DIFFERENCES BETWEEN CA-TH AND CA-PR DOPED 1 2/3 SUPERCONDUCTORS - EVIDENCE FOR DISORDER-DEPRESSED T-C FOR CA-TH DOPING/

Charge-neutral doped 1:2:3 superconductors have been studied in well c haracterized sintered samples of Y- and Nd-based hosts with Ca-Pr and Ca-Th doping. The superconducting T-C, the electrical resistivity, and the relative change of the upper critical field slope dH(c2)(T)/dT we re investigated. The results show that the depression of T-C in Ca-Th doped 1:2:3 systems is correlated with an increase in the resistivity. Conventional disorder theories were found to qualitatively describe t hese data as well as published results for irradiated thin films. Sign ificant differences between Ca-Th and Ca-Pr doping were found both in the much stronger depression of T-C as a function of the increase in r esistivity for Ca-Pr doped samples and in the different doping depende nces of the upper critical field slope.