Berlin 2008 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 10: Magnetic Materials

MA 10.12: Vortrag

Montag, 25. Februar 2008, 18:00–18:15, H 1028

Variation of the Si content and its influence on the structure of rare-earth silicides — •Tilmann Leisegang¹, Torsten Weißbach¹, Julia Dshemuchadse¹, Christian Graf², Thomas Doert², Enrico Faulhaber³, Matthias Frontzek³, Oliver Stockert⁴, Dimitri Souptel⁵, Günter Behr⁵, Hirale S. Jeevan⁴, Christoph Geibel⁴, and Dirk C. Meyer¹ — ¹Institut für Strukturphysik — ²Institut für Anorganische Chemie — ³Institut für Festkörperphysik — ⁴Max-Planck-Institut f. Chemische Physik fester Stoffe — ⁵Leibniz-Institut für Werkstoffforschung; Dresden, Germany

Rare-earth silicides (RES) exhibit a large variety of interesting low temperature physical properties depending on the Si content. CeSi₂, as an example, exhibits ferromagnetic ordering at low and Kondo behavior at higher Si content. As another example, in CeCu₂Si₂, a heavy Fermion compound, the variation of the Si content can result in dominant antiferromagnetic behavior (Si excess) or superconductivity (Si deficiency). To investigate the influence of the Si content on the crystal structure of several RES and to correlate these results with the physical properties, single crystals with certain compositions were synthesised. The investigations were performed by means of single crystal X-ray diffraction and X-ray absorption spectroscopy at ambient conditions. Modulated structures due to vacancy (CeSi_1.82) and atom (Ho₂PdSi₃) ordering were observed as well as specific additional maxima within electron density maps (CeCu₂Si₂) indicating stacking fault defects.
We thank the DFG within the SFB 463 for financial support.