In Situ Observations of the Growth Process of C-Axis-Oriented Bi2Sr2Ca1Cu2Ox Superconducting Phase

Abstract
The growth process of the highly oriented microstructure of Bi2Sr2Ca1Cu2O x (2212) crystalline phase has been studied by a method of in situ high-temperature microscopy. The melting state of calcined powders and growth of 2212 crystals on an Ag foil substrate have been directly observed by an optical microscope. The 2212 calcined powders are resolved into a mixed phase at 890°C, which consists of liquid, Bi-free crystalline and Cu-free crystalline phase. The composition of the liquid phase is closer to Bi2Sr2Cu1O x than to Bi2Sr2Ca1Cu2O x of the starting material. The plate-shaped Bi2Sr2Ca1Cu2O x crystals are grown with the a-b planes parallel to the free surface of molten samples.