Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 43: Correlated Electrons: Heavy Fermions 2
TT 43.5: Vortrag
Donnerstag, 26. März 2009, 16:45–17:00, HSZ 301
Electronic Correlations and Non-Fermi-Liquid Behaviour in ACu3Ru4O12–Perovskites — •Axel Günther1, Alexander Krimmel1, Alois Loidl1, Wolfgang Krätschmer1, Heiko Dekinger1, Norbert Büttgen1, Ernst-Wilhelm Scheidt2, Denis Sheptyakov3, and Hannu Mutka4 — 1Experimentalphysik 5, Zentrum für elektronische Korrelationen und Magnetismus, Universität Augsburg, 86135 Augsburg, Deutschland — 2CPM, Institut für Physik, Universität Augsburg, 86135 Augsburg, Deutschland — 3Labor für Neutronenstreuung, ETHZ & PSI, 5232 Villigen PSI, Schweiz — 4Institut Laue Langevin, 38042 Grenoble Cedex 9, France
Among the large variety of AC3B4O12–type perovskites, the copper–ruthenates (C=Cu, B=Ru) form a subclass exhibiting strongly correlated electron behaviour. A special feature of these compounds is that the ideal stoichiometry and structure is preserved for a large number of different A–site cations with different valence states. We have systematically studied the electronic properties by specific heat, magnetic susceptibility, transport, NMR/NQR and neutron scattering experiments. The compound A=Ca is a correlated metal showing non–Fermi–liquid behaviour below 2K, as indicated by a logarithmic increase of the specific heat and deviations from a Korringa behaviour of the spin lattice relaxation rate. In the case of A=Pr, an anomaly in the specific heat occurs at 0.5K whose maximum shifts to higher temperatures with increasing magnetic field. Along with data acquired from inelastic neutron scattering we obtain strong indications for a pronounced crystal field splitting.