A strong enhancement of the critical current density was obtained in melt-textured Cu3Ba2YO7/Y2BaCuO5 composites by imposing a high (100bar) O pressure at 400C. Enhancement factors as high as 180% were found at low temperatures. Transmission electron microscopy revealed a high concentration of dendrite-like stacking faults which were generated as a result of the strongly non-equilibrium conditions of the transformation from Cu3Ba2YO7 to Cu4Ba2YO8. High concentrations of 1/6<031> partial

dislocations within the (001) planes were proposed to be point-defect pinning centers which could enhance the critical current density.

High Oxygen Pressure Generation of Flux-Pinning Centers in Melt-Textured YBa2Cu3O7. T.Puig, J.Plain, F.Sandiumenge, X.Obradors, J.Rabier, J.A.Alonso: Applied Physics Letters, 1999, 75[13], 1952-4