Superconductivity in (Gd1.85-xPrxCe0.15) CuO4

We have carried out a systematic study of structural and superconducting characteristics of the system (Gd(1.85-x)Pr(x)Ce(0.15))CuO(4) over the entire composition range. Superconductivity was observed for Gd(0.75)Pr(1.10)Ce(0.15) CuO(4) at 6.5 K. Superconducting transition temperature (T(c)) in this compound was found to increase to 18 K by subjecting it to high Ar pressure annealing. However, attempts to induce superconductivity in the undoped Gd(1.85)Ce(0.15)CuO(4) did not succeed. The results are explained as due to the increased lattice parameters of the doped compound, consequent upon the replacement of Gd(3+)-ion by larger Pr(3+)-ion, and the increase in the charge carrier concentration as a result of high pressure argon annealing.