Top-seeded infiltration growth of Y-Ba-Cu-O bulk superconductors

A top-seeded melt-growth (TSMG) process is widely used to fabricate single domain YBa2Cu3Oy (Y-Ba-Cu-O) bulk superconductors. Pores are often found in the TSMG-processed Y-Ba-Cu-O samples due to the oxygen gas evolution during the molten stage. Recently developed liquid infiltration growth (LIG) process is known to be effective in suppressing the pore evolution and in refining the size of Y2BaCuO5 (Y211) particles dispersed in YBa2Cu3Oy matrix. The LIG process utilizes the liquid (Ba3Cu5O8) infiltration into a pre- sintered Y211 contact and slow cooling through a peritectic temperature. In this study, we fabricated bulk Y-Ba-Cu-O superconductors by the LIG process combined with top-seeding with SmBa2Cu3Oy seed and confirmed that a single-domain bulk can be produced. Trapped field measurements however showed that some distortion in the field distribution was observed in the region near the seed crystal, which was attributed to Y211 density and its relatively large size.