Physica C-superconductivity and Its Applications最新文献

{"title":"Numerical approach to calculating binding requirements in high-field STM superconducting magnets","authors":"Zhipeng Jiang ,&nbsp;Hang Zhao ,&nbsp;Lei Yu ,&nbsp;Yuyang Shi ,&nbsp;Jianyuan Xu ,&nbsp;Zhipeng Xu ,&nbsp;Yue Qi ,&nbsp;Zhiyou Chen ,&nbsp;Hangwei Ding ,&nbsp;Pengcheng Huang ,&nbsp;Wenge Chen","doi":"10.1016/j.physc.2025.1354670","DOIUrl":"10.1016/j.physc.2025.1354670","url":null,"abstract":"<div><div>With advancing demands in frontier science, maximizing both the magnetic field strength and diameter of superconducting magnets has become increasingly significant. However, as these parameters grow, the complexity of mechanical analysis for the magnet intensifies. Enhancing the structural stability of superconducting magnets through binding wires is a crucial challenge. Therefore, this paper proposes a numerical method to determine the requirements of binding layers. The finite element numerical method was used to comprehensively analyze the stress generated during the winding, cooling, and excitation of the 12T STM superconducting magnet being developed by the High Magnetic Field Laboratory of China (CHMFL). The required winding forces and number of binding layers for the magnet was determined, effectively improving spatial utilization and preventing shifts or quenching through elasticity theory. This method may also be applied broadly to the mechanical analysis and binding layer determination of other large-aperture, high-field superconducting magnets.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"631 ","pages":"Article 1354670"},"PeriodicalIF":1.3,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143600816","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":"Enhanced mechanical load limit of CORC cable under transverse compression and axial tensile loads","authors":"Jiangtao Yan ,&nbsp;Zhicai Ma ,&nbsp;Yuanwen Gao","doi":"10.1016/j.physc.2025.1354682","DOIUrl":"10.1016/j.physc.2025.1354682","url":null,"abstract":"<div><div>The winding core of CORC (conductor on round core) cables is crucial for resisting mechanical deformations. While different winding core structures can influence the maximum load capacity of these cables, the specific impact of changes in the winding core structure on the mechanical properties of superconducting cables remains unclear. This paper establishes 3D mechanical models of CORC type cables, especially realizes the modeling of the interlocking core structure for the first time and analyzes the mechanical behaviors of these cables under transverse compression and axial tensile loads. It discusses the effects of the winding core structure and the number of inner copper tapes between the winding core and the high-temperature superconducting tape on the mechanical load limits of CORC cables. The results show that CORC cables exhibit enhanced performance in transverse compression and axial tension when a tube core is used for transverse loads and a spiral core for axial loads. The axial strain of the superconducting layer increases as the number of inner copper tapes increases in the transverse compression case, and it decreases as the number of inner copper tapes increases under axial tensile loading. Furthermore, the effect of an arc load block structure on the transverse compression performance of CORC cables is also investigated. The results reveal that the optimal contact angle for achieving optimal transverse compression performance in CORC cables with an arc block structure is approximately 5°. The decrease in the current-carrying capacity of cables in the arc block structure is mainly caused by the combination of compressive strain at the contact area and tensile strain at the contact edges. The numerical results can provide a basis for the reasonable selection of the structure of coil former when the winding CORC coil magnet.