Superconductivity最新文献

{"title":"Thickness dependence of the second magnetization peak effect in Ba0.6K0.4Fe2As2 single crystals","authors":"Yu-Hao Liu ,&nbsp;Wei Xie ,&nbsp;Hai-Hu Wen","doi":"10.1016/j.supcon.2024.100135","DOIUrl":"10.1016/j.supcon.2024.100135","url":null,"abstract":"<div><div>The second magnetization peak (SMP) effect has been observed widely in many type-II superconductors, but the reason remains elusive. This effect manifests an enhanced critical current density with magnetic field and should be very useful for applications. By measuring the magnetization of optimally doped Ba_0.6K_0.4Fe₂As₂ single crystals with different thickness, it is found the SMP effect exists in thick samples and gradually becomes invisible when the sample thickness is reduced to the scale of micrometer. Detailed investigation on the vortex dynamics on samples with different thickness clearly show that there is a common behavior of vortex dynamics in the low field region, which may be characterized by the Bragg glass like elastic vortex motion. This feature holds on in the whole field region for the thin samples, while it turns into the SMP effect for thicker samples when the field is increased. The results suggest that the SMP effect may be induced by the entanglement of the vortex system, and the absence of the SMP effect in thin samples is attributed to the cutoff of the entangled vortex length along c-axis.</div></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"12 ","pages":"Article 100135"},"PeriodicalIF":5.6,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142758928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and initial test results of a space-bound flux pump to energize the Hēki mission’s superconducting magnet","authors":"B.P.P. Mallett ,&nbsp;J. Clarke ,&nbsp;T. Endo ,&nbsp;M. Goddard-Winchester ,&nbsp;C. Shellard ,&nbsp;J. Olatunji ,&nbsp;R.A. Badcock ,&nbsp;R. Pollock","doi":"10.1016/j.supcon.2024.100129","DOIUrl":"10.1016/j.supcon.2024.100129","url":null,"abstract":"<div><div>Despite repeated proposals to utilize superconducting magnets in space since at least the 1970s, examples of their use remain scant. One of the technical challenges is to maintain suitable cryogenic temperatures on a spacecraft. This challenge can be alleviated by the use of flux pumps to reduce the required cryogenic cooling power needed to energize the superconducting magnet. This paper describes the design and initial test results of the flux pump to fulfill the requirements of the Hēki mission that will operate a high-temperature superconducting magnet on an external platform of the International Space Station. A transformer-based, self-rectifier architecture was chosen for the flux pump. An effective circuit model used to design its electromagnetic properties and finite-element modelling used in its mechanical and thermal design. Liquid nitrogen tests were used to demonstrate that the electrical performance of the flux pump meets requirements. Higher-fidelity tests using flight-like copies of the hardware and software were undertaken and validated the thermal modelling. These tests also featured the continuous operation of the flux pump in a conduction-cooled setting for over 100 h, reflecting an inherent reliability of this technology. Whilst further testing and flight qualification remains to be completed, we anticipate an on-orbit demonstration of this flux pump technology in April 2025. Such a demonstration will signal a maturing of this emerging superconducting technology for both in-space and terrestrial applications.</div></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"12 ","pages":"Article 100129"},"PeriodicalIF":5.6,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hēki: A superconducting magnet for space propulsion on the International space Station – Pathfinder design and experimental thermal testing","authors":"Jamal Olatunji ,&nbsp;Nicholas Strickland ,&nbsp;Max Goddard-Winchester ,&nbsp;Benjamin Mallett ,&nbsp;Celine Jane ,&nbsp;Cameron Shellard ,&nbsp;Emile Webster ,&nbsp;Betina Pavri ,&nbsp;Avinash Rao ,&nbsp;Randy Pollock","doi":"10.1016/j.supcon.2024.100133","DOIUrl":"10.1016/j.supcon.2024.100133","url":null,"abstract":"<div><div>Applied-field magnetoplasmadynamic (AF-MPD) thrusters are a high-power electric propulsion solution for satellites and spacecraft, offering high efficiency, high specific impulse and high thrust density.</div><div>The integration of high-temperature superconducting (HTS) electromagnets energised with flux pumps as the applied field module can significantly reduce the mass, power and volume of AF-MPD thrusters, making their deployment as practical spacecraft propulsion systems more feasible. To validate HTS magnet and flux pump technology, a New Zealand team led by the Paihau-Robinson Research Institute is collaborating with Nanoracks LLC to send an HTS magnet to the International Space Station (ISS). Dubbed the “Hēki Mission”, an HTS magnet and flux pump will be installed on the Nanoracks External Platform (NREP) for an in-space technology demonstration. This aims to gain space heritage for HTS magnets and flux pumps for the first time, a crucial step toward practical application and commercialisation of HTS-powered thrusters in space.