Influence of Sm2O3 and La2O3 Additions on the Microstructure and Properties of YBCO Bulk Superconductors Prepared by TSIG Process

Single-grain YBa2Cu3O7-x (YBCO, Y123) bulk superconductors were prepared by infiltration growth process. Instead of commonly used Y211 powder, the solid-phase precursor was prepared by solid-state synthesis from Y2O3+BaCuO2. The samples with synthesized solid phase have optimal porosity supporting oxygenation process and finer Y2BaCuO5 (Y211) particles in Y123 matrix as shown by Vojtkova and Diko. The samples without dopant and with Sm2O3 or La2O3 additions to solid-phase precursor were also prepared. Samarium or lanthanum dopants were used to substitute yttrium and barium atoms and to involve the chemical pinning. The influence of used additions to the bulk superconductors on microstructure, transition temperature and critical current density at 77 K was studied.