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 (*r(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 = *gconv + *bT2 fits the data for all alloys with *gconv 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 mueff values in fair agreement with that of a Ce3+-ion. The *r(T) studies illustrate the evolution from Kondo lattice to single-ion Kondo behaviour with increase in La content in the (Ce1-xLax)CusIn alloy series. MR measurements on Cc 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 T*rm (the temperature at which a maximum in *r(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.