Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 46: Surface magnetism I (jointly with MA)

O 46.8: Vortrag

Mittwoch, 16. März 2011, 13:00–13:15, CHE 184

A spin polarizing electron mirror for spin-resolved photoelectron microscopy — •Christian Tusche, Martin Ellguth, A. Akin Ünal, Aimo Winkelmann, Alexander Krasyuk, and Jürgen Kirschner — Max-Planck-Institut für Mikrostrukturphysik Halle, D-06120 Halle, Germany

We report on a novel imaging spin-filter for electrons, that allows the parallel detection of the electron spin-polarization over a two-dimensional field of view. The spin-filter is installed in our momentum microscope, consisting of a photoelectron emission microscope (PEEM) optics and a double hemispherical imaging energy analyzer. After the energy analyzer, a reciprocal image is 90 degrees reflected at a tungsten (100) surface. Spin contrast is obtained due to the spin-dependent reflection probability of low energy electrons, while the angle of incidence is conserved in the outgoing elastic (00) diffraction spot [1]. This geometry transfers the full PEEM image, whereas the spatial information is encoded by small deviations of the angel of incidence.

We demonstrate that the magnetic domain structure of cobalt films grown on Cu(100) can be imaged with a resolution better than 500 nm, limited by the natural domain wall width (≈ 400 nm [2]) of the film. The intensity asymmetry, defined by A=[M⁺−M⁻]/[M⁺+M⁻], shows sharp maxima and minima as a function of the scattering energy in the range between 15 eV and 90 eV, whereas a maximum scattering asymmetry of up to A=45% is found.

[1] German Patent DE102005045622B4 (2009)

[2] A. Berger and H. P. Oepen, Phys. Rev. B 45, 12596 (1991)