Unusual behavior of the Kondo temperature of La1-xYbxCu3Al2 - art. no. 165114

Electrical-resistivity (rho), specific-heat (c), and magnetization (M) meas urements were carried out for the series of compounds La1-xYbxCu3Al2(O less than or equal tox less than or equal to1). The resistivity results show tw o regions with a -1n T behavior, with different slopes that allows an estim ation of the crystal-field (CF) splitting. Starting at x = 1, the susceptib ility is reduced to x = 0.4, and this can be explained by the CF effect. Us ing the specific-heat and magnetic-susceptibility data, we were able to det ermine the Kondo temperature (T-K), the crystal-field splitting, and the De bye temperature (theta (D)) for the whole series. T-K was found to increase with the Yb concentration and with the corresponding unit-cell volume cont raction. This behavior suggests the increase of the product \Jn(E-f)\ when the volume is reduced. This is the same trend found in Ce compounds, which is unusual for Yb compounds.