Oxygen loading in second-generation high-temperature superconductor tapes

We report a study of oxygen loading in YBa2Cu3O7−δ coated conductors fabricated by metalorganic deposition. In situ X-ray diffraction experiments allowed the measurement of small changes in the c-axis lattice parameter during and after oxygen loading, and these changes could be correlated with the oxygen stoichiometry. The variation of the superconducting transition temperature and critical current density with oxygen loading state was explored, showing that the critical current density increases monotonically with increased oxygen loading. Optimum performance is therefore obtained by fully oxygen loading to an overdoped state.