Berlin 2005 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 16: Posters Correlated Electrons, Measuring Devices, Cryotechnique
TT 16.17: Poster
Samstag, 5. März 2005, 11:00–16:30, Poster TU C
Crossover from Single-Ion to Coherent Non-Fermi Liquid Behavior in Ce1−xLaxNi9Ge4 — •E.-W. Scheidt1, U. Killer1, H. Michor2, S. Kehrein3, and W. Scherer1 — 1CPM, Institut für Physik, Universität Augsburg, 86135 Augsburg, Germany — 2Institut für Festkörperphysik, TU Wien, 1040 Wien, Austria — 3TP III – EKM, Institut für Physik, Universität Augsburg, 86135 Augsburg, Germany
We report specific heat , susceptibility and resistivity studies on the compound Ce1−xLaxNi9Ge4 for various concentrations ranging from the stoichiometric system with x=0 to the dilute limit x=0.95 [1]. Our data reveal single-ion scaling with the Ce-concentration and the largest ever recorded value of the electronic specific heat Δ c/T ≈ 5.5 J K−2mol−1 at T=0.08 K for the stoichiometric compound at x=0 without any trace of magnetic order. While in the doped samples Δ c/T and ρ increase logarithmically in the range between 3 K and 50 mK and between 20 K and 5 K, respectively, their magnetic susceptibility behaves Fermi liquid like below 1 K. Δ c/T in CeNi9Ge4 flattens out below 200 mK and displays a pronounced maximum in the resistivity curve at 4K indicating a coherent heavy fermion groundstate [2]. These properties render the compound Ce1−xLaxNi9Ge4 a unique system on the borderline between Fermi liquid and non-Fermi liquid physics. [1] U. Killer, E.-W. Scheidt, G. Eickerling, H. Michor, J. Sereni, Th. Pruschke, S. Kehrein, Phys. Rev. Let. (cond-mat/0402498), in print. [2] E.-W. Scheidt, U. Killer, H. Michor, E. Bauer, C.Dusec, S. Kehrein and W. Scherer, Physika B, in print.