Microstructure and superconductivity of the melt-textured YBCO grown with the addition of SnO2

Large domain YBa2Cu3O7-delta/Y2BaCuO5 (YBCO) samples were prepared by top-seeded melt-textured process, with the addition of SnO2 and CeO2 or PtO2. It was found that, in comparison to that in the CeO2-doped sample, the YBa2Cu3O7-delta (123) matrix was twisted in the PtO2-doped sample and its Y2BaCuO5 (211) particles were larger on average and less homogeneously distributed. The PtO2-doped sample showed a more obvious second-peak effect, and higher values of a-b plane critical current density (J(c)(ab)) and irreversibility fields (B-irr). The enhancement of J(c)(ab) is related to the microstructure inhomogeneity and the core surface Delta kappa pinning.