Interaction mediated by size differences between Y2BaCuO5 and CeO2 particles in melt-textured YBCO superconductors

The Refining of Y2BaCuO5 (Y211) is crucial in the fabrication of YBa2Cu3Ox (Y123) bulk superconductors with a high critical current density (Jc) for power engineering applications.In this work, the influence of an addition of Y211 and CeO2 of different sizes on the Y211 refinement and superconducting properties of melt-textured Y123 superconductors is investigated. Nano-size Y211 and nano-size CeO2 were prepared by attrition-milling (250 rpm and 2 h). Using mixed powders consisting of 85 wt.% Y123, 15 wt.% Y211, and 1 wt.% CeO2, Y123 quasi-single crystals were fabricated via a top seed melt-textured growth process. The interaction between Y211 and CeO2 of different particle sizes was examined in terms of the size, uniformity and density of the Y211 particles that existed in the melt-textured samples. The reaction between the nano-size Y211 and the nano-size CeO2 was more violent due to the more frequent collisions compared to the other reactions (micro-size Y211/nano-size CeO2 or micro-size Y211/micro-size CeO2), resulting in the most effective for refinement of Y211 particles and the best Jc value of 4.2 × 104 (A/cm2) (at 77 K and a zero-field).