Physica C-superconductivity and Its Applications最新文献

{"title":"Optimization of the Halbach permanent magnet guideway in HTS maglev based on sensitivity analysis","authors":"Tianyu Xing ,&nbsp;Jinkai Zhang ,&nbsp;Yan Li ,&nbsp;Can Peng ,&nbsp;Peiyu Yin ,&nbsp;Zigang Deng","doi":"10.1016/j.physc.2025.1354761","DOIUrl":"10.1016/j.physc.2025.1354761","url":null,"abstract":"<div><div>As an important part of the high-temperature superconducting (HTS) maglev system, the performance and stability of the permanent magnet guideway (PMG) is directly related to the loading capacity and safe operation of the HTS maglev train. Therefore, it is necessary to carry out optimization research on the performance of PMG. At present, PMG optimization studies are mostly from the perspective of magnetic circuit, and seldom considered from the perspective of statistical analysis. In this paper, a PMG optimization method based on sensitivity analysis is discussed. First, the PMG dataset is established by simulation with parametric sweeping method. Then, the influence of permanent magnet (PM) dimension and grade on the electromagnetic force of HTS maglev system is investigated using sensitivity analysis method. And the optimization suggestions for the HTS maglev system are given. Finally, the optimization method is applied to present a PMG optimization case, and the optimization results show that the maximum vertical magnetic field is increased by 16.57 %, the maximum lateral magnetic field is increased by 10.97 %, the levitation force of the HTS bulks is increased by 3.23 %, and the guidance force is increased by 11.78 %.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"635 ","pages":"Article 1354761"},"PeriodicalIF":1.3,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144588738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The inhomogeneous flow behavior of in iron-based superconducting tape production: Formation mechanism and impact on transport performance","authors":"Meng Han ,&nbsp;Chao Yao ,&nbsp;Dongliang Wang ,&nbsp;He Huang ,&nbsp;Chiheng Dong ,&nbsp;Xianping Zhang ,&nbsp;Yanwei Ma","doi":"10.1016/j.physc.2025.1354764","DOIUrl":"10.1016/j.physc.2025.1354764","url":null,"abstract":"<div><div>Iron-based superconductors (IBSs) have emerged as promising candidates for high-field applications, with various IBS wires and tapes developed through advanced fabrication techniques. However, the inhomogeneity of superconducting cores in practical conductors remains a persistent challenge, prevalent in nearly all types of powder-in-tube (PIT) superconducting tapes and significantly degrading both transport performance and mechanical properties. Here, we investigate the deformation behavior of Ba_xK_1-xFe₂As₂ (BaK122) tapes and elucidate the formation mechanism of non-uniform superconducting cores. By simulating the actual rolling process of Ag-sheathed BaK122 (BaK122/Ag) tapes, we reveal the in-situ flow behavior of the BaK122 core within the tape. The inhomogeneity of the BaK122 core arises from the plastic flow mismatch with the outer sheath during rolling, attributed to the core's lower plasticity compared to the metal sheath. The periodic characteristics of this inhomogeneous distribution are precisely identified. Furthermore, we demonstrate that rolling speed is a critical factor, with reduced rolling velocity alleviating strain rate mismatch. However, excessively low rolling speeds compromise core densification by enhancing horizontal transverse expansion. An optimal rolling velocity exists to balance uniformity and densification of the BaK122 core. Using the BaK122/Ag tape as a model system, we determine and experimentally validate this optimal rolling velocity through a series of studies, particularly via superconducting transport current measurements. Our findings provide essential guidance for achieving uniform fabrication of heterogeneous composites, such as high-temperature superconducting tapes.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"635 ","pages":"Article 1354764"},"PeriodicalIF":1.3,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144588740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design of superconducting magnets for high energy beam transport lines for proton cancer therapy","authors":"Gang He ,&nbsp;Yi Zhu ,&nbsp;Wenjie Yang ,&nbsp;Yu Liang ,&nbsp;Yiqin Lei ,&nbsp;Yanbing Yang ,&nbsp;Pengshan Chang ,&nbsp;Lizhen Ma ,&nbsp;Guangquan Chen ,&nbsp;Kedong Wang ,&nbsp;Xu Zhang ,&nbsp;Kai Wang ,&nbsp;Tianfa Liao","doi":"10.1016/j.physc.2025.1354718","DOIUrl":"10.1016/j.physc.2025.1354718","url":null,"abstract":"<div><div>In proton cancer therapy, to overcome the size and performance limitations of conventional electromagnetic systems, we have designed a superconducting high-energy beam transport line that utilizes superconducting magnets to provide higher magnetic fields, thereby significantly reducing system size and enhancing efficiency. The transport line consists of six groups of superconducting magnets, each employing a discrete cosine theta (DCT) coil structure <span><span>[1]</span></span>, <span><span>[2]</span></span>, <span><span>[3]</span></span>, <span><span>[4]</span></span>, <span><span>[5]</span></span>, comprising one curved dipole magnet and two quadrupole magnets, forming a Q-D-Q (quadrupole-dipole-quadrupole) configuration. The dipole magnet generates a central field of 2.77 T with a bending radius of 900 mm, while the quadrupole magnets have a gradient of 40 T/m. To ensure magnetic field quality, we developed a parametric model in CST and optimized the field characteristics, achieving an integral magnetic field