CRYSTAL-FIELD EXCITATIONS IN THE HEAVY-FERMION ALLOYS CECU6-XAUX STUDIED BY SPECIFIC-HEAT AND INELASTIC NEUTRON-SCATTERING

The specific heat of CeCu6-xAux with x=0, 0.3, and 0.9, and of the corresponding La homologues has been measured between 1.5 K and 150 K. With increasing x we find progressively better-defined Schottky anomalies arising from the crystal-field splitting, which is attributed to the decrease of the Kondo temperature. Both observations are in line with the results of inelastic neutron-scattering data performed on samples with x=0.5. Overall, the crystal-field splitting does not change very much upon alloying with Au. A detailed analysis shows that for x=0.5 the quasielastic line width is smaller and the inelastic crystal-field transitions are better resolved compared to CeCu6.