Improvement of critical current in superconducting detachable joint for high-resolution micro MRI

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K04584
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 21050:Electric and electronic materials-related
• Research Institution: Yonago National College of Technology
• Principal Investigator: Tanaka Hiromi 米子工業高等専門学校, その他部局等, 教授 (60511491)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 電子・電気材料 / 解析・評価

Outline of Final Research Achievements

In this research, we focused on improving critical current in Bi-based high-temperature superconducting (Bi-based HTS) joint. To fabricate the Bi-based HTS joint, we adopted simple method named “pressing method” for connecting between two Bi-based HTS conductors. In advance of the pressing method, we mechanically pealed a supporting Ni-alloy layer. We named the pealing method as “mechanically pealing method”.
As a result, we found that the mechanically pealing method is useful to reduce the chemically damaged layer at interface between two Bi-based HTS conductors. In addition, we succeeded in producing Bi-based HTS conductors’ joints which have superconducting transition of 109K. The superconducting transition value is same as the one of original Bi-based HTS conductor. These results indicate that our new method is useful to produce the Bi-based HTS conductors’ joint with good superconducting properties.

Free Research Field

電気電子材料工学

Academic Significance and Societal Importance of the Research Achievements

高分解能μMRIは関節リウマチの早期発見など、幅広い分野での利用が可能であり世界中で研究が進められている。特に分解能100μm以上の高分解能μMRIは、コイル化し易いBi系高温超伝導線材をパンケーキ状に巻いて作製する。コイル間をゼロ抵抗で接続する必要があるが、現状では接合部の超伝導特性が低いという問題がある。本研究では、この接合部の超伝導特性を改善するため、補強材を非加熱で機械的に取り除く手法および圧着法の導入を行った。その結果、優れた高温超伝導接合を得ることに成功した。本研究の進展により、高分解能μMRIの実用化が促進され、先端医療診断を安価に受けられる社会の実現に寄与できたと考えている。