Effects of barium titanate and titania additions on the microstructure andcritical current density of yttrium barium cuprate ceramics

Fine-particle BaTiO3 and TiO2 additions are shown to have a significant eff ect on the structure, microstructure, and superconducting properties of YBa 2Cu3O7-delta ceramics prepared via partial melting. The ranges of solid sol utions are determined. The additions are found to enhance the critical curr ent density by a factor of 1.5-2.5. X-ray microanalysis of individual grain s in the doped ceramics indicates an increased concentration of small inclu sions, presumably Y2BaCuO5, embedded in superconducting grains and acting a s pinning sites.