Dresden 2009 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 32: Surface or interface magnetism
O 32.6: Vortrag
Mittwoch, 25. März 2009, 11:45–12:00, SCH A315
Time-Of-Flight and Spin Filtering in Low Energy Electron Microscopy — •Lushchyk P.1, Hahn M.1, Schönhense G.1, Oelsner A.2, Panzer D.2, Krasyuk A.3, and Kirschner J.3 — 1Institut für Physik, Johannes Gutenberg Universität Mainz — 2Surface Concept GmbH, Staudingerweg 7, 55128 Mainz — 3Max-Planck-Institut für Mikrostrukturphysik, Halle
The spin degree of freedom in microscopy is exploited in SEMPA [1] and SP-LEEM [2] using diffraction of polarised electrons from magnetic surfaces for generating high magnetic contrast. We are developing two alternative approaches by implementing an imaging spin-filter into the column of a low-energy microscope. In the first set-up, spin-polarised electron diffraction from a single crystal surface is used for spin filtering. The method makes use of the Bragg condition for the electron rays in combination with spatial separation of the rays analogous to an optical mirror. An alternative method uses spin dependent transmission through an ultra thin ferromagnetic foil at low electron energies. From spectroscopy experiments it is known that the optimum analysing power of such a transparent foil can be very high due to the differences in inelastic mean free path for low-energy electrons in ferromagnets [3].
Funded by DFG (Scho 341/9)
[1] H.P. Oepen, J. Kirschner, Scanning Microsc. 5 (1991) 1 [2] Th. Duden, E. Bauer, Surf. Rev. Lett. 5 (1998) 1213 [3] G. Schönhense, H. C. Siegmann, Ann. Phys. 2 (1993) 465