Specific heat, susceptibility, magnetotransport and thermoelectric power of the Kondo alloys (Ce1-xLax)Cu5In

The influence of substituting Ce with La in the Kondo compound CeCu5In has been investigated using x-ray diffraction, specific heat (Cp), electrical resistivity (?(T)), magnetoresistivity?(MR) and thermoelectric power?(TEP) measurements. Cp of CeCu5In and the (Ce1?xLax)Cu5In alloys shows enhanced values at low temperatures. Between?10 and 20?K the equation Cp/T = ?conv+?T2 fits the data for all alloys with ?conv scaling linearly with Ce concentration. Below 10?K a pronounced upturn in Cp values occurs. Susceptibility data above 100?K follow the Curie?Weiss relation and give effective moment ?eff values in fair agreement with that of a Ce3+-ion. The ?(T) studies illustrate the evolution from Kondo lattice to single-ion Kondo behaviour with increase in La content in the (Ce1?xLax)Cu5In alloy series. MR measurements on Ce dilute alloys are interpreted within the single-ion Bethe ansatz description and values of the Kondo temperature TK are calculated. A compressible Kondo lattice model has been used to describe the decrease in TK and in Tm? (the temperature at which a maximum in ?(T) occurs for the coherent dense Kondo alloys) with decrease in Ce concentration for these alloys. The TEP is positive and shows a maximum at approximately 45?K for several investigated (Ce1?xLax)Cu5In alloys.