Article
Physics, Applied
Y. Takeda, K. Kobayashi, A. Uchida, H. Kitaguchi, G. Nishijima, Y. Yanagisawa, T. Nakashima, S. Yamade, S. Kobayashi, T. Kato, S. Nakamura, T. Motoki, J. Shimoyama
Summary: By introducing a two-step sintering process, we have improved the critical current of the superconducting joint between Bi2223 tapes, and successfully demonstrated its in-field transport and ultra-low in-field resistance. This study provides an important technological foundation for the development of Bi2223 superconducting magnets.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Shintetsu Kanazawa
Summary: Through the use of non-congruent melting method, a successful development of superconducting joints between Bi2223 tapes was achieved in the study. Utilizing a multi-junction approach with stepped structure boundaries proved to increase contact area and critical current of the joint.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2021)
Article
Engineering, Electrical & Electronic
Weican Huang, Xiaohua Jiang, Peng Xue, Hangyin Mao, Yuguang Sun
Summary: This study investigates the current distribution and degradation of Bi2223 tapes in the superconducting DC energy pipeline under different voltage levels, revealing that the currents tend to flow closer to the cable of opposite polarity. The impact of magnetic fields on the critical current density of the cable shows similar degradation levels across different insulation distances between poles.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2021)
Article
Chemistry, Multidisciplinary
David Collomb, Min Zhang, Weijia Yuan, Simon J. Bending
Summary: The study used scanning Hall probe microscopy to investigate vortex patterns in commercial GdBaCuO tapes, revealing highly disordered vortices pinned by nanoscale Gd2O3 inclusions. The broad vortex profiles, with little temperature dependence, suggest disruption of supercurrents due to high density of nanoscale pinning sites. Measurements also indicate rapid relaxation of critical state profiles by flux creep, providing important insights into the enhancement of critical current in these tapes.
Article
Materials Science, Multidisciplinary
Chunjiang Guo, Xin Yu, Yue Wu, Dean Liu, Mengru Zhao, Wei Wu, Jiamin Zhu, Zhijian Jin, Yue Zhao
Summary: This study tested the aging of copper stabilizers on second-generation high-temperature superconducting tapes, finding that aging increased the surface contact resistivity and decreased the purity of the copper stabilizer. The study also identified Cu2O as the main product on the tape surface during reactions with oxygen and water vapor.
MATERIALS CHARACTERIZATION
(2023)
Article
Materials Science, Multidisciplinary
Shifa Liu, Chao Yao, He Huang, Chiheng Dong, Wenwen Guo, Zhe Cheng, Yanchang Zhu, Satoshi Awaji, Yanwei Ma
Summary: The development of high-field magnets relies heavily on the performance of superconducting materials. Iron-based superconductors show promise for high-field applications, with Cu/Ag composite-sheathed Ba122 superconducting tapes achieving practical-level critical current density. By manipulating grain texture through rolling and densification, the transport properties of the tapes can be enhanced.
SCIENCE CHINA-MATERIALS
(2021)
Article
Chemistry, Physical
Chunjiang Guo, Yue Wu, Wei Wu, Zili Zhang, Jiangtao Shi, Sikan Chen, Jiamin Zhu, Yawei Wang, Zhijian Jin, Qiuliang Wang, Yue Zhao
Summary: In this study, the electro-mechanical behaviors of laminated 2 G-HTS tapes were investigated through experimental and theoretical analysis. The results showed that the laminated tapes had higher irreversible tensile strains and improved electro-mechanical properties compared to the copper-plated tapes.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Physics, Applied
He Huang, Chao Yao, Chiheng Dong, Xianping Zhang, Dongliang Wang, Shifa Liu, Zhe Cheng, Yanchang Zhu, Yanwei Ma
Summary: Using the EBSD technique, the microstructure of hot-pressed (HP) and flat-rolled (FR) Ba-122 tapes was analyzed. The results indicated that HP tapes exhibited better texture and grain connectivity, while FR tapes had smaller grain size. It is recommended to find a balance point that promotes grain orientation and maintains moderate grain size to improve the transport properties of IBS tapes further.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
Qixun Zhou, Shuo Chen, Qian Guo, Tao Su, Jiayi Wang, Yufeng Zhang
Summary: In this paper, a 2D simulation model of stacked high-temperature superconducting tapes was established, and the effects of different stacking conditions on AC loss characteristics were investigated. It was found that the magnetization loss of stacked tapes is positively related to the number of stacked layers and the spacing between tapes, while the transport loss decreases with the increase of the number of stacked layers.
