Preparation Conditions and Morphology of Superconducting Fine Particles in the Bi‐Ca‐Sr‐Cu‐O System Prepared by Spray Pyrolysis

The morphology and crystalline phases of superconducting fine particles with a composition of Bi 2 Ca 1 Sr 2 Cu 2 O x were studied in terms of preparation conditions, using an aerosol flow reactor with varying temperature profiles: constant, increasing, and humped temperature distributions. The temperature profile in the reactor was found to affect greatly the morphology of the superconducting particles produced. The humped distribution with maximum temperatures over 900°C provided solid particles consisting mainly of the 80 K phase, when other preparation conditions were optimized. This finding indicates the possibility of controlling the morphology, as well as the crystalline phases, of superconducting particles by spray pyrolysis.