Electrical and thermal transport properties of the alloy system (Ce_1-xLa_x)Cu₄In

The studies of electrical resistivity, ρ(T), magnetoresistivity, MR, thermoelectric power, S(T) and thermal conductivity, λ(T), of the alloy system (Ce_1-xLa_x)Cu₄In (0 ≤ x ≤ 1) are reported. The room temperature powder X-ray diffraction studies confirm the orthorhombic CeCu_4.38ln_1.62-type crystal structure with space group Pnnm (No. 58) for all investigated compositions across the series. ρ(T) results indicate an evolution from coherent Kondo scattering to incoherent single-ion Kondo scattering, with increased La content x. ρ(T) for each composition at high temperature is described by a -ln(T) behaviour. MR measurements on Ce dilute alloys are interpreted within the single-ion Bethe ansatz description of the Coqblin-Schrieffer model. S(T) results are described by the phenomenological resonance model. λ(T) data increase linearly with temperature from low T and shows a tendency toward saturation above 300 K for dilute Ce alloys. The Lorentz number, L/L₀ and the dimensionless figure of merit, ZT= S²T/λρ increase upon cooling and exhibit maxima at low temperatures.