Article
Engineering, Electrical & Electronic
Noriko Chikumoto, Satarou Yamaguchi, Oleg Shyshkin
Summary: By mapping the magnetic field data of three components, transport current profiles at the solder joint area of GdBCO tapes were successfully obtained, revealing a non-uniform current distribution at the joint edge. It is essential to carefully inspect both joint resistance and current distribution based on this observation.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2021)
Article
Physics, Applied
Y. Takeda, G. Nishijima, U. Nakai, T. Motoki, J. Shimoyama, H. Kitaguchi
Summary: This study systematically evaluates the angular dependence of resistance and critical current of a Bi-2223 superconducting joint in a closed-loop sample using a joint resistance evaluation system. The results show that the resistance and critical current of the joint depend on the angle of the magnetic field, and exhibit different characteristics in different angle ranges.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2023)
Article
Physics, Applied
Jing Zhang, Shaotao Dai, Tao Ma, Yan Li, Darui He
Summary: This study presents a new resistance-inductance type SFCL using the structure of the inductive superconducting coils, successfully studying the current limiting and inter-turn insulation characteristics. Simulation results show that the inductive superconducting coils can significantly reduce the fault current rise rate by more than 42% compared to non-inductive coils. By calculating the voltage and electric field distribution, important insights for insulation design are provided.
PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS
(2022)
Article
Physics, Applied
Hui Yu, Jeremy Levitan, Jun Lu
Summary: This study introduces a superconducting transformer (SCT) installed on a 12 T split solenoid magnet for testing the critical current of NbTi Rutherford cable. The accuracy of critical current measurement using SCT is discussed through calibration and comparison of results. The commissioning of SCT combined with the 12 T split magnet provides a unique cable testing capability for future cable development for the NHMFL and its users.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
M. Ohsugi, T. Yoshida, Y. Iijima, K. Kakimoto, W. Hirata, S. Fujita, M. Daibo, M. Furuse, Y. Yoshida
Summary: This study investigated the deposition of Ag-doped REBCO films using the hot-wall pulsed laser deposition method on Hastelloy tapes and evaluated the joint resistances of lap or bridge joints made by soldering. The results showed that the joint resistances were low and a double layer structure with a thin Ag-doped REBCO film on a high-Ic REBCO film exhibited good joint performance.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2022)
Article
Engineering, Electrical & Electronic
Gang Qian, Longbiao Wang, Yingying Lv, Mingyang Wang, Zhuyong Li, Zhiyong Hong, Zhijian Jin
Summary: This study focuses on numerically investigating the performance of different types of encapsulated joints, categorizing them into two types and utilizing a nonlinear circuit model for analysis and experiments to determine parameters. Discussions on resistance performances of the encapsulated joints and HTS tape arrangements are conducted to achieve minimum resistances.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2021)
Article
Engineering, Electrical & Electronic
Yanjun Chen, Zihao Wang, Boyang Shen, Bin Wang, Jie Sheng
Summary: This paper focuses on the optimal configuration of ISFCL designed for distribution networks, establishing the optimal model of ISFCL parameters for selecting suitable parameters. The results are used to guide the design and fabrication of ISFCL prototypes.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2021)
Article
Physics, Applied
Yasuaki Takeda, Yuji Tsuchiya, Gen Nishijima
Summary: A low circuit resistance is necessary for a superconducting magnet operated in persistent mode with superconducting joints. We conducted current decay measurements on a high-temperature superconducting closed loop, and determined that the joint resistance is inversely proportional to time. This finding contributes to achieving low circuit resistance.
APPLIED PHYSICS EXPRESS
(2023)
Article
Engineering, Electrical & Electronic
Nobuya Banno, Kensuke Kobayashi, Akira Uchida, Hitoshi Kitaguchi, Akiko Takenouchi, Makoto Watanabe
Summary: A novel superconducting joint method using high-temperature-tolerable (HTT) superconducting Nb-alloy intermedia has been developed to establish superconducting joints between NbTi and Nb3Sn wires, with ultra-low resistance and high success rate. However, there is a large scattering of I-c in the joints between NbTi and HTT Nb-alloy, possibly due to the cracking of NbTi filaments.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2022)
Article
Physics, Applied
Wanshuo Sun, Shunzhong Chen, Junsheng Cheng, Qiuliang Wang
Summary: NbTi-Nb3Sn-NbTi superconducting joints were fabricated by resistive welding, and an X-ray 3D microscopic imaging system was used to evaluate the microstructure and connecting status without destroying the joints. The microstructure and grain orientation maps of the Nb3Sn bulk in the joints were tested by electron backscatter diffraction. The Nb3Sn phase exhibited random orientation, and the grain boundaries were mainly composed of high-angle grain boundaries. The resistance of the joints was evaluated under different background fields, and the resistance was found to be 3 x 10(-13) & omega; under a 3 T background field.
