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

We employed Ba-Cu-O substrates for fabrication of bulk Y-Ba-Cu-O superconductors in the top-seeded melt-growth method. There were several advantages for a use of a Ba-Cu-O substrate compared to conventional substrate materials such as MgO, ZrO₂, Al₂O₃, RE123 and RE211 (RE rare earth). The Ba-Cu-O substrate avoided crystallization from a substrate, suppressed a liquid loss and then scarcely reacted with a precursor. Furthermore, the introduction of large-sized cracks into a grown bulk greatly was suppressed by propagating along the interface between a grown bulk and a substrate. We could obtain bulk Y-Ba-Cu-O superconductors with uniform trapped magnetic filed distributions and equal maximum trapped filed 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.