Kondo Effect in Single Crystals of Dilute Y-Ce Alloys

The magnetic susceptibility and electrical resistivity of Ce impurities in single crystals of Y-Ce alloys were measured at temperatures down to 1.5 K in the directions parallel and perpendicular to the c axis of the crystal. The experimental results were interpreted in terms of the Kondo effect and the crystal-field effect. The data show that the crystal field of Y splits the F-2(5/2) ground state of the Ce3+ ion into three doublets, the lowest doublet specified by J(z) = +/- 1/2. The susceptibility, resistivity, and specific heat results at low temperatures show evidence for the existence of a bound state due to the anisotropic Kondo interaction. Analysis of the low-temperature resistivity data yields a Kondo temperature of 40 K, which is independent of the current direction and the Ce concentration. The susceptibility and the resistivity at 0 K are nearly isotropic.