PREPARATION OF AG-DOPED NDBA2CU3O7-DELTA SUPERCONDUCTORS BY A SOL-GELMETHOD

Ag-doped NdBa2Cu3O7-delta superconducting ceramics were prepared by a sol-gel method. Ag was distributed uniformly in the sintered samples. The incongruent melting temperature of the NdBa2Cu3O7-delta samples pr epared by our sol-gel method was lower than that of the samples prepar ed by the conventional powder method. The incongruent melting temperat ure was further decreased by doping with Bg. The authors consider that the incongruent melting is induced by reaction between NdBa2Cu3O7-del ta and Ag. The superconducting transition width Delta T(Delta = T-c(on set) - T-c(end)) was decreased by doping with Ag. The electrical resis tivity of a 10 mass% Ag-doped sample dropped sharply from 93 K (T-c(on set)) and showed zero resistivity at 86 K T-c(end)).