Preparation of Bi-Pb-Sr-Ca-Cu-O high-Tc superconductor form coprecipitated oxalate

Partial substitution of Pb for Bi in the Bi-Sr-Ca-Cu-O system increases the volume fraction of the high-Tc phase when both the starting materials (coprecipitated oxalate) and the heating process are appropriate. A sharp powder X-ray diffraction pattern of the high-Tc phase was obtained from particles 10-20 μm wide and 0.5μm thick typically. The electrical resistance dropped to zero at 107k within the experimental limit of 10-6Ω. A large diamagnetic response in the ac susceptibility due to the Meissner effect was seen below 120K. The fraction of the high-Tc phase over the low-Tc phase was roughly 9/1 in volume.