</div><div>This paper details the preliminary design of the Hēki mission payload. An extension of work presented at the European Applied Superconductivity Conference in 2023, we provide more detail on the electromagnetic and thermal design of the “pathfinder” Hēki magnet, our first attempt at designing a realistic space payload that meets stringent size, weight and power requirements typical of a small satellite. Through the development of finite element models, we detail the electromagnetic design of the HTS magnet which features a large warm bore to accommodate future integration with a realistically sized AF-MPD thruster, and detail the design philosophy and mass optimisation tools developed to achieve a central field of 0.5 T while simultaneously magnetically shielding the magnet to comply with ISS safety requirements. We also detail the conduction cooled thermal design of the pathfinder Hēki magnet, showing how magnet temperatures below 75 K can be achieved with a cryogenic cooling system that consumes less than 100 W of electrical power. These thermal models were compared with thermal experiments in a simulated space environment for model validation purposes. Difficult to measure input variables such as the contact resistance between surfaces and the effective emissivity of the thermal radiation shielding were empirically determined to improve model predictive power.</div><div>Scheduled for launch in the first quarter of 2025, the Hēki pathfinder design outlined in this paper serves as a pivotal preliminary effort that has identified the major risks potentially impacting mission success. Consequently, this body of work represents a significant step forward in developing a flight-qualified system capable of achieving our space mission objectives.</div></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"12 ","pages":"Article 100133"},"PeriodicalIF":5.6,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143160457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quench behaviors of parallel-wound no-insulation high temperature superconductor coils","authors":"Yutong Fu ,&nbsp;Guangtong Ma ,&nbsp;Fangliang Dong ,&nbsp;Yawei Wang","doi":"10.1016/j.supcon.2024.100140","DOIUrl":"10.1016/j.supcon.2024.100140","url":null,"abstract":"<div><div>No-insulation (NI) high-temperature superconducting (HTS) coil wound with parallel-stacked tapes emerges as a prospective choice for high-field fusion magnets owing to lower inductance and faster ramping rate. The parallel stacked-tape structure leads to new current redistribution among stacked tapes in each turn during local quenches, which also considerably changes the current redistribution behavior through inter-turn contacts. Therefore, quench behaviors of parallel-wound no-insulation (PWNI) coil should differ from its counterpart wound with single tape, which are still unknown. This study is to illustrate quench behaviors of PWNI HTS coils induced by local hot spot. A multi-physics model integrating an equivalent circuit network, a FEM heat transfer module, and a FEM <strong><em>T-A</em></strong> model is developed to analyze the electromagnetic and thermal characteristics of PWNI HTS coils during quench. Results show that the transport currents are mainly redistributed among parallel-stacked tapes through terminal resistances when a local hot spot happens on one tape, while being less dependent on turn-to-turn electrical contacts. It leads to a coupling current within PWNI coils that is not present in NI coils wound with single tape (single-wound no-insulation (SWNI) coil), resulting in a highly non-uniform transport current distribution among parallel-wound tapes. The reduced terminal joint resistances further enhance the coupling current, potentially leading to an extra overcurrent quench risk in PWNI coils. Moreover, the current redistribution between parallel-stacked tapes inhibits the turn-to-turn current redistribution in the PWNI coil, thus significantly reducing its magnetic field degradation under a high heat disturbance, which can be almost less than half of the SWNI counterpart in this study. These results offer important theoretical guidance to safety operation and robustness improvement of high-field HTS magnets wound by PWNI technique.