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MA: Fachverband Magnetismus
MA 35: Magnetic Heusler Compounds I
MA 35.9: Vortrag
Mittwoch, 28. März 2012, 17:30–17:45, H 0112
Symmetry of valence states of Heusler compounds explored by linear dichroism in hard X-ray photoelectron spectroscopy — •S. Ouardi1, G. H. Fecher1,2, C. Shekhar2, B. Balke1, A. Gloskovskii1, C. Felser1,2, E. Ikenaga3, S. Ueda4, and K. Kobayashi4 — 1Institute of Inorganic Chemistry and Analytical Chemistry, Johannes Gutenberg - University, Mainz — 2Max Planck Institute for Chemical Physics of Solids, Dresden, Germany. — 3Japan Synchrotron Radiation Research Institute, SPring-8, Hyogo, Japan — 4National Institute for Materials Science, SPring-8, Hyogo, Japan
In the present work, a combination of the the linear dichroism in the angular distribution (LDAD) with the bulk-sensitive hard-x-ray photoelectron spectroscopy (HAXPES) technique was used to investigate the symmetry of the valence states of magnetic, semiconducting and gapless Heusler compounds with C1b structure. High-resolution photoelectron spectroscopy was performed with an excitation energy of hν=7.938 keV. The linear polarization of the photons was changed using an in-vacuum diamond phase retarder. The valence band spectra exhibit the typical structure expected from first-principles calculations of the electronic structure of these compounds. Noticeable linear dichroism is found in the valence band of the materials and this allows for a symmetry analysis of the contributing states. The differences in the spectra are found to be caused by symmetry-dependent angular asymmetry parameters, and these occur even in polycrystalline samples without preferential crystallographic orientation.