Sintering effect on Bi(Pb) Sr Ca Cu O high-Tc superconductors

D.c. electrical resistivity, a. c. magnetic susceptibility and X-ray diffraction techniques have been used to investigate the superconductive and structural properties in the systems Bi1.6Pb0.4Sr2Ca2Cu4.5OY and Bi1.6Pb0.2Sr2Ca2Cu4Oy. It is observed that the preparation method and heating methodology affect the properties of materials. Step sintering is of greater value for magnetic properties of the samples whereas prolonged sintering makes the systems more metallic and a smooth variation in resistivity with temperature is observed. The superconducting phase identified by X-ray diffraction analysis is mainly the high-T-c phase in all the samples. Resistivity and susceptibility measurements also indicate primarily the high-T-c phase. (C) 1998 Chapman & Hall.