La substitution induced linear temperature dependence of electrical resistivity and Kondo behavior in the alloys, Ce_2−xLa_xCoSi₃

Abstract

Results of electrical resistivity (ρ), heat-capacity (C) and magnetic susceptibility (χ) measurements (above 1.5 K) for the alloys of the type, Ce_2−xLa_xCoSi₃, are reported. We find that the S-shaped temperature dependence of ρ for the mixed-valent x=0.0 alloy is not a single-ion property; the most interesting observation is that, for an intermediate concentration, (x=0.25), a linear temperature dependence of ρ below 30 K is found, an observation of relevance to the current trends in the topic of non-Fermi-liquid behavior. Other observations are: (i) Ce exhibits single-ionic heavy-fermion behavior with moderately enhanced electronic contribution to C; and (ii) the strength of the Kondo interaction, as measured by the Curie-Weiss parameter gets reduced for larger substitutions (x > 0.5) of La for Ce.