between 500 meV and nearly 200 meV. The latter value is an improvement of the energy resolution by a factor of two compared to previous spin-resolved IPE systems [3]. [1] Dose V., Appl. Phys. 14, 117 (1977) [2] Funnemann D., Merz H., J. Phys. E: Sci. Instrum. 19, 554 (1986) [3] Dose V., Fauster T., Schneider R., Appl. Phys. A 40, 203 (1986)