Berlin 2008 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 14: Magnetic Half Metals and Oxides
MA 14.11: Vortrag
Dienstag, 26. Februar 2008, 13:00–13:15, EB 202
Exotic, anionogenic magnetism in the alkali sesquioxide Rb4O6. — •J. Winterlik1, G. H. Fecher1, C. Felser1, C. Mühle2, M. Jansen2, L. M. Sandratskii3, and J. Kübler4 — 1Institut für Anorganische und Analytische Chemie, Johannes Gutenberg - Universität, 55099 Mainz — 2Max - Planck - Institut für Festkörperforschung, 70569 Stuttgart — 3Max - Planck - Institut für Mikrostrukturphysik, 06120 Halle — 4Institut fü Festkörperphysik, Technische Universität, 64289 Darmstadt
The chemical formula Rb4O6 implies a simple alkali oxide. Taking into account its black color and its mixed valency, things get much more complicated in the case of this so-called rubidium sesquioxide. Up to the present, an accurate description of its electronic structure has not yet been provided. The investigation of temperature dependent magnetic properties indicated p-electron based magnetic frustration. Here, we present experimental results that confirm this proposed magnetic frustration. In addition, we provide a theoretical model for the exceptional crystal of Rb4O6. The introduction of electron-electron correlations on the oxygen p-electrons together with the consideration of the broken crystal symmetry that is caused by the mixed valency lead to results that are consistent with the magnetic experiments. According to these calculations, Rb4O6 exhibits a highly degenerate ground state with a large number of frustrated non-collinear magnetic configurations.