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Non-Fermi-liquid behavior in CaCu 3 Ru 4 O 12

2008; American Physical Society; Volume: 78; Issue: 16 Linguagem: Inglês

10.1103/physrevb.78.165126

1550-235X

A. Krimmel, A. Günther, W. Kraetschmer, H. Dekinger, N. Büttgen, A. Loidl, Stefan G. Ebbinghaus, E.-W. Scheidt, Wolfgang Scherer,

Magnetic and transport properties of perovskites and related materials

We present bulk magnetic susceptibility, specific heat, transport, NMR, and NQR results of the perovskite compound ${\text{CaCu}}_{3}{\text{Ru}}_{4}{\text{O}}_{12}$. The data consistently describe a metallic state with a moderately enhanced Sommerfeld coefficient of $\ensuremath{\gamma}=92\text{ }\text{mJ}/\text{mol}\text{ }{\text{K}}^{2}$ and a spin-fluctuation temperature of about 180 K. The heat capacity below 2 K shows a logarithmic increase providing evidence for non-Fermi-liquid (NFL) behavior in ${\text{CaCu}}_{3}{\text{Ru}}_{4}{\text{O}}_{12}$. Further signatures of NFL properties are found in NQR measurements revealing deviations from a Korringa behavior of the spin-lattice relaxation rate. The results are discussed with respect to heavy-fermion and NFL properties in other transition-metal compounds and traditional $f$-electron systems.