CRYSTALLIZATION IN BI2O3-SRO-CAO-CUO SYSTEM, AND THE INFLUENCE OF STOICHIOMETRY, AND OXYGEN-CONTENT ON THE T-C OF BI-2212 CRYSTALS

The homogenous crystallisation zones in the 1/2Bi(2)O(3)-SrO-CaO-CuO s ystem were investigated in air, by melt-solidification. A large number of powder precursors having different cation compositions were melted in yttria stabilised zirconia crucibles, and slowly (5 degrees C/h) c ooled in an axial temperature gradient of similar to 60 degrees C/cm. The size, morphology, and the transition temperature of the grown crys tals led to the determination of the homogenous crystallisation volume of the main superconducting phases. The Bi3+, Sr2+, and Ca2+ cation i nter-substitution provided a way to increase the T-c of this phase up to 95-96K, without the contribution of yttrium For some Bi-2212 crysta ls, the oxygen content was determined, and correlated with the transit ion temperature of this phase.