</div></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"12 ","pages":"Article 100140"},"PeriodicalIF":5.6,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143160461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of Sr/Ca on the phase evolution mechanism, phase purity and critical current density of Bi-2212 wires","authors":"Zhenbao Li,&nbsp;Guoqing Liu,&nbsp;Gaofeng Jiao,&nbsp;Xiaoyan Xu,&nbsp;Qingbin Hao,&nbsp;Kai Yao,&nbsp;Jianfeng Li","doi":"10.1016/j.supcon.2024.100136","DOIUrl":"10.1016/j.supcon.2024.100136","url":null,"abstract":"<div><div>Two batches of Bi-2212 precursor powder with Sr/Ca = 2.24, 2.33 were prepared by the spray pyrolysis technology. Then two Bi-2212 superconducting wires marked as Line4 and Line8-2 were prepared by the above powders. Line4 with Sr/Ca = 2.24 showed much higher phase purity, higher texture and its critical current density(<em>J_c</em>) was 1.5 times that of Line8-2 with Sr/Ca = 2.33. Their micro-structure evolution was scrutinized by quenching each wire at 7 instantaneous moments during the partial melting process(PMP). Bi-2212 was found to decompose into (Sr,Ca)₁₄Cu₂₄O_x(14:24AEC), Bi₉Sr₁₁Ca₅O_x(9:16CF), Bi-rich liquid Bi-2212 and Bi-rich solid Bi-2212 at the initial stage of PMP. When Bi-2212 began to solidify, the above four phases reacted to generate Bi-2212. By analyzing the particle size, the content and the composition variation for 14:24AEC, 9:16CF as well as the composition variation for Bi-2212 matrix in above 7 moments of PMP, the phase evolution’s difference between two wires was finally confirmed. The formation energy of 14:24AEC was smaller compared with 9:16CF, while 9:16CF was faster on dynamics. 14:24AEC determined the whole synthetic reaction’s rate of Bi-2212, and Sr/Ca as well as its value fluctuation in Bi-2212 precursor powder can decide both the timeline and the driving force of PMP. A larger Sr/Ca in Line8-2 made it melt earlier compared with Line4, which led to its earlier timeline during the melting stage of PMP. While the more consistent phase evolution’s pace between 14:24AEC and 9:16CF in Line4 finally contributed a larger Sr/Ca after solidification. Both the larger Sr/Ca and its larger fluctuation in Line4 finally contributed to its faster phase evolution’s pace, higher phase purity, better texture and higher <em>J_c</em>. The deep logic driving the phase evolution mechanism in Bi-2212 wires was disclosed for the first time, which will be very helpful to the future improvement of <em>J_c</em> for Bi-2212 wires.</div></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"12 ","pages":"Article 100136"},"PeriodicalIF":5.6,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143160458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of a novel joint-less double aperture REBCO magnet with an innovative excitation circuit for stable magnetic field generation","authors":"Hao Dong ,&nbsp;Daxing Huang ,&nbsp;Hao Yu ,&nbsp;Hongwei Gu ,&nbsp;Fazhu Ding","doi":"10.1016/j.supcon.2024.100139","DOIUrl":"10.1016/j.supcon.2024.100139","url":null,"abstract":"<div><div>Second-generation high-temperature superconducting (2G-HTS) magnets operating in persistent current mode (PCM) effectively address the challenge of magnetic field stability. This paper introduces a novel joint-less double aperture (JDA) REBa₂Cu₃O_7−δ (REBCO, RE: rare earth) magnet, designed to overcome the limitations posed by joint resistance in traditional 2G-HTS magnets. A single slit REBCO tape is innovatively wound into double-pancake (DP) coils on both sides and placed in spaced apertures within the magnet. This closed-loop design generates two stable magnetic fields while effectively preventing tape twisting between the DP coils. Furthermore, a new portable excitation circuit is proposed for the JDA REBCO magnet, utilizing pulsed magnetic fields generated by the copper coil, which eliminates the need for current leads, electrodes, and persistent current switches (PCSs), significantly reducing system complexity. Initially, a traditional PCS was used to charge the JDA REBCO magnet to 40 A at 77 K, generating a magnetic field of 60.6 mT at the center of one of the DP coil apertures. The magnet was then successfully excited using a pulse circuit after about 200 cycles. A comparative analysis with the PCS results showed that the current induced by the pulse circuit was approximately 40 A. The stability of the magnetic field within one DP coil of the JDA REBCO magnet was monitored for 107 h, with a magnetic field drift rate of approximately 0.86 ppm/h. The closed-loop advantage of the JDA REBCO magnet, combined with the portable pulsed excitation circuit, demonstrates the promising potential for applications in double aperture magnetic resonance imaging (MRI) equipment, particle accelerators, and other advanced technologies.