Ground state properties,anisotropy and spin relaxation in diluted Kondo systems Y1-x Ce x Zn

Magnetic susceptibility, magnetization and parastriction measurements are performed on single crystals of Y_1-xCe_xZn solid solutions. The crystal field splitting and the linewidth of magnetic excitations are measured by inelastic neutron scattering; coupling constantsJn(E_F) between 4 electron and conduction band are deduced. Low field susceptibility and parastriction experiments both suggést a 8 ground state. However, the magnetization under high fields and its anisotropy are close to those predicted for a 7 ground state. These contradictions may be attributed to the perturbation of the wave functions of the quartet ground state, due to hybridisation with the conduction band. This occurs since the Kondo temperature is not negligible compared to the crystal field splitting.