THE INFLUENCE OF SYNTHESIS CONDITIONS ON BI2SR2CACU2O8+DELTA SUPERCONDUCTORS

The resistivities and the critical temperatures of quenched and furnac e-cooled (FC) samples of Bi2Sr2CaCu2O8+delta are found to be different . The influence of the cooling rate on Bi-2212 is studied with the hel p of x-ray diffraction, scanning electron microscopy and energy disper sive x-ray analysis of pellet and powder samples. There are several fa ctors which influence the resistivity and the critical temperatures in polycrystalline samples. The granular compaction becomes better in th e quenched sample whereas the FC sample has higher porosity. The compo sitional disorder induced by the cooling rate affects the resistivity and the critical temperature to a certain extent. The Cu stoichiometry is closer to two in the FC sample but the critical temperature is fou nd to be smaller than that of the quenched sample.