JOURNAL OF ELECTRONIC MATERIALS
(2023)
Article
Physics, Applied
Junjie Jiang, Heng Wang, Yajun Jia, Jie Sheng, Yawei Wang, Zhuyong Li, Yue Zhao, Zhiyong Hong, Kyungwoo Ryu, Zhijian Jin
Summary: The combination of distributed temperature sensing system and optical fiber-encapsulated HTS tape shows promise for fast and accurate quench detection. Simulation and experimental results suggest that the embedded optical fibers have minimal impact on the original characteristics of the HTS tape, and the fabricated OFE-HTS tape exhibits good performance.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Hiroyuki Yamada, Yuji Tsuchiya, Yutaka Yoshida, Toshiyuki Mito, Yuta Onodera, Naoki Hirano
Summary: This study proposes a method to improve the stability of conductors by fabricating conductive micro-paths for current sharing between REBCO tapes. The experimental results show that in REBCO conductors with conductive micro-paths, the current can bypass the damaged areas.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2022)
Article
Physics, Applied
Wanshuo Sun, Yaohui Wang, Zili Zhang, Xiaolong Zhang, Lei Wang, Junsheng Cheng, Hongli Suo, Qiuliang Wang
Summary: In this study, a NbTi-Bi2223 hybrid low-resistive joint fabricated by the superconducting solder method was systematically investigated. The joint resistance and current capability under different applied magnetic fields were measured, and the resistance exhibited a near-linear relationship with the applied field. Beyond the superconducting properties, the allowed mechanical criteria for the Bi2223 tape in the joint were also briefly studied. A 1.3 GHz NMR design with a NbTi-Bi2223 hybrid low-resistive joint was shown as an application demonstration based on the above two properties. The attempt to obtain a lower resistance value by extending the joint length was unsuccessful, and the main source of resistance in NbTi-Bi2223 was studied. We aim to present an engineering-feasible NbTi-Bi2223 hybrid low-resistive joint to help improve the development of GHZ NMR.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2023)
Article
Physics, Applied
Yongqiang Peng, Zhigang Zeng, Difan Zhou, Wenwen Zhao, Zhuoyue Jia, Yanqun Guo, Chuanyi Bai, Feng Fan, Yangyang Chen, Chuanbing Cai
Summary: The study shows that joint-free superconducting annular disks and their stacks can achieve high shielding factors for efficient magnetic shielding applications, with the shielding factor having a linear relationship with the ratio of the outer and inner diameter of the disk.
JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM
(2021)
Article
Engineering, Electrical & Electronic
Bruno de Sousa Alves, Marc Laforest, Frederic Sirois
Summary: This article presents a new 3-D thin-shell model for electromagnetic modeling of arbitrary HTS tape configurations. The model can accurately calculate nonuniform current distributions and losses, while reducing computational burden.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2022)
Article
Energy & Fuels
Alireza Sadeghi, Zhihui Xu, Wenjuan Song, Mohammad Yazdani-Asrami
Summary: In this study, an artificial intelligence technique based on artificial neural networks (ANN) was proposed to estimate the probability of quenches in high-temperature superconducting (HTS) tapes caused by weak points. The model can be used to estimate the probability of quenches under different operating temperatures and currents for different types of HTS tapes.
Article
Physics, Applied
T. Motoki, Y. Yanai, K. Nunokawa, S. Gondo, S. Nakamura, J. Shimoyama
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2020)
Article
Physics, Applied
Takanori Motoki, Yanai Yu, Kota Nunokawa, Jun-ichi Shimoyama
APPLIED PHYSICS EXPRESS
(2020)
Article
Physics, Applied
Yasuaki Takeda, Taketo Iwami, Yujin Saito, Takanori Motoki, Jun-ichi Shimoyama
Summary: In order to achieve practical superconducting joints between Bi2223 tapes for persistent-current magnets, high critical current density (Jc) Bi2223 thick films suitable for joint intermediate layers are needed. Despite the effectiveness of magnetic grain alignment technique for Bi2223 materials, successful studies in obtaining high intergrain Jc of Bi2223 polycrystalline materials prepared through magneto-scientific method have not been reported. This study demonstrated the improvement of intergrain Jc in Bi2223 thick films through magnetic grain alignment, showing promise for practical superconducting joints between Bi2223 commercial tapes.
PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS
(2021)
Article
Physics, Applied
Y. Suetomi, T. Yoshida, S. Takahashi, T. Takao, G. Nishijima, H. Kitaguchi, Y. Miyoshi, M. Hamada, K. Saito, R. Piao, Y. Takeda, H. Maeda, Y. Yanagisawa
Summary: This paper presents experimental and simulated results on the quench of an intra-layer no-insulation (RE: rare earth)Ba2Cu3O7-delta (REBCO) coil in a 31.4 T central magnetic field. The study shows that high electrical contact resistivity plays an important role in protecting the coil during the quench process.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2021)
Article
Physics, Applied
Y. Takeda, K. Kobayashi, A. Uchida, H. Kitaguchi, G. Nishijima, Y. Yanagisawa, T. Nakashima, S. Yamade, S. Kobayashi, T. Kato, S. Nakamura, T. Motoki, J. Shimoyama
Summary: By introducing a two-step sintering process, we have improved the critical current of the superconducting joint between Bi2223 tapes, and successfully demonstrated its in-field transport and ultra-low in-field resistance. This study provides an important technological foundation for the development of Bi2223 superconducting magnets.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2022)
Review
Physics, Applied
Y. Takeda, H. Maeda, K. Ohki, Y. Yanagisawa
Summary: This article analyzes the temporal magnetic field drift and fluctuations observed in MRI and NMR magnets operating in the driven mode, and explores effective methods for stabilizing the temporal magnetic field fluctuations. In the past decade, significant progress has been made in superconducting joints between high-temperature superconductors, enabling the development of persistent-mode ultra-high field magnets.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2022)
Article
Physics, Applied
Takanori Motoki, Rempei Sasada, Takuma Tomihisa, Masaya Miwa, Shin-ichi Nakamura, Jun-ichi Shimoyama
Summary: By using a single-direction melt growth method, we have successfully fabricated textured bulks of various shapes and sizes with high reproducibility and excellent superconducting properties.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Y. Takeda, Y. Suetomi, U. Nakai, R. Piao, Y. Matsutake, T. Yagai, T. Motoki, J. Shimoyama, M. Hamada, K. Saito, Y. Yanagisawa
Summary: The authors developed and operated a persistent current mode LTS/Bi-2223 NMR magnet using a Bi-2223 insert coil with a superconducting joint. They successfully demonstrated a PC mode operation of the magnet at 9.39 T, with low field drift rate and estimated joint resistance. This is an important step towards full-scale PC mode Bi-2223 magnets.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2022)
Article
Engineering, Electrical & Electronic
Takanori Motoki, Masaya Miwa, Mirei Semba, Jun-ichi Shimoyama
Summary: The effects of high-temperature post-annealing on the magnetic field-trapping properties of REBa2Cu3Oy melt-grown bulks were investigated. The post-annealing greatly improved the trapped fields and accelerated oxygen diffusion in the bulks. The trapped field enhancement ratio averaged over all bulks was about 40%, and a DyBa2Cu3Oy bulk recorded a high trapped field of 1.09 T at 77 K.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2023)
Article
Physics, Applied
Y. Takeda, G. Nishijima, K. Inoue, Y. Takano, H. Kitaguchi
Summary: This study quantitatively investigated the effect of intermediate layer densification on the critical current (Ic) of Bi-2223 superconducting joints. The results showed that pressing the film samples to increase density can enhance the intergrain critical current density (Jc). Additionally, synthesizing an intermediate layer between two Bi-2223 tapes with uniform uniaxial pressure resulted in reproducible superconducting joints with high Ic.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2023)
Article
Physics, Applied
Takanori Motoki, Mirei Semba, Jun-ichi Shimoyama
Summary: Ring-shaped REBa2Cu3Oy melt-textured bulks with high trapped field and uniform superconducting properties were successfully grown using the single-direction melt growth method. The study achieved the highest trapped field value of 1.84 T at 77 K among reported ring-shaped bulks, along with concentrically cone-shaped trapped field distribution. These findings demonstrate significant advancement in the fabrication of high-quality bulks for various magnetic applications.
APPLIED PHYSICS EXPRESS
(2023)
Article
Engineering, Electrical & Electronic
Yasuaki Takeda, Gen Nishijima, Kensuke Kobayashi, Hitoshi Kitaguchi
Summary: Superconducting joints between Bi-2223 tapes were fabricated using a hot-pressing process and a 24-hour heat treatment. Specialized equipment was developed to apply pressure during the heat treatment. Hot pressing yielded practical critical current even with a short heat treatment. The resistance of the superconducting joint in a closed-loop was measured at 7.3 x 10(-15) ? at 4.2 K, with an estimated maximum persistent current flow of 170 A at 4.2 K. Remaining challenges include purification and densification of the intermediate layer in the joint. Once these challenges are addressed, the hot-pressing process shows promise for high-yield fabrication of high-performance Bi-2223 superconducting joints in a short processing time.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2023)
