Magnetic, electrical resistivity, heat-capacity and thermopower anomalies in CeCuAs2

TL;DR

This study investigates CeCuAs2, revealing its non-magnetic, Kondo lattice-like behavior with unusual resistivity and heat capacity properties, challenging existing classifications of non-Fermi liquid systems.

Contribution

It provides detailed measurements of magnetic susceptibility, resistivity, heat capacity, and thermopower, highlighting unique properties of CeCuAs2 that differ from typical Ce-based compounds.

Findings

Ce is trivalent with no magnetic order down to 45 mK.

Resistivity shows negative T-coefficient and T^-0.6 dependence at low T.

Heat capacity C/T decreases below 2 K, unlike typical NFL behavior.

Abstract

The results of magnetic susceptibility, electrical resistivity ($\rho$), heat-capacity (C) and thermopower (S) measurements on CeCuAs2, forming in ZrCuSi2-type tetragonal structure, are reported. Our investigations reveal that Ce is trivalent and there is no clear evidence for long range magnetic ordering down to 45 mK. The $\rho$ behavior is notable in the sense that (i) the temperature (T)-coefficient of $\rho$ is negative in the entire range of measurement (45 mK to 300 K) with large values of $\rho$, while S behavior is typical of metallic Kondo lattices, and (ii) $\rho$ is proportional to T-0.6 at low temperatures, without any influence on the exponent by the application of a magnetic field, which does not seem to classify this compound into hither-to-known non-Fermi liquid (NFL) systems. In contrast to the logarithmic increase known for NFL systems, C/T measured down to 0.5 K exhibits a fall below 2 K. The observed properties of this compound are unusual among Ce systems.