uniformity of better than 0.01%. During rapid excitation, eddy current losses in metallic structures and AC losses in superconductors lead to temperature rise, which may trigger quenching. To mitigate this, we developed a detailed finite element model (FEM) in ANSYS and optimized the magnet’s cooling structure, ensuring that the maximum temperature rise is limited to 0.66 K over three operating cycles. Simultaneously, we established a 2D structural model to analyze the stresses in the magnet, confirming that the Von Mises stress is lower than the yield stress. Through these optimizations, a prototype was successfully fabricated to explore the manufacturing process of the Q-D-Q magnets. This work not only provides a technical foundation for future mass production but also offers critical technical reserves for the construction of superconducting Gantries.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"635 ","pages":"Article 1354718"},"PeriodicalIF":1.3,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144588735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Pt-Ti thin-film heating method for de-fluxing SFQ circuits in superconducting computers","authors":"Zhichao Chen,&nbsp;Jian Zhou,&nbsp;Lingyun Li,&nbsp;Lixing You","doi":"10.1016/j.physc.2025.1354748","DOIUrl":"10.1016/j.physc.2025.1354748","url":null,"abstract":"<div><div>This paper proposes a Platinum (Pt)-Ti (Titanium) thin-film heating method for de-fluxing Single Flux Quantum (SFQ) circuits, addressing key limitations of conventional hotspot-based approaches, such as non-uniform temperature distribution, low thermal efficiency, and delayed response. A comprehensive analysis and performance evaluation of different heating methods are conducted to investigate the impact of heat methods on Josephson junction (JJ) de-fluxing. Superconducting computers, which use SFQ logic for high-speed operation and ultra-low power consumption, suffer from logical errors caused by trapped magnetic flux in JJs. To de-flux an SFQ circuit after logic errors, the JJs must be heated above the threshold temperature and then cooled in the absence of a magnetic field. Our studies show that heating the JJs to 22 K or above reliably removes trapped flux. Pt thin-film resistive materials, known for their rapid thermal response and controllable diffusion, offer a more efficient solution for de-fluxing and thermal control in SFQ circuits. The thin-film method demonstrates superior performance, achieving a more uniform temperature distribution (standard deviation of 0.02 K), faster thermal response within 1.2 s, and an optimal heating power of 1500 mW with an effective heating duration of 2 s. These results demonstrate a reliable and efficient de-fluxing method, essential for restoring functionality and ensuring logical error recovery in large-scale superconducting computers.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"635 ","pages":"Article 1354748"},"PeriodicalIF":1.3,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144588737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Something about the Mechanism of Induction Phenomena: The forgotten work of Berta de Haas-Lorentz on diamagnetism in superconductors","authors":"Giulia Venditti ,&nbsp;Carlo Beenakker ,&nbsp;Louk Rademaker","doi":"10.1016/j.physc.2025.1354762","DOIUrl":"10.1016/j.physc.2025.1354762","url":null,"abstract":"<div><div>In 1925, Dr. Geertruida Luberta “Berta” de Haas-Lorentz published the paper “<em>Iets over het mechanisme van inductieverschijnselen</em>” in the journal <em>Physica</em>. Her paper was the first to discuss perfect diamagnetism of superconductors, eight years before the discovery of the Meissner effect, when the essential difference between the two phenomena was not understood. Unfortunately, her work was almost forgotten by the scientific community. To counter this, we translate her seminal 1925 paper from Dutch into English. We provide an overview of the life of Dr. De Haas-Lorentz, and comment on her pioneering contribution to the theory of superconductivity.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"635 ","pages":"Article 1354762"},"PeriodicalIF":1.3,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144481246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantum fisher information reveals UV-IR mixing in the strange metal","authors":"David Bałut ,&nbsp;Xuefei Guo ,&nbsp;Niels de Vries ,&nbsp;Dipanjan Chaudhuri ,&nbsp;Barry Bradlyn ,&nbsp;Peter Abbamonte ,&nbsp;Philip W. Phillips","doi":"10.1016/j.physc.2025.1354750","DOIUrl":"10.1016/j.physc.2025.1354750","url":null,"abstract":"<div><div>The density-density response in optimally doped Bi<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Sr<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>CaCu<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O<span><math><msub><mrow></mrow><mrow><mn>8</mn><mo>+</mo><mi>x</mi></mrow></msub></math></span> has recently been shown to exhibit conformal symmetry. Using, the experimentally inferred conformal dynamic susceptibility, we compute the resultant quantum Fisher information (QFI), a witness to multi-partite entanglement. For a Fermi liquid, we find that the QFI grows quadratically as the temperature increases, consistent then with the phase space available for scattering in the standard theory of metals. By contrast, the QFI in a strange metal increases as a power law at as the temperature decreases, but ultimately extrapolates to a constant at <span><math><mrow><mi>T</mi><mo>=</mo><mn>0</mn></mrow></math></span>. The constant is of the form, <span><math><msubsup><mrow><mi>ω</mi></mrow><mrow><mi>g</mi></mrow><mrow><mn>2</mn><mi>Δ</mi></mrow></msubsup></math></span>, where <span><math><mi>Δ</mi></math></span> is the conformal dimension and <span><math><msub><mrow><mi>ω</mi></mrow><mrow><mi>g</mi></mrow></msub></math></span> is the UV cutoff which is on the order of the pseudogap. As this constant depends on both UV and IR properties, it illustrates that multipartite entanglement in a strange metal exhibits UV-IR mixing, a benchmark feature of doped Mott insulators as exemplified by dynamical spectral weight transfer. We conclude with a discussion of the implication of our results for low-energy reductions of the Hubbard model.