Restoration of the microstructure of Ba2YCu3O7 − δ at T > 900°C after low-temperature decomposition

Transmission electron microscopy and optical microscopy have been used to study the structure of the nonstoichiometric YBa2Cu3O7 − δ compound subjected to low-temperature annealing (200–300°C) and subsequent restoration annealing at 930–950°C. It was shown that the retention of part of structural defects, which were formed during decomposition and interaction with water vapor, after restoration annealing determines structural state of the compound that is typical of materials exhibiting improved electrophysical characteristics.