Electrical resistivity ρ, specific heat C, and magnetic susceptibility χ measurements made on the filled skutterudite CeRu_4As_{12} reveal non-Fermi liquid (NFL) T - dependences at low T, i.e., ρ(T) ∼ T^{1.4} and weak power law or logarithmic divergences in C(T)/T and χ(T). Measurements also show that the T - dependence of the thermoelectric power S(T) deviates from that seen in other Ce systems. The NFL behavior appears to be associated with fluctuations of the Ce valence between 3^+ and 4^+ rather than a typical Kondo lattice scenario that would be appropriate for an integral Ce valence of 3^+.
@article{arxiv.0708.0412,
title = {Non-Fermi liquid behavior in a fluctuating valence system, the filled skutterudite compound CeRu_{4}As_{12}},
author = {R. E. Baumbach and P. C. Ho and T. A. Sayles and M. B. Maple and R. Wawryk and T. Cichorek and A. Pietraszko and Z. Henkie},
journal= {arXiv preprint arXiv:0708.0412},
year = {2009}
}