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

Large domain YBa2Cu3O7-d/Y2BaCuO5 (YBCO) samples were prepared by top-seeded melt-textured process, with the addition of SnO2 and CeO2 or PtO2. In comparison to that in the CeO2-doped sample, the YBa2Cu3O7-d (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 (Jabc) and irreversibility fields. Enhancement of Jabc is related to microstructure inhomogeneity and core surface pinning. 8 refs.