Article
Physics, Applied
Y. Yanagisawa, R. Piao, Y. Suetomi, T. Yamazaki, K. Yamagishi, T. Ueno, T. Takao, K. Ohki, T. Yamaguchi, T. Nagaishi, H. Kitaguchi, Y. Miyoshi, M. Yoshikawa, M. Hamada, K. Saito, K. Hachitani, Y. Ishii, H. Maeda
Summary: This paper describes the first persistent-mode medium magnetic field nuclear magnetic resonance (NMR) magnet using superconducting joints between high-temperature superconductors (HTS), aiming to develop a high-resolution NMR magnet. By developing superconducting joints between HTSs and HTSs/LTSs, the authors have successfully demonstrated a magnet that functions properly in a high-resolution NMR system.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2021)
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)
Review
Metallurgy & Metallurgical Engineering
Hao Liang, Dipak Patel, Mahboobeh Shahbazi, Andrzej Morawski, Daniel Gajda, Matt Rindfleisch, Richard Taylor, Yusuke Yamauchi, Md Shahriar A. Hossain
Summary: Magnesium diboride (MgB2) magnets have the potential to be the next-generation liquid-helium-free magnet for magnetic resonance imaging (MRI) application. This literature review summarizes research and development on MgB2 superconducting joining technology.
JOURNAL OF MAGNESIUM AND ALLOYS
(2023)
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
Computer Science, Information Systems
Li Lu, Wei Wu, Xin Yu, Zhijian Jin
Summary: The null-flux electro-dynamic suspension (EDS) system is a feasible high-speed maglev system utilizing superconducting magnets. The study focuses on the development of HTS non-insulation closed-loop coils module for EDS system which exhibits premier thermal quenching self-protection. The full-size double-pancake (DP) module designed in the study was tested in a liquid nitrogen environment, showing an average decay rate of 0.58% per day in the persistent current mode.
Article
Crystallography
Yajun Xia, Yuntao Song, Huajun Liu, Zhen Lu, Jinxing Zheng, Fang Liu, Meng Song
Summary: High temperature superconducting magnets are at risk of quench, which can be dangerous. A quench protection system using dump resistances and copper discs is proposed to reduce current and release energy. The effect of different copper discs on the discharging process of HTS coils is discussed, and it is found that copper discs with higher residual resistivity ratios perform better in quench protection.
Article
Engineering, Electrical & Electronic
V. Marinozzi, P. Ferracin, G. Vallone
Summary: High energy physics research requires more powerful circular accelerators in the future. To achieve this, dipole magnets capable of producing a large magnetic field are desired. A 20 T dipole magnet is considered ideal for constructing an 80 km machine that can circulate 100 TeV proton beams. However, current technology limits the use of Low-Temperature Superconductors (LTS) to around 16 T for accelerator magnet applications. This paper presents the design of a 6-layer 20 T hybrid dipole magnet using Nb3Sn (LTS) and Bi2212 (HTS), demonstrating the possibility of achieving the desired magnetic field with sufficient margin on a realistic conductor.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2023)
Article
Physics, Applied
Bradley Leuw, Jianzhao Geng, James H. P. Rice, Dominic A. Moseley, Rodney A. Badcock
Summary: A new type of high temperature superconducting (HTS) flux pump has been designed and verified, which utilizes Jc(B) switching to achieve transformer-rectification of the magnetic flux. This technology offers higher electrical power efficiency and overthrows the limitation that traditional HTS flux pumps can only maintain magnetic fields rather than rapidly apply them.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2022)
Article
Energy & Fuels
Xueliang Wang, Jie Sheng, Xiao-Fen Li, Jiamin Zhu, Longbiao Wang, Zhuyong Li, Zhijian Jin
Summary: This article introduces a Field-based cable to improve the utilization rate of superconducting magnets. The feasibility of this method is validated by designing and fabricating a typical no-insulation coil. The design of the cable is based on the magnetic field distribution, potentially reducing the cost of HTS materials.
JOURNAL OF ENERGY STORAGE
(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)
Article
Physics, Applied
Pengbo Zhou, Asef Ghabeli, Mark Ainslie, Francesco Grilli
Summary: Flux pumps provide a solution for contactless charging of HTS coils, and understanding the dynamics of the charging process is essential. This study proposes a methodology for coupling HTS coil and flux pump models using an electrical circuit. Validation of the approach shows good agreement with experimental results, and it is suggested to leave a margin between the operating current and the coil's critical current when using flux pumps.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(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
Chemistry, Physical
Vincenzo D'Auria, Pierluigi Bruzzone, Mickael Sebastian Meyer, Enrique Rodriguez Castro, Stefano Sgobba
Summary: This paper reports on the application of copper thermal spraying in the manufacturing process of an electrical connection between Nb3Sn cables for superconducting magnets of fusion reactors. It is shown that the prototype has a resistance of 0.48 n omega, despite a 40% oxide concentration in the copper coating, and the contact ratio between the jointed surfaces is about 95%.
Article
Physics, Applied
Wanshuo Sun, Lei Wang, Shunzhong Chen, Junsheng Cheng, Qiuliang Wang
Summary: Nb3Sn superconducting joints were developed through powder metallurgy and their characteristics were investigated. The crystal morphology, phase distribution, grain boundaries, and physical grain orientation of the joints were analyzed using electron backscatter diffraction. The Nb3Sn-Nb3Sn joints exhibited electrical resistances at the 10(-13) ohm level under a 5.5 T magnetic field, as measured by current decay method.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2023)
Article
Physics, Applied
Magnus Dam, William Jerome Burger, Rita Carpentiero, Enrico Chesta, Roberto Iuppa, Glyn Kirby, Gijs de Rijk, Lucio Rossi
Summary: The ARCOS magnet is a toroidal magnet with 12 coils that is proposed for use in a next-generation magnetic spectrometer in space. AMaSED-2 is a smaller-scale prototype coil for the ARCOS magnet, consisting of two individually built high-temperature superconducting coils. The coil was manufactured and tested at CERN, achieving central magnetic flux densities up to 2.9 T. The design and characterization of AMaSED-2 are crucial for the future development of a flight model.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2023)
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
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
Physics, Applied
Hakan Yetis, Dogan Avci, Firat Karaboga, Canan Aksoy, Daniel Gajda, Elena Martinez, Fatih Mehmet Tanyildizi, Andrzej Zaleski, Michal Babij, Lan Maria Tran, Luis Alberto Angurel, G. F. de la Fuente, Ibrahim Belenli
Summary: We report the transport, electromechanical, and structural properties of single core MgB2/Fe wire produced using a new fabrication method called designed internal Mg diffusion (IMD) process. This method involves the use of non-stoichiometric Mg + B pellets instead of a central Mg rod in the standard IMD method. The results show that the designed IMD method significantly increases the engineering critical current density (J(e)), and the central porous MgB2 structure acts as an internal stabilizer against quench damage at high applied currents.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2022)
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
Dogan Avci, Hakan Yetis, Daniel Gajda, Michal Babij, Lan Maria Tran, Firat Karaboga, Canan Aksoy, Andrzej Zaleski, Ibrahim Belenli
Summary: A new type of superconducting joining technique was developed for joining unreacted internal Mg diffusion (IMD) single-core MgB2 wires. The technique involved fabricating a small diameter joint mould using a Nb/Cu composite tube and a longitudinal semi-cylindrical Mg and B core. The joint exhibited excellent contact with the superconducting MgB2 bulk material and had low resistance and rapid cooling properties.
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)
