Understanding process-induced microstructures in RBa2Cu3O7

During the processing of rare earth (R)-barium-copper-oxygen superconductors, a variety of microstructures can be induced. Many processes are designed to avoid forming some structures, but these same processes can result in other structures which degrade the superconducting properties. Because liquid phases can be detrimental, for example, low-temperature calcination is often employed. But the CO₂ gas evolved during calcination leads to the formation of a nanoc-rystalline microstructure which may affect superconducting properties. Textures and defects can be induced by high-temperature and high-pressure deformation. For commercial dreams to become reality, these processing-induced microstructures, and their effects on properties, will have to be understood and controlled.