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

Abstract

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