Superconductivity最新文献

{"title":"Effect of Gd addition on the superconducting properties of Ti-based V, Nb, Ta alloys","authors":"SK Ramjan ,&nbsp;L.S. Sharath Chandra ,&nbsp;Rashmi Singh ,&nbsp;M.K. Chattopadhyay","doi":"10.1016/j.supcon.2023.100048","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100048","url":null,"abstract":"<div><p>The critical current density (<span><math><mrow><msub><mrow><mi>J</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span>) of the body centered cubic (<em>bcc</em>) V_0.6Ti_0.4 alloy enhances significantly after the addition of rare earth Gd as the latter is immiscible in the matrix [S. Paul, et.al, IEEE Trans. Appl. Supercond. <strong>31</strong>, 5 (2021)]. Very low solubility of Gd in other <em>bcc</em> elements like Ta and Nb is also well known [Jr. KA Gschneidner in Prog Sci Technol Rare Earths, vol. 1, pp. 222–258, 1964 <span><math><mrow><mi>&amp;</mi></mrow></math></span> M Neuberger, et.al in Handbook of Electronic Materials, Vol 4, 1972]. We use these facts to find the effect of adding 1 at.% Gd into the Nb_0.6Ti_0.4 and Ta_0.4Ti_0.6 alloys on the superconducting properties e.g., the transition temperature (<span><math><mrow><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span>), <span><math><mrow><msub><mrow><mi>J</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span>, flux pinning force density (<span><math><mrow><msub><mrow><mi>F</mi></mrow><mrow><mi>p</mi></mrow></msub></mrow></math></span>) and the microstructure. In spite of Gd being ferromagnetic, the <span><math><mrow><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span> in these alloys change only marginally (increase by 0.3 K in Ta_0.4Ti_0.6 and decrease by 0.15 K in Nb_0.6Ti_0.4 after Gd addition. The <span><math><mrow><msub><mrow><mi>J</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span> (<span><math><mrow><mi>H</mi><mo>=</mo><mn>1</mn></mrow></math></span> T, <em>T</em> = 4 K) increases by 5 and 1.5 times respectively in the Gd containing Nb_0.6Ti_0.4 and Ta_0.4Ti_0.6 alloys, which is quite small as compared to the increase observed in the V_0.6Ti_0.4 (20 times) system. With Gd addition, the grain size reduces approximately by 65% and 10% respectively in Nb_0.6Ti_0.4 and Ta_0.4Ti_0.6. Our analysis indicates that grain boundaries are the major flux line pinning centres in these alloys and the role of Gd in increasing the <span><math><mrow><msub><mrow><mi>J</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span> depends on the effectiveness of Gd in reducing the grain size. The grain boundary density depends strongly on the distribution of Gd precipitates, which is quite different from each other for two alloy systems under study. Moreover, our results suggest that the addition of Gd to commercial Nb-Ti (Nb_0.37Ti_0.63) alloy is a new promising route for achieving higher <span><math><mrow><msub><mrow><mi>J</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span> values.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"6 ","pages":"Article 100048"},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49880874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Low-temperature superconductors: Nb3Sn, Nb3Al, and NbTi","authors":"Nobuya Banno","doi":"10.1016/j.supcon.2023.100047","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100047","url":null,"abstract":"<div><p>Low-temperature superconducting (LTS) wires are of significant importance in high-field magnet applications. Current developments of the LTS wires are attributed to many studies. Particularly, Nb₃Sn is an attractive superconductor with substantial potential for performance improvement in view of an ideal microstructure that maximizes flux pinning properties. To date, various reviews have been reported on the physical properties of low-temperature superconductors. Therefore, this review focuses on understanding the fundamental phase formations and microstructural controls of low-temperature superconductors from the perspectives of growth kinetics, nucleation theory, and chemical potentials to facilitate the syntheses of these superconductors and advancement of wire production. Taking Nb₃Sn as an example, the effect of Cu addition to Nb₃Sn on Nb/Sn reactive diffusion is briefly described. Then, representative Nb₃Sn formations are schematically summarized to broaden our understanding of the development behaviors of Nb₃Sn. These behaviors are qualitatively reviewed in terms of Sn chemical potential. After mentioning the potential for performance improvement of Nb₃Sn, the influences of element additions, specifically those of Zr and Hf additions, resulting in breakthrough microstructural refinements, on Nb/Sn diffusion are investigated. Subsequently, strengthening of the matrix via element additions is reviewed. Thereafter, taking