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TT: Tiefe Temperaturen

TT 25: Correlated Electrons - Poster Session

TT 25.78: Poster

Mittwoch, 29. März 2006, 14:30–18:30, P1

Quantum Critical Behavior in CeNi_9−xCu_xGe₄. — •E. –W. Scheidt¹, W. Scherer¹, G. Hilscher², and H. Michor² — ¹Chemische Physik und Materialwissenschaften, Universität Augsburg, 86159 Augsburg, Germany — ²Institut für Festkörperphysik, TU Wien, 1040

CeNi₉Ge₄ exhibits unusual non-Fermi liquid (nFl) behavior with the largest ever recorded value of the electronic specific heat Δ c/T ≅ 5.5 JK⁻²mol⁻¹ without showing any trace of magnetic order [1]. Specific heat measurements show that the logarithmic increase of the Sommerfeld coefficient flattens off below 200 mK indicating coherent effects, whereas substitution of Ce by La in CeNi₉Ge₄ supports a single ion scenario as the main reason for the nFL behavior. Here we report on new substitution experiments replacing Ni by Cu. Specific heat and susceptibility results will discussed in the framework of a quantum critical phase transition scenario.

[1] U. Killer, E.-W. Scheidt, G. Eickerling, H. Michor, J. Sereni, Th. Pruschke, S. Kehrein, Phys. Rev. Lett. 92, 27003 (2004)