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"631 ","pages":"Article 1354682"},"PeriodicalIF":1.3,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143600855","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":"Interfacial superconductivity in Cu/Cu2O and its effect on shielding ambient electric fields","authors":"Dale R. Harshman ,&nbsp;Anthony T. Fiory","doi":"10.1016/j.physc.2024.1354600","DOIUrl":"10.1016/j.physc.2024.1354600","url":null,"abstract":"<div><div>A model is presented for two-dimensional superconductivity at semiconductor-on-metal interfaces mediated by Coulomb interactions between electronically-active interface charges in the semiconductor and screening charges in the metal. The junction considered is native Cu₂O on Cu in which an interfacial double charge layer of areal density <em>n</em>, comprising superconducting holes in Cu₂O and mediating electrons in Cu, is induced in proportion to a sub-monolayer of adsorbed ⁴He atoms. Evidence for superconductivity on copper with prior air exposure is revealed in new analysis of previously published work function data. Based on a theory developed for layered superconductors, the intrinsic transition temperature <em>T</em>_C = β <em>n</em>^1/2/ζ is determined by <em>n</em> and transverse distance ζ ≃ 2.0 Å between the charge layers; β = 1.933(6) <em>e</em>²ƛ_C/<em>k</em>_B = 1247.4(3.7) K-Ų is a universal constant involving the reduced Compton wavelength of the electron ƛ_C. This model is applied to understanding the shielding of copper work-function patch and gravitational compression electric fields reported in the Witteborn-Fairbank gravitational electron free fall experiment. Interfacial superconductivity with <em>n</em> ≃ 1.6 × 10¹² cm⁻², <em>T</em>_C ≃ 7.9 K and Berezinskiĭ-Kosterlitz-Thouless temperature <em>T</em>_BKT ≃ 4.4 K accounts for the shielding observed at temperature <em>T</em> ≃ 4.2 K. Helium desorption and concomitant decreases in <em>n</em> and <em>T</em>_C replicate the temperature transition in ambient electric fields on falling electrons, as observed by Lockhart et al., and the vanishing of superconductivity above <em>T</em> ≃ 4.8 K.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"632 ","pages":"Article 1354600"},"PeriodicalIF":1.3,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143600738","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":"Numerical analysis and experiments of levitation force and bearing stiffness of superconducting magnetic bearings","authors":"Satsuki Okumura ,&nbsp;Kotaro Iida ,&nbsp;Yutaka Terao ,&nbsp;Hiroyuki Ohsaki ,&nbsp;Tomotake Matsumura","doi":"10.1016/j.physc.2025.1354680","DOIUrl":"10.1016/j.physc.2025.1354680","url":null,"abstract":"<div><div>We developed FEM analysis models of superconducting magnetic bearings (SMBs) and analyzed their levitation force and bearing stiffness characteristics. The 2D axisymmetric model is calculated by the <em>A-</em>V<em>-H</em> formulation, and the 3D model is calculated by the <em>H-φ</em> formulation. COMSOL Multiphysics, a general-purpose physics simulation software, was used in the analysis and the power law model was applied to the superconductor's current-voltage characteristics. We also carried out an experiment using a small experimental device of axial type SMB and estimated the levitation force and the bearing stiffness to evaluate the validity of the numerical analysis.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"631 ","pages":"Article 1354680"},"PeriodicalIF":1.3,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143600853","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 and electromagnetic characteristics analysis of high temperature superconducting hybrid electromagnetic support system for high-speed maglev trains","authors":"Chaoqun Jiao,&nbsp;Deming Huang,&nbsp;Lichao Nie,&nbsp;Jin Fang","doi":"10.1016/j.physc.2025.1354685","DOIUrl":"10.1016/j.physc.2025.1354685","url":null,"abstract":"<div><div>The Electromagnetic Suspension (EMS) maglev is a promising solution for local transportation, characterized by its high-speed maglev technology and non-contact with the track. However, it faces challenges such as a limited suspension gap, high energy consumption, and heat dissipation issues. To address these concerns, this article proposes a novel hybrid electromagnetic support system (HESS) that combines high-temperature superconducting and normally conducting materials. By implementing HESS, not only can the suspension gap be increased but also the suspension capacity can be enhanced by 10 %. This paper begins by introducing the design scheme and working principle of HESS before analyzing how different parameter changes (e.g., stator current, excitation current, air gap) affect its electromagnetic performance.