Nb₃Al as an example, the features of Nb₃Al formation and basic development processes, including low-temperature processes, metastable phase transformations, and microstructural control, are described. Strain sensitivity, one of the most important properties of Nb₃Al, is also briefly reviewed. Then, taking Nb alloy as an example, <em>α</em>-Ti precipitation in a binary Nb–Ti system is concisely summarized. Subsequently, recently reported new artificial pin incorporation based on a powder method is introduced, followed by a unique study of the application of high-temperature-tolerable Nb superconducting alloys in superconducting joints. This review makes a novel contribution to the literature as it provides a comprehensive understanding of phase formation in low-temperature superconductors.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"6 ","pages":"Article 100047"},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49880875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design of a finite impulse response filter for rapid single-flux-quantum signal processors based on stochastic computing","authors":"Ruidi Qiu,&nbsp;Peiyao Qu,&nbsp;Xiangyu Zheng,&nbsp;Guangming Tang","doi":"10.1016/j.supcon.2023.100045","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100045","url":null,"abstract":"<div><p>Rapid-Single-Flux-Quantum (RSFQ) circuit technology is well known for its low power consumption and latency, which enables digital signal processing up to tens of GHz. As a fundamental digital filter, the Finite Impulse Response (FIR) filter has wide applications in communication systems. A design of an FIR filter based on RSFQ circuit technology is proposed. However, the FIR filter consumes large amounts of adders and multipliers. Based on Stochastic Computing (SC) theory with which adder and multiplier are much simpler, the hardware cost of FIR filter is dramatically reduced. A novel stochastic number generator (SNG), a stochastic-to-binary converter (SBC), and the FIR filter were designed and verified via logic simulation with a target frequency of 10 GHz. The results indicated the FIR filter performs correct operations. The proposed FIR filter consists of 2255 Josephson junctions (JJs) without wiring cells (i.e., Josephson Transmission Lines (JTLs), Passive Transmission Lines (PTLs)), which is acceptable, making it possible to be used in RSFQ digital signal processors.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"6 ","pages":"Article 100045"},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49880862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"AC loss mitigation for high temperature superconducting coils in wireless power transfer","authors":"Hongyi Chen ,&nbsp;Hongye Zhang","doi":"10.1016/j.supcon.2023.100044","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100044","url":null,"abstract":"<div><p>With the rapid development of high temperature superconducting (HTS) technology, second generation (2G) HTS materials have become a promising alternative to traditional conductive materials in the power transmission industry. Recently, the topic of using HTS materials in wireless power transfer (WPT) systems for electric vehicles (EVs) has attracted widespread attention in the background of net zero transport. With virtually zero DC resistance and superior current-carrying capacity, HTS materials can achieve high quality factor and power density in the WPT resonant circuits compared to conventional metals, e.g., copper. However, the optimal working frequency for the conventional WPT system is relatively high in the order of kilohertz level. Superconducting coils working at high frequencies could generate high AC losses, reducing the overall power transfer efficiency (PTE) and increasing the cooling burden. In order to improve the PTE of HTS-WPT systems, the AC loss mitigation methods for different HTS coil topologies have been investigated in this paper by varying the inter-turn gap and tape width. Three HTS coil structures, namely the spiral coil, the solenoid coil and the double pancake (DP) coil, have been studied with a 2D axisymmetric multi-layer numerical model based on the <strong><em>H</em></strong> - formulation, and the simulation results have been validated by the published experimental data. The general loss characteristics, loss distributions in each turn, as well as magnetic flux densities have been analysed in detail for three types of HTS coils. Moreover, the impact of these two loss reduction methods on the WPT performance has also been evaluated. Findings have shown that increasing the inter-turn gap and tape width can effectively reduce the AC power losses and increase the PTE of the HTS-WPT system. The spiral coil demonstrates the highest AC power loss reduction effect and PTE while maintaining a stable level of magnetic fields. This paper is believed to deepen the understanding of superconducting WPT and provide a useful reference for more efficient wireless energisation applications.