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"635 ","pages":"Article 1354750"},"PeriodicalIF":1.3,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144307895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corrigendum to “Can dd excitations mediate pairing?” [Physica C: Superconductivity and its Applications 613 (2023) 1354321]","authors":"Francesco Barantani ,&nbsp;Christophe Berthod ,&nbsp;Dirk van der Marel","doi":"10.1016/j.physc.2025.1354753","DOIUrl":"10.1016/j.physc.2025.1354753","url":null,"abstract":"","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"635 ","pages":"Article 1354753"},"PeriodicalIF":1.3,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144212475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Conductivity of strongly disordered ultra-thin MoC superconducting films investigated by transmission line spectroscopy","authors":"Martin Baránek ,&nbsp;Pavol Neilinger ,&nbsp;Daniel Manca ,&nbsp;Oleg G. Turutanov ,&nbsp;Miroslav Grajcar","doi":"10.1016/j.physc.2025.1354749","DOIUrl":"10.1016/j.physc.2025.1354749","url":null,"abstract":"<div><div>The technique of non-contact broadband transmission line flip-chip spectroscopy is utilized to probe resonances of mm-sized square resonators fabricated from strongly disordered molybdenum carbide films in the GHz frequency range. The temperature dependence of the resonances was modeled by the surface impedance of the thin films via the complex conductivity of disordered superconductors, which reflects the Dynes superconducting density of states of these superconductors. The obtained Dynes broadening parameters relate reasonably well to those known from scanning tunneling spectroscopy measurements. The eigenmodes of the 2D resonator were visualized by EM model in Sonnet software.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"635 ","pages":"Article 1354749"},"PeriodicalIF":1.3,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144254404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"How do supercurrents die down when a superconductor goes normal?","authors":"J.E. Hirsch","doi":"10.1016/j.physc.2025.1354747","DOIUrl":"10.1016/j.physc.2025.1354747","url":null,"abstract":"<div><div>The supercurrent flowing near the surface of a type I superconducting body in the presence of an external magnetic field carries kinetic energy and angular momentum. When the macroscopic body transits into the normal state and magnetic field lines start penetrating it, Faraday’s law induces electric currents opposing the change in magnetic flux, that in the aggregate carry kinetic energy and angular momentum many orders of magnitude larger than the supercurrent in the initial state. These currents die down, and their angular momentum is transferred to the body as a whole, without generation of entropy. The conventional theory of superconductivity does not explain how this happens. The alternative theory of hole superconductivity does: it requires carriers with negative effective mass. Our theory also provides an explanation for why flux is generically trapped in type I superconductors under field cooling conditions.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"635 ","pages":"Article 1354747"},"PeriodicalIF":1.3,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144203418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancing Hastelloy tape surfaces flattening efficiency via autonomously designed SDP system derived Y2O3 coatings","authors":"Mingyuan Zhao ,&nbsp;Bowan Tao ,&nbsp;Ruipeng Zhao ,&nbsp;Xi Chen ,&nbsp;Zhenzhe Li ,&nbsp;Tian Xie ,&nbsp;Qichen Wang ,&nbsp;Silong Fang ,&nbsp;Ziwen Jin ,&nbsp;Yudong Xia","doi":"10.1016/j.physc.2025.1354744","DOIUrl":"10.1016/j.physc.2025.1354744","url":null,"abstract":"<div><div>The widespread application of second-generation high-temperature superconducting (2G HTS) tapes has elevated demand for surface smoothing of long-length Hastelloy tapes utilizing simple and low-cost strategies. Amorphous Y₂O₃ has been used to flatten the long-length Hastelloy tape surfaces via solution deposition planarization (SDP). In this work, the autonomously designed SDP system is applied to flatten the Hastelloy surface while significantly increasing progress rate. As a result, lifting speed up to 75 m/h, while the root mean square (RMS) roughness on Hastelloy tape surfaces was reduced from 28.13 nm to 0.76 nm over 5 × 5 μm² areas. These are superior to those of the state-of-the-art SDP lifting speeds. Additionally, the surface flattening process was elaborated through power spectral density (PSD). The Hastelloy tape surfaces have been confirmed to form a well-biaxially textured MgO buffer layer. The autonomously designed SDP system shed light on an effective strategy for flattening long-length Hastelloy tape surfaces.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"634 ","pages":"Article 1354744"},"PeriodicalIF":1.3,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144194698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}