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R. Demchyna, U. Köhler, Y. Prots, W. Schnelle, M. Baenitz, U. Burkhardt, S. Paschen, U. Schwarz:
"High-pressure synthesis and physical properties of the europium-substituted barium clathrate Ba_8-xEu_xGe₄₃υ₃ (x <= 0.6)";
Zeitschrift für Anorganische und Allgemeine Chemie, 632 (2006), 73 - 78.

High-Pressure Synthesis and Physical Properties of the Europium-Substituted Barium Clathrate Ba_8-xEu_xGe₄₃υ₃ (x 0.6)

R. Demchyna 1, U. Köhler 1, Yu. Prots 1, W. Schnelle 1, M. Baenitz 1, U. Burkhardt 1, S. Paschen 1 2, Ulrich Schwarz, PD Dr. 1 *

1 Dresden, Max-Planck-Institut für Chemische Physik fester Stoffe
2 Current address: Institut für Festkörperphysik, Technische Universität Wien, Wiedner Hauptstraße 8-10 / 138, 1040 Wien
email: Ulrich Schwarz (schwarz@cpfs.mpg.de)

Abstract
The new clathrate Ba_8-xEu_xGe₄₃υ₃ (x = 0.6) was synthesized at a pressure of 1 GPa and temperatures of up to 1220 K by means of a multi-anvil device (Walker module) and a hydraulic 1000 ton press. X-ray powder diffraction data indicate that the crystal structure of Ba8-xEuxGe433 (x = 0.6, space group , a = 21.2588(3) Å) corresponds to that of Ba8Ge433. Measurements of the magnetic susceptibility of Ba8-xEuxGe433 reveal Curie-paramagnetic behaviour and prove that the electronic state of europium corresponds to 4f7, i.e., Eu2+. Electrical resistivity shows a metal-like temperature dependence and (300) 2m cm for x = 0.6. Heat capacity measurements reveal an upturn of cp/T(T) below 7 K that is attributed to magnetic interaction of the europium ions.

High-pressure synthesis; Germanide; Clathrate; Crystal structure; Magnetic susceptibility

http://aleph.ub.tuwien.ac.at/F?base=tuw01&func=find-c&ccl_term=AC06588179

http://dx.doi.org/10.1002/zaac.200500343