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"631 ","pages":"Article 1354685"},"PeriodicalIF":1.3,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143600867","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":"Thoughts about boosting superconductivity","authors":"Dirk van der Marel","doi":"10.1016/j.physc.2025.1354688","DOIUrl":"10.1016/j.physc.2025.1354688","url":null,"abstract":"<div><div>In a superconductor electrons form pairs despite the Coulomb repulsion, as a result of an effective attractive interaction mediated by, for example, phonons. In the present paper DeGennes’ description of the dynamically screened Coulomb interaction is adopted for the effective interaction. This model is generalized by including the elastic response of the charge-compensating background and the BCS gap equation is solved for the resulting effective electron–electron interaction. It is demonstrated that the superconducting critical temperature becomes strongly enhanced when the material is tuned close to a structural instability.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"632 ","pages":"Article 1354688"},"PeriodicalIF":1.3,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143592815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First-principles analysis of superconducting magnesium diboride under pressure using the Cooper pair distribution function Dcp(ω,Tc)","authors":"J.A. Camargo-Martínez ,&nbsp;G.I. González-Pedreros ,&nbsp;C. Vázquez-López","doi":"10.1016/j.physc.2025.1354677","DOIUrl":"10.1016/j.physc.2025.1354677","url":null,"abstract":"<div><div>The Cooper pair distribution function <span><math><mrow><msub><mrow><mi>D</mi></mrow><mrow><mi>c</mi><mi>p</mi></mrow></msub><mrow><mo>(</mo><mi>ω</mi><mo>,</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span> is employed to analyze the behavior of the MgB<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> superconductor under pressures ranging from 8 to 32 GPa. The results of <span><math><mrow><msub><mrow><mi>D</mi></mrow><mrow><mi>c</mi><mi>p</mi></mrow></msub><mrow><mo>(</mo><mi>ω</mi><mo>,</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span> indicate that the formation of Cooper pairs in this compound is highly probable within the energy interval 0–35 meV, where significant vibrational contributions to phonon dispersion arise from both Mg and B atoms. Moreover, the parameters <span><math><msub><mrow><mi>ω</mi></mrow><mrow><mi>c</mi><mi>p</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>N</mi></mrow><mrow><mi>c</mi><mi>p</mi></mrow></msub></math></span> obtained from <span><math><mrow><msub><mrow><mi>D</mi></mrow><mrow><mi>c</mi><mi>p</mi></mrow></msub><mrow><mo>(</mo><mi>ω</mi><mo>,</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span> accurately replicate the pressure dependence of the superconducting critical temperature T<span><math><msub><mrow></mrow><mrow><mi>c</mi></mrow></msub></math></span> observed in MgB<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>. This provides a possible phenomenological explanation for its highest experimentally measured T<span><math><msub><mrow></mrow><mrow><mi>c</mi></mrow></msub></math></span>. An electronic analysis of <span><math><mrow><msub><mrow><mi>D</mi></mrow><mrow><mi>c</mi><mi>p</mi></mrow></msub><mrow><mo>(</mo><mi>ω</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> function below the Fermi level reveals initial consistency with both theoretical and experimental results for the superconducting gap energy in MgB<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>. These findings demonstrate that <span><math><mrow><msub><mrow><mi>D</mi></mrow><mrow><mi>c</mi><mi>p</mi></mrow></msub><mrow><mo>(</mo><mi>ω</mi><mo>,</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span> is a promising theoretical tool for studying conventional superconductors.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"632 ","pages":"Article 1354677"},"PeriodicalIF":1.3,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143621485","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 significance of “stripes” in the physics of the cuprates, the Hubbard model, and other highly correlated electronic systems","authors":"Thomas P. Devereaux ,&nbsp;Steven A. Kivelson","doi":"10.1016/j.physc.2025.1354683","DOIUrl":"10.1016/j.physc.2025.1354683","url":null,"abstract":"<div><div>“Stripes”— meaning unidirectional charge-density-waves, sometimes (but not always) accompanied by spin-density-waves with twice the period - are now known to arise in broad swathes of the cuprate phase diagram, and appear as a strong ordering tendency in numerical studies of Hubbard-like models of highly correlated electron systems. Jan Zaanen’s work played a seminal role in predicting their existence, and exploring their possible significance. They are <em>not</em> related to any weak-coupling physics associated with some form of Fermi-surface nesting. And whether one likes them or not, they are surprisingly difficult to avoid; in the Hubbard model, for example, they often appear as an alternative order that can out-compete the otherwise favored <span><math><mi>d</mi></math></span>-wave superconductivity.