Influence of the state of the lattice on the pair breaking of manganese in superconducting cadmium

The superconducting transition temperature of crystalline and amorphous cadmium doped with dilute Mn atoms was measured. In the first case the initial depression ofT _c as function of concentration isdT _c /dc=5.4 K/at % and in the second casedT _c /dc=2.65 K/at %. Both systems show non linear behavior at higher concentrations, the one in the crystalline state much more than the one in the amorphous state. While the curve in the amorphous state fits the Abrikosov-Gor'kov theory to the experimental limit of 70 mK, i.e., to within 3% of the critical concentration, the curve in the crystalline state does not, but is interpretable with the Müller-Hartmann-Zittartz theory with a Kondo temperature of10 ^–6 K.Supported by the Deutsche Forschungsgemeinschaft in the Sonderforschungsbereich 125, Fehlordnung in Metallen Aachen, Jülich, Köln.