Pure and lead doped BiCaSrCuO (2223) compounds have been prepared by solid state reaction at 850°C. In undoped sample the Tc (zero) has been observed at 79K where as in Bi1.75Pb0.25Ca2Sr2Cu3 Oy Tc was obtained at 107K. Increasing the reaction time and rapidly quenching the samples by immersing them in liquid nitrogen, resulted in decrease of Tc. In rapidly quenched samples stepped resistive transitions have been observed. Aging at room temperature over long periods (~Two years) also showed a decrease in Tc and growth of low Tc (2122) phase. Heat treatment and oxygen annealing recovered the high Tc (2223) phase. The growth of low Tc (2122) and high Tc (2223) phase and their inter relationship have been explained.
ASJC Scopus subject areas
- Materials Chemistry