Abstract
We report results on the normal-state (n-state) and the superconducting properties for CeCu2.2Si2 and the quasi-binary alloys Ce1-xMxCu2.2Si2 with M=La (x⩽11 at%) and M=Y(x⩽3 at%). Upon increasing the dopant concentration, the specific heat jump height, ΔC, is depressed much more strongly than Tc. This proves a pair-breaking effect of the La- and Y-induced “Kondo holes” — characterized by temperatures Th, La and Th, Y, that show an anticorrelation to the characteristic temperatures (T∗La, T∗Y) of the underlying Ce1-xMxCu2.2Si2 systems. Compared with La, Y impurities are more efficient in pair breaking and in destroying coherence in the normal state, presumably owing to a less anisotropic scattering potential.
