Effect of oxygen ordering on bulk and thin film ceramic superconductors

The importance of oxygen doping in the high-Tc copper-oxides as a crucial parameter of superconductivity in these materials is emphasized, pointing out that changes in the oxygen content can induce structural transformations, metal-insulator transitions, and variations in the transition temperature, and can influence the critical current and field properties. The oxygen kinetics in YBa2Cu3O(x) is considered in detail, and it is pointed out that most research on the effect of oxygen stoichiometry has been performed in the YBa2Cu3O(x) system because of the presence of loosely bound and easily removeable oxygen in the Cu-O chains. Oxygen diffusion in bulk and thin film systems are discussed and the effects of the oxygen stoichiometry on the Tc and the perovskite structure are analyzed. 64 refs