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 process a NdBCO seed crystal was used to promote heterogeneous nucleation, which allows the fabrication of single-grain YBCO containing a uniform and very fine distribution of Y-211 inclusions in the YBa₂Cu₃O_7−δ(Y-123) matrix without the addition of Pt. These superior microstructural features and significant field trapping ability compared with samples processed by conventional top-seeded melt growth suggest this technique could be a practical alternative for processing large, single-grain superconductors for engineering applications.