Homogenizing field-trapping capabilities of bulk Y-Ba-Cu-O superconductors fabricated using Ba-Cu-O oxide substrates for practical applications

We employed Ba - Cu - O substrates for fabrication of bulk Y - Ba - Cu - O superconductors using the top- seeded melt- growth method. There were several advantages of using a Ba - Cu - O substrate as compared to conventional substrate materials such as MgO, ZrO2, Al2O3, RE123 ( RE = rare earth) and RE211. The Ba - Cu - O substrate avoided crystallization from the substrate, suppressed liquid loss and scarcely reacted with the precursor. Furthermore, the introduction of large- sized cracks into a grown bulk was greatly suppressed by propagation along the interface between the grown bulk and the substrate. We were able to obtain bulk Y - Ba - Cu - O superconductors with uniform trapped magnetic field distributions and equal maximum trapped field values on both top and bottom surfaces, which indicates that the field- trapping capabilities were homogenized along the c- axes of the bulks fabricated on the Ba - Cu - O substrates.