JOURNAL OF LOW TEMPERATURE PHYSICS
(2023)
Article
Physics, Applied
T. Matsushita, M. Kiuchi, G. Nishijima, T. Masuda, S. Mukoyama, Y. Aoki
Summary: The critical current of a coaxial cable made of Bi-2223 tapes was investigated to address resistive voltage issues caused by current transfer, aiming to standardize the test method for superconducting AC power cables. Theoretical examination of current transfer in the outer shield layer was conducted, and resistive components in measured voltages were calculated to accurately determine critical current. Comparisons were made between calculated results and observed results to validate the methodology.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2021)
Article
Engineering, Electrical & Electronic
Nitin Bairagi, Vipul L. L. Tanna, Hiren Nimavat, Dashrath Sonara, Rohitkumar Panchal, Atul Garg, Gaurang Mahesuria, Rakeshkumar Patel, Dikens Christian, Pradip Panchal, Gaurav Purwar, Upendra Prasad, Raju Daniel
Summary: A conduction-cooled, high-temperature superconductor current lead has been developed, allowing operation up to 80K and saving cryogenic capacity in superconducting magnets. The lead utilizes commercially available rare earth cuprate oxide superconductor tapes and magnesium diboride for joints. Experimental results show promising performance of the lead.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2023)
Article
Engineering, Electrical & Electronic
Kensuke Kobayashi, Gen Nishijima, Kotaro Ohki, Tatsuoki Nagaishi, Akira Uchida, Hitoshi Kitaguchi
Summary: We evaluated the joint resistance and current-carrying capacity of the intermediate grown superconducting (iGS) joint at low temperatures and high magnetic fields using a specially developed evaluation system. The results showed that the iGS joint has a sufficiently high current-carrying capacity at 4.2K in a 3T magnetic field and does not exhibit magnetic field dependence. However, at 77K, the joint resistance was relatively high due to a high load factor.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2022)
Article
Physics, Applied
Zili Zhang, Xing Huang, Chunyan Cui, Hao Wang, Feifei Niu, Yuan Zhang, Xiangdong Kong, Li Han, Lei Wang, Xinning Hu, Qiuliang Wang
Summary: This paper presents a novel Nb superconducting joint with an ultralow resistance, fabricated using the electron beam welding (EBW) method. The EBW Nb joint has a resistance nearly one magnitude lower than conventional pressing joints, making it suitable for applications in fields requiring extremely low drift rates such as superconducting gravimeters. The EBW method could be one of the most promising joint fabrication methods for achieving maximum stability.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2022)
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
Physics, Applied
G. A. B. Matthews, J. Liu, C. R. M. Grovenor, P. S. Grant, S. Speller
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2020)
Article
Physics, Applied
G. A. B. Matthews, S. Santra, R. Ma, C. R. M. Grovenor, P. S. Grant, S. C. Speller
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2020)
Article
Materials Science, Multidisciplinary
Kenji Nawa, Demie Kepaptsoglou, Arsham Ghasemi, Philip Hasnip, Guillermo Barcena-Gonzalez, Giuseppe Nicotra, Pedro L. Galindo, Quentin M. Ramasse, Kohji Nakamura, Susannah C. Speller, Balati Kuerbanjiang, Thorsten Hesjedal, Vlado K. Lazarov
Summary: The study demonstrates that the weak van der Waals adhesion between Bi2Te3 and Ge can be overcome by forming an additional Te layer at their interface. First-principles calculations show that the formation of the additional Te layer is energetically favorable due to the strong hybridization between Te and Ge.
PHYSICAL REVIEW MATERIALS
(2021)
Article
Physics, Applied
W. Iliffe, N. Peng, G. Brittles, R. Bateman, R. Webb, C. Grovenor, S. Speller
Summary: An apparatus was constructed for irradiation and electrical testing of REBCO coated conductors below their critical temperature. The study observed the superconducting performance of samples before and after annealing, comparing irradiation at different temperatures to understand the effect on material properties. Results showed degradation of critical temperature and critical current density with irradiation dose, but significant recovery was seen after room temperature annealing, impacting the design of high temperature superconducting magnets for fusion reactors.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2021)
Article
Physics, Applied
D. A. Moseley, G. A. B. Matthews, D. Zhou, V Cientanni, Y. Tsui, M. D. Ainslie, S. Speller, J. H. Durrell
Summary: By studying the flux density during PFM in MgB2 bulk superconductors, improvements in cooling architecture were found to increase flux trapping capabilities and alter flux motion. These enhancements resulted in the largest trapped field for a single MgB2 bulk sample magnetized by a solenoidal pulsed field magnet.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
Tayebeh Mousavi, Yunhua Shi, John Durrell, Chris Grovenor, Susannah Speller
Summary: Bulk rare earth-Ba-cuprate superconductors have the potential to generate high-strength trapped magnetic fields, and the choice of rare earth element plays a crucial role in the growth and microstructure of single grains.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2022)
Article
Physics, Applied
G. A. B. Matthews, T. Mousavi, S. Santra, C. R. M. Grovenor, P. S. Grant, S. Speller
Summary: This study investigates a new processing method to improve the connectivity of ex-situ MgB2 bulks at low sintering temperatures. The addition of Mg enhances density and reduces MgB4 content, leading to improved sintering results and enhanced superconducting properties.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2022)
Article
Materials Science, Multidisciplinary
Stephen J. Turrell, Stefanie Zekoll, Junliang Liu, Chris R. M. Grovenor, Susannah C. Speller
Summary: A radio frequency magnetron sputter deposition process was developed for the low-cost, high-rate fabrication of LiCoO2 (LCO) thin films. The process involved systematically changing key parameters to increase deposition rate while maintaining structural and electrochemical properties. The resulting cathodes showed high discharge capacities and cycling performance, making them suitable for various applications.