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"6 ","pages":"Article 100044"},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49880861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hope and challenge of ternary hydrogen-based superconductors under pressure","authors":"Guangtao Liu,&nbsp;Hanyu Liu","doi":"10.1016/j.supcon.2023.100046","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100046","url":null,"abstract":"","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"6 ","pages":"Article 100046"},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49880858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"J-A formulation: A finite element methodology for simulating superconducting devices","authors":"Gabriel dos Santos ,&nbsp;Bárbara Maria Oliveira Santos ,&nbsp;Felipe Sass ,&nbsp;Flávio Goulart dos Reis Martins ,&nbsp;Guilherme Gonçalves Sotelo ,&nbsp;Rubens de Andrade Junior","doi":"10.1016/j.supcon.2023.100049","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100049","url":null,"abstract":"<div><p>High-temperature superconductors are a powerful technological option to be applied in the current scenario of energy transition. Their applications include fault current limiters, power electrical cables, and electrical machines, for example. Due to the non-linearities of superconductors, it is computationally costly to run real models of superconducting equipment. Therefore, it is of paramount importance to have a reliable and fast formulation to model superconducting devices. This paper proposes a new hybrid J-A formulation to simulate superconducting devices. The new formulation is validated with 5 case studies, some of which are benchmarks. The J-A formulation agrees in all cases and has a smaller computation time when compared with the T-A formulation. Moreover, due to the simple implementation, the proposed formulation allows the possibility of running the J and A formulations in the same order and presents itself as a potential feature to speed up and help the design of the superconducting devices.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"6 ","pages":"Article 100049"},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49880860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Concept design of an HTS linear power generator for wave energy conversion","authors":"Petrus Kambo ,&nbsp;Yuhi Yamanouchi ,&nbsp;Antomne A. Caunes ,&nbsp;Kota Yamaguchi ,&nbsp;Mitsuru Izumi ,&nbsp;Tetsuya Ida","doi":"10.1016/j.supcon.2023.100043","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100043","url":null,"abstract":"<div><p>We show a conceptual structure for a wave energy converter, which features a direct-drive linear power generator with REBaCuO high-temperature superconducting (HTS) bulk field poles and driven by a heaving buoy. A dual translator power generation system of the proposed concept structure is a linear generator in which both the HTS bulks and armature copper coils move in opposite directions simultaneously. A performance analysis of our linear generator was conducted using a finite-element electromagnetic field analysis method. The results of the analysis were compared between the HTS dual translator linear power generator and the HTS single translator linear power generator. The maximum electromagnetic force and the average output power of the HTS dual translator are around 5 % and 11 % higher than that of the HTS single translator. We further present the results of the analysis regarding the influence of reducing the stroke length of the linear generator translator on the output power, where the output power for the HTS dual translator system increased up to a factor of two, in comparison to the HTS single translator counterpart, for the same reduction of stroke length.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"6 ","pages":"Article 100043"},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49880859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Electromagnetic analysis and AC losses of triaxial cables with multiple 2G-HTS layers per phase","authors":"M. Clegg,&nbsp;H.S. Ruiz","doi":"10.1016/j.supcon.2023.100039","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100039","url":null,"abstract":"<div><p>For an accurate estimation of the AC losses of superconducting triaxial cables, in this paper we present a two-dimensional model capable to provide a global assessment of multi-layer triaxial cables, validated against the reported AC-losses measurements on single-phase cables provided by the Russian Scientific and Research Institute