Single-crystal YBa2Cu3O7 particle formation by aerosol decomposition
Abstract
Single-crystal YBa2Cu3O7 particles have been formed in a carbon-free gaseous flow system by thermally decomposing droplets containing the nitrate salts of Y, Ba, and Cu in water followed by calcining and annealing in the gas phase. The electron diffraction pattern for particles ranging in size from 0.1 to 1.5 μm corresponded to single crystals of orthorhombic YBa2Cu3O7 while the powder x-ray diffraction pattern confirmed the presence of single-phase material. Energy dispersive spectroscopy showed a similar composition for all particles examined. Iodometric titration showed that the particles were fully oxygenated. Two types of single-crystal particles were observed, equiaxed and elongated. Formation of solid single-crystal particles is favored by operation near the melting point of the material and by long reactor-residence times.