Berlin 2005 – wissenschaftliches Programm

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M: Metallphysik

M 8: Symposium Complex Metallic Alloys, Hauptvortrag Esther Belin-Ferré

M 8.1: Hauptvortrag

Freitag, 4. März 2005, 14:45–15:15, TU H1058

Electronic structure of Frank-Kasper Al-Mg based compounds — •Esther Belin-Ferré — Laboratoire de Chimie Physique Matière et Rayonnement, UMR 7614, 11 rue Pierre et Marie Curie, 75231 Paris cedex 05, France
In the Al-Mg Frank-Kasper system, the stable crystalline β -Al₃Mg₂ compound possesses a large cubic unit cell decorated with a complex packing of tetrahedral and icosahedral clusters. Furthermore, quasiperiodic compounds are found in the Al-Mg as well as Al-Mg-Zn systems. The electronic structure of these complex intermetallic compounds was investigated using X-ray emission and X-ray photoabsorption spectroscopy techniques, which allow us to describe separately the energy distribution of occupied and unoccupied states around Al and (or) Mg elements in the solid. The data are averaged over the various Al and (or) Mg sites. The paper will report and discuss these spectroscopic data with emphasis put on the β -Al₃Mg₂ compound. In this compound, the Al and Mg electronic distributions depart from that in the pure Al and Mg metals. A faint pseudo-gap is found at the Fermi level, indicating that in spite of its complex atomic structure, β -Al₃Mg₂ still retains metallic character.