</div></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"12 ","pages":"Article 100139"},"PeriodicalIF":5.6,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143160460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Topological versus conventional superconductivity in a Weyl semimetal: A microscopic approach","authors":"Enrique Muñoz ,&nbsp;Juan Esparza ,&nbsp;José Braun ,&nbsp;Rodrigo Soto-Garrido","doi":"10.1016/j.supcon.2024.100132","DOIUrl":"10.1016/j.supcon.2024.100132","url":null,"abstract":"<div><div>Starting from a microscopic model for the particle–particle interactions in a Weyl semimetal, we analyzed the possibility for conventional as well as monopole Cooper pairing between quasiparticle excitations at the same (intra-nodal) or opposite (inter-nodal) Weyl nodes. We derived a coupled system of self-consistent BCS-like equations, where the angular dependence of the pairings is directly determined from the microscopic interaction symmetries. We studied the competition between conventional and monopole superconducting phases, thus obtaining explicitly the phase diagrams from the microscopic interaction model parameters. We determined the critical temperatures for both phases, and the low temperature critical behavior, including the specific heat, that we suggest as possible experimental probe for topological quantum criticality in Weyl semimetals.</div></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"12 ","pages":"Article 100132"},"PeriodicalIF":5.6,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143160456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recent progress in high-temperature superconducting undulators","authors":"Zhuangwei Chen ,&nbsp;Marco Calvi ,&nbsp;John Durrell ,&nbsp;Cristian Boffo ,&nbsp;Dabin Wei ,&nbsp;Kai Zhang ,&nbsp;Zhentang Zhao","doi":"10.1016/j.supcon.2024.100134","DOIUrl":"10.1016/j.supcon.2024.100134","url":null,"abstract":"<div><div>Considerable effort has been devoted to the development of superconducting undulators (SCUs) intended for particle accelerator-based light sources, including synchrotrons and free electron laser (FEL) facilities. Recently, a high-temperature superconducting (HTS) undulator prototype, consisting of staggered-array Re-Ba-Cu–O bulks, achieved an on-axis sinusoidal magnetic field profile with a peak amplitude <em>B</em>₀ of 2.1 T and a period length of 10 mm, resulting in a deflection parameter <em>K</em> = 1.96. Such a short period HTS undulator not only enables the generation of higher-energy photons, but also supports the construction of economically feasible and compact FELs with shorter linear accelerators (LINACs). This article provides a comprehensive review of recent advances in the staggered-array bulk HTS undulator as well as other types of HTS undulators. Furthermore, it offers insights into the development of engineering HTS undulator prototypes designed for deployment in synchrotron and free electron laser (FEL) facilities. We conclude by discussing opportunities for and the challenges facing the use of HTS undulators in practical applications.</div></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"12 ","pages":"Article 100134"},"PeriodicalIF":5.6,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142758927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Meter-length REBCO ultralow resistance joint for the gigahertz NMR magnet","authors":"Xiaoru Tian ,&nbsp;Hongli Suo ,&nbsp;Zili Zhang ,&nbsp;Maolai Ye ,&nbsp;Lei Wang ,&nbsp;Jianhua Liu ,&nbsp;Qiuliang Wang","doi":"10.1016/j.supcon.2024.100138","DOIUrl":"10.1016/j.supcon.2024.100138","url":null,"abstract":"<div><div>In this paper, we present a meter-length REBCO joint using the most conventional soldering method. The joint resistance can attain 7.21 × 10^-11 Ω at 4.2 K with a joint length of 2 m. It essentially displays a linear relationship with the joint length. The microstructures of the joints were investigated systematically using scanning electron microscopy (SEM) and micro-computed tomography (micro-CT). Multiple voids were identified in all the joints. More importantly, the voids were not distributed homogeneously. The internal voids near the innermost and outermost rings were larger than those in the middle ring. Two types of gigahertz magnetic resonance spectroscopy (NMR) magnets were designed: 15 T low temperature superconductor (LTS) + 15 high temperature superconductor (HTS) and whole HTS. The current 10^-11 Ω-level joint can satisfy the magnetic field decay criterion of 1 ×10^-8/h. However, a pure HTS gigahertz NMR magnet requires a joint length of over 20 m, which is not feasible. The current resistance resource of the meter-length joint was also discussed by an equivalent circuit analysis. This paper presents a reliable engineering REBCO joint fabrication method for gigahertz NMR magnets without heat treatment.</div></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"12 ","pages":"Article 100138"},"PeriodicalIF":5.6,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143160459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Chinese magneto-biased superconducting current limiter has achieved long-term grid-connected demonstration, withstanding transmission line fault","authors":"Jiahui Zhu ,&nbsp;Zhengyu Li ,&nbsp;Jianfeng Sun ,&nbsp;Defu Wei ,&nbsp;Kaizhong Ding","doi":"10.1016/j.supcon.2024.100131","DOIUrl":"10.1016/j.supcon.2024.100131","url":null,"abstract":"","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"12 ","pages":"Article 100131"},"PeriodicalIF":5.6,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142707271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}