Lab Activities
Next-Generation Magnet Development Collaboration Unit
Research Activities
Unit Leader
Yoshinori Yanagisawa
Nuclear Magnetic Resonance (NMR) spectrometers enable structural analysis of a wide range of substances, including biological samples, polymers, nanomaterials, and natural products, by using strong magnetic fields. The analytical performance of NMR spectrometers improves with increasing magnetic field strength. Our laboratory conducts research and development on cutting-edge magnet technologies that integrate high-temperature superconductor (HTS) wires, coils, and joints, aiming at next-generation high-field magnets for NMR applications. Based on these technologies, we are pursuing the development of the world’s highest-field NMR magnet, as well as ultra-compact NMR magnets that operate without liquid helium, thereby contributing to medical and biological sciences through advanced analysis of biological samples.
In previous work, we demonstrated the generation of a 31.4 T ultra-high magnetic field using HTS coils energized in the background field of a low-temperature superconductor magnet, and successfully protected the innermost coil against quench. The coil survived owing to the self-protecting characteristics of the intra-layer no-insulation (LNI) method proposed in our laboratory. The complex quench behavior, accompanied by current bypassing within the winding, was analyzed using a custom-developed numerical simulator. These studies revealed that the bypass resistivity inside the winding plays a crucial role in quench protection. Parametric analyses indicated a required range of bypass resistivities of approximately 10–10,000 mΩ·cm for larger coils, posing a new challenge in the practical control of bypass resistivity in LNI windings.
In this context, we recently proposed the resistance-controlled (RC) interface method, which employs stainless-steel mesh and/or micropowders impregnated with epoxy as current-bypassing interface layers between REBCO tapes and copper sheets (Kawahata et al., IEEE Trans. Appl. Supercond. 35 (2025) 4702206). Although this approach is still at a preliminary stage for full-scale magnet applications, experimental studies have demonstrated its capability to achieve high and stable bypass resistivities with robustness against external disturbances.
Development of next-generation magnet technology.
In our laboratory, we fabricate electromagnet coils using high-temperature superconductor (HTS) tapes and energize them at cryogenic temperatures to evaluate their performance and physical properties. The experimental data are analyzed in conjunction with multiphysics simulations to elucidate the complex behavior of magnetic fields, voltages, and temperatures around and within the coils. Based on this foundational knowledge and these techniques, we develop NMR magnet systems and perform measurements on protein samples.
Recent Major Publications
Dang W, Muto Y, He F, Takahashi M, Tsuda K, Nagata T, Tanaka A, Kobayashi N, Kigawa T, Güntert P, Shirouzu M, Yokoyama S, Kuwasako K. 1H, 13C, and 15N resonance assignments and solution structure of the CID domain of SR-related- and CTD-associated factor 8 (SCAF8). Biomol NMR Assign 20, 7 (2025)
Invited Presentations
Yanagisawa Y, Yamazaki T, Kobayashi K, Piao R, Ueda K, Suetomi Y, Hamada M, Yokoyama S, Saito K, Nishijima G, Ueda H, Miyazaki H, Kiss T, Ono M. Development of a 1.3 GHz NMR magnet with REBCO superconducting joints under the JST-Mirai Program. Workshop on ultra-high-field solenoids, Geneva, Switzerland, Nov (2025)
M. Takahashi, Development and Industrial Applications of Single-Sided Open NMR Using High-Temperature Superconducting Bulk Magnets, Investigation Committee on Industrial Applications of High-Temperature Superconducting Bulk Materials, Online, Japan, Oct (2025) (presented in Japanese)
M. Takahashi, Development of Compact and Portable NMR Systems and Their Future Prospects, NMR Research Group, The Society of Polymer Science, Tokyo, Japan, May 9 (2025) (presented in Japanese)
Y. Yanagisawa, Current Status of the Development of Ultra-high-Field NMR Magnets Using REBCO Tapes, FY2025 Third Symposium of the Superconductivity Applications Research Group, Cryogenics and Superconductivity Society of Japan, Osaka, Japan, Dec. 11 (2025) (presented in Japanese)