Studies on the oxygen stoichiometry in superconducting cuprates by thermoanalytical methods

Thermoanalytical methods provide important means for studying oxygen stoichiometries in high T-c superconducting cuprates. The optimum annealing temperature for a desired oxygen content in the superconducting product or in related materials can be established by thermogravimetric measurements. By performing the final annealing in a thermobalance the amount of the incorporated or released oxygen can be conveniently both controlled and determined. Furthermore, the absolute oxygen content in the end product can be analyzed by the thermogravimetric reduction method. Finally, the stability of the oxygen content under various atmospheres can be checked utilizing either thermogravimetric or differential thermal analysis techniques. The potential and applications of thermal analysis within the above themes of cuprate superconductor research are reviewed and discussed using illustrative examples from the authors' own experimental works as well as from the literature.