Preparation of Bi-Pb-Sr-Ca-Cu-O High-Tc Superconductor from Coprecipitated Oxalate

Abstract

Partial substitution of Pb for Bi in the Bi-Sr-Ca-Cu-O system has been found to increase sharply the volume fraction of the high-Tc phase when both the starting materials, coprecipitated oxalate being used in the present study, and the heating process are appropriate. The sharp powder X-ray diffraction pattern of the high-Tc phase was obtained from well-grown particles, 1020μm 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 estimated to be 9/1 in volume.