Dresden 2009 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 33: Postersession Correlated Electrons: Metal Insulator Transition, Spin Systems and Itinerant Magnets

TT 33.25: Poster

Mittwoch, 25. März 2009, 14:00–18:00, P1A

Synthesis and properties of the filled skutterudites CePt₄Ge₁₂ and SmPt₄Ge₁₂ — •Walter Schnelle, Roman Gumeniuk, Andreas Leithe-Jasper, Helge Rosner, Michael Nicklas, Michael Baenitz, Michael Schöneich, Marcus Schmidt, Ulrich Schwarz, and Yuri Grin — MPI für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden, Germany

While the ternary platinum-germanium skutterudites with the trivalent rare-earths La and Pr are superconductors the isostructural compounds with Ce, Nd³⁺ and Eu²⁺ order antiferromagnetically [1]. Recently, isotypic SmPt₄Ge₁₂ was prepared at high pressure and XAS measurements reveal that the valence of samarium is temperature-independent and close to 3+. Magnetization data show typical van-Vleck paramagnetic behaviour at elevated temperatures. The low-temperature specific heat displays a field-independent Schottky-type anomaly and a large linear coefficient γ. CePt4Ge₁₂ shows a typical valence fluctuation behaviour with an average Ce valence close to 3+. Together with electronic band structure calulations and NMR investigations [2] we discuss the low-temperature behaviour of these new compounds.

[1] R. Gumeniuk et al. Phys. Rev. Lett. 100 (2008) 017002.

[2] M. Baenitz et al. this conference.