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"632 ","pages":"Article 1354683"},"PeriodicalIF":1.3,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143562705","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":"Effects of extrinsic parameters on superconducting nanowire single-photon detector output – A study towards developing read-out circuit","authors":"Amit Soni ,&nbsp;Anish M. Bhargav ,&nbsp;Pratiksha Pratap ,&nbsp;V.N. Singh","doi":"10.1016/j.physc.2025.1354689","DOIUrl":"10.1016/j.physc.2025.1354689","url":null,"abstract":"<div><div>A superconducting nanowire single-photon detector (SNSPD) is an optoelectrical device that works on the concept of hotspot formation and can detect a single photon. The associated readout circuit plays a vital role in determining the response of SNSPD. The available resources, complexity, and costs are major limiting factors in the actual readout circuit design. The preliminary information about the extrinsic effects that alter the SNSPD output from its desired value helps fabricate readout circuits. Here, the electrical equivalent circuit (EEC) for SNSPD has been simulated using LT spice software, and accordingly, a model has been developed to understand the readout circuit requirements. The EEC has been tested at room temperature by varying parameters like pulse width, bias voltage, capacitance and inductance. In addition, we have also designed and simulated a circuit for the multi-pixel photon counting scheme using a frequency multiplexing technique. Utilising this scheme, we observed that each EEC could be distinguished by its unique resonance frequency, reducing circuit complexity and power consumption. The results obtained indicate that their unique resonance frequency can identify triggered EEC.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"632 ","pages":"Article 1354689"},"PeriodicalIF":1.3,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143579416","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 influence of the additional coil and ferromagnetic rings on high-temperature superconducting engine magnets","authors":"Wei Liu ,&nbsp;Wentao Zhang ,&nbsp;Weiwei Zhang ,&nbsp;Yongbin Wang ,&nbsp;Haowei Wu ,&nbsp;Donghui Liu","doi":"10.1016/j.physc.2025.1354665","DOIUrl":"10.1016/j.physc.2025.1354665","url":null,"abstract":"<div><div>A plasma engine with high-temperature superconducting (HTS) tapes offers advantages such as high efficiency, high thrust, and high specific impulse. However, due to the magnetic field-dependent characteristics of HTS tapes, the magnetic field at the coil ends tends to decrease rapidly. To mitigate this issue, a small additional coil can be wound at the coil end to enhance the magnetic field, or ferromagnetic rings can be employed to modify the local magnetic flux lines direction within the superconductor, thereby reducing the impact of radial magnetic fields on the critical current of the HTS tapes. In this study, to analyze the effects of the additional coil and ferromagnetic rings, a two-dimensional axisymmetric numerical model is established, and the T-A formulation is utilized to investigate the axial centerline magnetic field distribution of the HTS engine magnet. The simulation results indicate that varying the coil current primarily affects the peak value of the magnetic field without altering its configuration. The addition of an additional coil at the coil end effectively mitigates the rapid decline in the magnetic field at the coil end. The results also indicate that adding ferromagnetic rings can reduce the influence of the radial magnetic field on the critical current, thus enhancing the magnetic field at the coil ends. Furthermore, the results of the radial magnetic field distribution at the end of Coil-4 indicate that ferromagnetic rings can significantly reduce the magnitude of the radial magnetic field at the coil surface.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"630 ","pages":"Article 1354665"},"PeriodicalIF":1.3,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445637","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}