Dresden 2009 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 6: Postersession Correlated Electrons: (General) Theory, Low-Dimensional Systems, Kondo Physics, Heavy Fermions, Quantum-Critical Phenomena

TT 6.53: Poster

Montag, 23. März 2009, 13:00–16:45, P1A

Ge based filled skutterudites MPt₄Ge₁₂: a ¹⁹⁵Pt NMR study. — •M. Baenitz, R. Sarkar, R. Gumenik, A. Leithe-Jasper, W. Schnelle, H. Rosner, U. Burkhardt, M. Schmidt, U. Schwarz, Yu. Grin, and F. Steglich — Max-Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany.

Filled skutterudites MT₄X₁₂(M: alkaline or rare earth metals, T: Fe, Ru, Os, X: P, As, Sb) show a wide variety of strongly correlated electron physics from heavy fermions to Kondo insulators to unconventional superconductors. The new type of skutterudites, the Ge based system MPt₄Ge₁₂ form with M = Ba, Sr, La, Ce, Pr, Sm, Eu[1,2]. They exhibit metallic behaviour and show, with the exception of the systems with Ce, Sm and Eu, superconductivity at low temperature (T_c<10 K)[1,2]. Here we present a temperature dependent ¹⁹⁵Pt NMR study on the whole series of MPt₄Ge₁₂ compounds with special attention on the magnetic systems with Ce, Sm and Eu. Here shift ¹⁹⁵K(T) and spin lattice relaxation rate are discussed in the context of a dense Kondo system with a mixed valence state of Ce as well as for Sm. Especially the pronounced maximum observed in ¹⁹⁵K(T) provides very strong evidence for a mixed valence behavior for this new class of material.

[1] Phys. Rev. Lett. 100, 017002 (2008).

[2] Phys. Rev. Lett. 99, 217001 (2007).