of the Cable Industry (VNIIKP). Four models are presented, the first being a single-phase cable of 50 tapes and the others being three triaxial cables made of up to 135 coated conductors distributed in up to 9 layers. A systematic study is devised, where the number of layers per phase increases from 1 to 3, with at least 14 tapes distributed across each layer of the first (innermost) phase, 15 in the secondary (middle) phase, and 16 in the third (outermost) phase, respectively. Remarkably, our results reveal that the simple strategy of considering an unbalanced distribution for the amplitudes of the applied current, can generally balance the magnetic field between the three phases even for the bilayer and trilayer cables, resulting in negligible magnetic leaks in all situations. Besides, our high-resolution simulations allow to see for the first time how the transport and magnetization currents distribute across the thickness of all the superconducting tapes, from which we have found that the AC-losses of the 2nd phase is generally higher than at the other phases at low to moderate transport currents, <span><math><mrow><msub><mrow><mi>I</mi></mrow><mrow><mi>tr</mi></mrow></msub><mo>&lt;</mo><mn>0.8</mn><msub><mrow><mi>I</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span>, being <span><math><mrow><msub><mrow><mi>I</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span> the critical current of the corresponding tapes. Nevertheless, depending on whether the <span><math><mrow><msub><mrow><mi>I</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span> of the SC tapes at the 3rd phase layers is lower than the one at the 2nd phase, the layers at the third phase can exhibit a considerable increment on the AC losses. This is result of the considered magneto angular anisotropy of the superconducting tapes, which lead to intriguing electromagnetic features that suggest a practical threshold for the applied transport current, being it <span><math><mrow><mn>0.8</mn><msub><mrow><mi>I</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span>. Likewise, the relative change in the AC-losses per adding layers, per phase, and as a function of the entire range of applied transport current is disclosed.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"5 ","pages":"Article 100039"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49884128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Erratum to “Preparation of Bi-2212/YBCO heterostructure and their interfacial characters” [Superconductivity 4 (2022) 100030]","authors":"Minghu Shen ,&nbsp;Li Lei ,&nbsp;Gaoyang Zhao ,&nbsp;Pengrong Ren ,&nbsp;Mengmeng Ren ,&nbsp;Man Wu ,&nbsp;Bo Deng","doi":"10.1016/j.supcon.2022.100035","DOIUrl":"https://doi.org/10.1016/j.supcon.2022.100035","url":null,"abstract":"","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"5 ","pages":"Article 100035"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49884123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phase evolution mechanism study and fabrication of PbMo6S8 superconducting materials with two-step sintering process","authors":"Botao Shao ,&nbsp;Lingfeng Ling ,&nbsp;Shengnan Zhang ,&nbsp;Jixing Liu ,&nbsp;Lei Zhi ,&nbsp;Jianqing Feng ,&nbsp;Chengshan Li ,&nbsp;Jianfeng Li ,&nbsp;Pingxiang Zhang","doi":"10.1016/j.supcon.2023.100038","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100038","url":null,"abstract":"<div><p>PbMo₆S₈ superconducting materials are considered to have great potential for practical applications at low temperatures and high fields due to their high upper critical field, low anisotropy, and low preparation cost. In this work, PbMo₆S₈ bulks were prepared through a solid-state sintering process using PbS, Mo, and MoS₂ as raw materials. The phase evolution mechanism during the sintering of PbMo₆S₈ was studied in detail. It was found that during sintering at 750 °C for 24 h, both the S and Pb atoms diffuse into the Mo and MoS₂ particles, leading to the formation of the PbMo₆S₈ phase. After sintering at 950 °C for 72 h, a high superconducting phase content was obtained in the bulk; however, numerous pores remained. Therefore, in order to obtain a higher density for the bulk, a two-step sintering process was developed. Based on this technique, PbMo₆S₈ bulks with a higher bulk density and a higher superconducting phase content were obtained. This study provides an effective method for the fabrication of high-quality precursor powders, which can be the foundation for the future fabrication of PbMo₆S₈ superconducting long wires or tapes for practical applications.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"5 ","pages":"Article 100038"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49884127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}