Reliable single grain growth of (RE)BCO bulk superconductors with enhanced superconducting properties
Reliable single grain growth of (RE)BCO bulk superconductors with enhanced superconducting properties
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DOI：
10.1088/1361-6668/ab627d
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发表时间：
2020-01-01
影响因子：
3.6
通讯作者：
Numburi, Devendra K.
中科院分区：
文献类型：
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作者：
Cardwell, David A.;Shi, Yunhua;Numburi, Devendra K.
综述了三种主要工艺方法：顶籽晶熔体生长(TSMG)、顶籽晶浸渗生长(TSIG)以及TSMG和TSIG相结合的工艺路线制备大晶(RE)BCO和(RE)BCO-Ag块体高温超导体的研究进展。近年来，为了可靠地生长(RE)BCO单晶并提高其超导性能，对这些工艺路线进行了一些重大而有用的修改。对于(RE)BCO单晶的可靠生长，我们进一步发展了可靠播种的所谓缓冲技术，包括在球团底部识别和提供合适的富液相。事实证明，这一改进对于这里介绍的新开发的制造技术的成功至关重要。此外，我们还通过控制单晶材料的微观结构(特别是孔隙率和RE-211分布)和抑制晶体生长过程中RE/BA的替代程度，解决了在改善块体样品超导性能方面存在的重大挑战。最后，我们简要总结了在不久的将来实现这些具有重要技术意义的材料的实际应用的潜在途径。
We review recent progress in the successful and reliable fabrication of large grain (RE)BCO and (RE)BCO-Ag bulk high temperature superconductors by three primary processing methodologies: top-seeded melt growth (TSMG), top-seeded infiltration growth (TSIG) and a combined processing route comprising both TSMG and TSIG. Several significant and useful modifications have been made to these processing routes over the recent years in order to grow (RE)BCO single grains reliably and to enhance their superconducting properties. With respect to the reliable growth of (RE)BCO single grains, we have further developed the so-called buffer technique for reliable seeding, which includes identifying and providing an appropriate liquid-rich phase at the bottom of pellet. This modification has proved to be critical to the success of the newly-developed fabrication techniques presented here. In addition, we have addressed existing and significant challenges in the context of improving the superconducting properties of the bulk samples by controlling the microstructures of single grain materials (porosity and the RE-211 distribution, in particular) and by suppressing the extent of RE/Ba substitution during grain growth. Finally, we provide a short summary of the potential pathways towards realising practical applications of these technologically important materials in the near future.