Article
Physics, Applied
D. A. Moseley, D. P. Wilkinson, T. Mousavi, A. R. Dennis, S. Speller, J. H. Durrell
Summary: A new methodology in bulk MgB2 ring production for small-scale magnetic shielding or bench-top nuclear magnetic resonance systems is reported. This modified field-assisted sintering technique (mFAST) allows for direct formation of the rings without the need for machining or additives. The study found that individual rings can trap magnetic fields up to 1.24 T at 20 K, and multiple rings stacked together can achieve a trapped field of 2.04 T and a maximum shielded field of 1.74 T at 20 K. However, flux jumps remain a significant issue limiting performance at low temperatures, even with slow ramp rates.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2022)
Article
Physics, Applied
Zilin Gao, Sangeeta Santra, Chris R. M. Grovenor, Susannah C. Speller
Summary: The addition of hexagonal and cubic boron nitride can enhance the superconducting performance of MgB2 without reducing the superconducting transition temperature. Hexagonal boron nitride nanoparticles mixed with MgB2 powder easily react to produce Mg-N-B impurities, while larger cubic boron nitride particles do not. Adding 1 wt% hexagonal boron nitride or 5 wt% cubic boron nitride, after 6 hours of milling, has been shown to improve the critical current density of MgB2 over the entire magnetic field range.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2022)
Article
Physics, Applied
Y. Shi, T. Mousavi, A. R. Dennis, M. D. Ainslie, S. C. Speller, C. R. H. Grovenor, J. H. Durrell, D. A. Cardwell
Summary: This paper systematically investigates the distribution of J(c)-B along a vertical cross-section and the facet line of a seed crystal in a Gd-Ba-Cu-O sample at 77 K. The results show that the J(c)-B at the facet line is more than 10% higher than that at the seed for applied fields between 0.2 T and 2.5 T. The study also demonstrates that a more uniform trapped magnetic field can be achieved by optimizing the arrangement of individual GdBCO single grains.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2022)
Article
Physics, Applied
Canan Aksoy, Bakiye Cakir, Ezgi Taylan Koparan, Cemaleddin Simsek, Engin Tirasoglu, Susannah Speller, Chris R. M. Grovenor, Tevfik Kucukomeroglu, Ekrem Yanmaz
Summary: Researchers have found that adding materials such as Pb, Nb, AgCu and graphene nano pellets into SnIn (35:65) can enhance its superconducting properties. Even low Pb additions show a dramatic improvement in superconducting properties and could potentially replace commonly used PbBi solder with better results.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2023)
Article
Physics, Applied
Zilin Gao, Chris R. M. Grovenor, Susannah C. Speller
Summary: The microstructure of polycrystalline MgB2 significantly affects its current carrying ability, with grain boundaries and non-superconducting nanoparticles acting as good flux pinning centers. Previous studies have shown that hBN doping improves intrinsic critical current density (Jc) and Mg doping improves extrinsic Jc. In this study, the co-doping effect of 5 wt.% Mg and 1 wt.% hBN on bulk MgB2 samples fabricated using field assisted sintering is investigated. Furthermore, the influence of ball milling and processing temperatures on Mg-doped samples is also reported. The presence of Mg liquid during processing accelerates the reaction between BN and MgB2, forming an impurity phase, MgNB9, which adversely affects superconducting performance. However, a significant improvement in performance is achieved by increasing the sintering temperature in samples doped only with Mg.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Stephen J. Turrell, Hyeon Jeong Lee, Marco Siniscalchi, Sudarshan Narayanan, Mauro Pasta, Susannah C. Speller, Chris R. M. Grovenor
Summary: This study demonstrates the successful synthesis of a lithium-rich antiperovskite compound Li3OCl using RF magnetron sputtering. The stabilization of the antiperovskite phase and its distinction from Li2OHCl were confirmed through optimization of the synthesis and characterization processes.
MATERIALS ADVANCES
(2022)
Article
Materials Science, Multidisciplinary
Rebecca J. Nicholls, Sofia Diaz-Moreno, William Iliffe, Yatir Linden, Tayebeh Mousavi, Matteo Aramini, Mohsen Danaie, Chris R. M. Grovenor, Susannah C. Speller
Summary: This study reveals the effects of fast neutrons on high-temperature superconductors and the defects introduced by ion irradiation, which is important for the application of fusion reactors.
COMMUNICATIONS MATERIALS
(2022)
