Suppression of superconductivity in GdPr-123 system

Fourteen single phase polycrystalline ceramic Gd/sub 1-x/ Pr/sub x/ Ba/sub 2/, Cu/sub 3/ O/sub 7-y/ (Gd Pr-123) samples with different Pr doping concentration, x, have been prepared by the standard sintering technique and characterized by FXRD, SEM, TGA, and DT. The electrical resistivity measurements show that at X/sub cr/ = 0.45 superconductivity disappears. These data show that the T/sub c/(x) curve has two plate aux which appear at a 0-0.05 and x = 0.15-0.25. hence T/sub c/ (x) in this system does not follow the prediction of the Abrijkosov- Gorkov (AG) magnetic pair breaking theory. Based on the qualitative similarities among the physical properties of this system and the oxygen depleted RBa/sub 2/Cu/sub 3/O/sub 7-y/ (R-123) (R:Y or rare earth except Ce, Pr, Tb, Pm) system, such as T/sub c/(x) to T/sub c/(y) rho (T,x) to rho (T,y), we suggest that the increasing band filling and localization of states due to the disorder effects, together with Pr doping, could cause an 'effective' increasing of the oxygen deficiency in this system. This implies that a chain-plain correlation (CPC) effect is responsible for the high-T/sub c/ superconductivity. (author)