SYNTHESIS OF NEARLY SINGLE-PHASE (HG, PB)BA2CA2CU3O8+DELTA SUPERCONDUCTORS

An ''encapsulation and single-firing'' technique was successfully utilized for the preparation of nearly single-phase polycrystalline samples of (Hg1-xPbx)Ba2Ca2Cu3O8+delta [(Hg, Pb)-1223] with various Pb contents, 0 less than or equal to x less than or equal to 0.3. All the as-sintered samples with x less than or equal to 0.3 exhibited bulk superconductivity at similar to 133K. After post-annealing in flowing O-2 gas, T-c(mag) of (Hg, Pb)-1223 decreased with increasing x, e. g., T-c(mag) similar to 124K for the sample with x=0.3. Thus, oxygenated (Hg, Pb)-1223 samples were likely to be in the overdoped region.