Regensburg 2007 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 20: Correlated Electrons - Poster Session
TT 20.18: Poster
Mittwoch, 28. März 2007, 14:00–17:45, Poster A
Unusual Single Ion Behavior in CeNi8.6Cu0.4Ge4 near a Quantum Critical Phase Transition — •Ludwig Peyker1, Ernst-Wilhelm Scheidt1, Wolfgang Scherer1, Stephan Kehrein2, and Herwig Michor3 — 1Chemische Physik und Materialwissenschaften, Universität Augsburg, 86159 Augsburg, Germany — 2Fakultät für Physik, LMU München, 80333 München, Germany — 3Institut für Festkörperphysik, TU Wien, 1040 Wien, Austria
We report on specific heat and magnetic susceptibility measurements of the heavy fermion intermetallic system CeNi9−xCuxGe4 for various concentrations ranging from the stoichiometric compound with x=0 to x=1. CeNi9Ge4 reveals the largest ever recorded value of the electronic specific heat Δ C/T ≈ 5.5 J K−2mol−1 at T=80 mK without any magnetic order. This behavior is mainly driven by single ion (Ce) effects due to the competition between Kondo effect and crystal electrical field splitting [1]. Changing the environment of the magnetic ion Ce by replacing Ni with Cu leads to a long range antiferromagnetic order at TN = 180 mK for CeNi8CuGe4. In between CeNi8.6Cu0.4Ge4 reveals a logarithmic temperature dependency in specific heat indicating non Fermi liquid behavior. This behavior will be discussed in 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)