Fabrication of large single-grain Y-Ba-Cu-O through infiltration and seeded growth processing

Large, single-grain Y-Ba-Cu-O (YBCO) was fabricated via the infiltration of Ba-Cu-O liquid into a precursor body composed of solid, porous Y2BaCuO5 (Y -211) and observed to trap a magnetic field of 0.15 T at 77 K. In this proc ess a NdBCO seed crystal was used to promote heterogeneous nucleation, whic h allows the fabrication of single-grain YBCO containing a uniform and very fine distribution of Y-211 inclusions in the YBa2Cu3O7-delta (Y-123) matri x without the addition of Pt. These superior microstructural features and s ignificant field trapping ability compared with samples processed by conven tional top-seeded melt growth suggest this technique could be a practical a lternative for processing large, single-grain superconductors for engineeri ng applications.