This paper presents our latest experimental results on high-temperature superconducting (HTS) splice joints for HTS insert coils made of YBCO and Bi2223, that comprise a 1.3 GHz low-temperature superconducting/HTS nuclear magnetic resonance magnet currently under development at Francis Bitter Magnet Laboratory. HTS splice joint resistivity at 77 K in these insert coils must be reproducible and <; 100 Ω·cm2. Several YBCO tape to YBCO tape (YBCO-YBCO) splice joint samples were fabricated, and their resistivity and Ic were measured at 77 K. First, we describe the joint splicing setup and discuss the parameters that affect joint resistivity: pressure over joint surface, solder, and YBCO spool batch. Second, we report results on YBCO-YBCO joints at 77 K in zero field. Measurements have shown that spool batch and solder are primary sources of a wide range of variation in YBCO-YBCO joint resistivity. By controlling these parameters, we expect to reproducibly achieve HTS-HTS resistive joints of resistance <; 100 nΩ·cm2.

中文翻译：

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用于高场 LTS/HTS NMR 磁体的 YBCO 和 Bi2223 线圈：HTS-HTS 联合电阻率

本文介绍了我们对由 YBCO 和 Bi2223 制成的 HTS 插入线圈的高温超导 (HTS) 拼接接头的最新实验结果，该线圈包括目前在 Francis Bitter 磁体实验室正在开发的 1.3 GHz 低温超导/HTS 核磁共振磁体。这些插入线圈中 77 K 时的 HTS 拼接接头电阻率必须是可重复的并且 <; 100Ω·cm2。制作了几个 YBCO 带到 YBCO 带 (YBCO-YBCO) 拼接接头样品，并在 77 K 下测量了它们的电阻率和 Ic。首先，我们描述接头拼接设置并讨论影响接头电阻率的参数：接头表面的压力、焊料和 YBCO 线轴批次。其次，我们报告了 77 K 零场下 YBCO-YBCO 接头的结果。测量表明，线轴批次和焊料是 YBCO-YBCO 接头电阻率大范围变化的主要来源。通过控制这些参数，我们期望可重复地实现电阻 <; 的 HTS-HTS 电阻接头。100nΩ·cm2。