Abstract The ability of single grain Y-Ba-Cu-O (YBCO) bulk superconductors to trap large magnetic fields is due generally to the presence of embedded, non-superconducting Y2BaCuO5 (Y-211) phase particles, in optimum amount, in the superconducting YBa2Cu3O7-δ (Y-123) phase matrix, which increases flux pinning and, hence, critical current density of the bulk material. The presence of smaller particles of Y-211 could be expected to improve further the superconducting properties of single grain, bulk YBCO samples, although the smallest Y-211 particles that have been engineered to date within the bulk microstructure are around 800 nm in size. It is extremely challenging to reduce the Y-211 particle size any further due to problems of particle agglomeration that originate, inevitably, from the effects of surface energy and reactivity at relatively high processing temperatures. In this work, we report a novel approach to the fabrication of Y-211 pinning centres in bulk YBCO superconductors in the form of nano-whiskers manufactured by a solution blow spinning technique. The Y-211 nano-whiskers, of which 62% were smaller than 500 nm, were added to the YBCO precursor powders to produce a single grain bulk sample by the buffer-aided top-seeded melt growth (BA-TSMG) processing technique. The resulting YBCO single grain, of diameter 20 mm, was able to trap a magnetic field of 0.63 T at 77 K with an associated critical current density of 3.9 × 104 A/cm2 in self-field. The results of this study demonstrate clearly that the use of Y-211 nano-whiskers is a promising route for enhancing flux pinning in bulk YBCO single-grains, which is potentially significant for the development of high field engineering applications.

中文翻译：

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通过溶液吹塑技术合成 Y2BaCuO5 纳米晶须并将其成功引入单晶 YBCO 体超导体

摘要 单晶粒 Y-Ba-Cu-O (YBCO) 体超导体捕获大磁场的能力通常是由于存在嵌入的非超导 Y2BaCuO5 (Y-211) 相粒子，其数量最佳，在超导 YBa2Cu3O7-δ (Y-123) 相基质，这增加了磁通钉扎，从而增加了大块材料的临界电流密度。Y-211 较小颗粒的存在有望进一步提高单颗粒、块状 YBCO 样品的超导性能，尽管迄今为止在块状微观结构中设计的最小 Y-211 颗粒的尺寸约为 800 nm。由于不可避免地产生的颗粒团聚问题，进一步减小 Y-211 颗粒尺寸极具挑战性，从表面能和反应性在相对较高的加工温度下的影响。在这项工作中，我们报告了一种在散装 YBCO 超导体中制造 Y-211 钉扎中心的新方法，该方法采用溶液吹塑技术制造的纳米晶须形式。将 Y-211 纳米晶须（其中 62% 小于 500 nm）添加到 YBCO 前驱体粉末中，以通过缓冲辅助顶部种子熔体生长 (BA-TSMG) 加工技术生产单颗粒散装样品。由此产生的 YBCO 单晶粒，直径为 20 毫米，能够在 77 K 下捕获 0.63 T 的磁场，在自场中相关的临界电流密度为 3.9 × 104 A/cm2。这项研究的结果清楚地表明，使用 Y-211 纳米晶须是增强散装 YBCO 单晶粒中通量钉扎的有希望的途径，