La substitution induced linear temperature dependence of electrical resistivity and Kondo behavior in the alloys, Ce2-xLaxCoSi3

Results of electrical resistivity (rho), heat-capacity (C) and magnetic sus ceptibility (chi) measurements (above 1.5 K) for the alloys of the type, Ce 2-xLaxCoSi3, are reported. We find that the S-shaped temperature dependence of rho for the mixed-valent x = 0.0 alloy is not a single-ion property; th e most interesting observation is that, for an intermediate concentration, (x = 0.25), a linear temperature dependence of rho below 30 K is found, an observation of relevance to the current trends in the topic of non-Fermi-li quid behavior. Other observations are: (i) Ce exhibits single-ionic heavy-f ermion 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. (C) 1999 Elsevier Science Ltd. All rights reserved.