The Kondo contribution to the electrical resistivity in UCu5-xNix and the non-Fermi liquid behaviour of UCu4Ni

We report on electrical resistivity measurements performed on polycrystalline samples of UCu5-xNix (x = 0.25, 1). In order to extract the Kondo contribution to the resistivity, the experiments were carried out over a wide temperature range (0.4-800 K). From the analysis of our results, we conclude that the Kondo temperature takes values of TK ∼ 240 K for x = 1 and TK ∼ 245 K for x = 0.25, and that for both Ni concentrations the dominant part of the remarkably high residual resistivity (ρ(0) ∼ 400 μΩ cm) corresponds to the Kondo contribution. These results are discussed in comparison with previous analysis of specific heat and magnetic susceptibility data that produced similar values of TK. We interpret our results in terms of disorder-driven non-Fermi liquid behaviour for UCu4Ni, as indicated by the anomalous temperature dependences of the electrical, thermal and magnetic properties previously observed in this compound