Physica C-superconductivity and Its Applications最新文献

{"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}

{"title":"Tilted solenoids magnet using superconducting stacked tapes","authors":"Junjie Du ,&nbsp;Zhilue Zeng ,&nbsp;Guoshu Zhang ,&nbsp;Kaijun Zhao ,&nbsp;Teng Liu ,&nbsp;Yujie Zhao ,&nbsp;Qi Wu ,&nbsp;Tuxing Zhan","doi":"10.1016/j.physc.2025.1354667","DOIUrl":"10.1016/j.physc.2025.1354667","url":null,"abstract":"<div><div>As a recently developed type of dipole field magnets, the tilted solenoids technology has great potential in various fields such as proton therapy, particle accelerators, and high-field applications. High-temperature superconducting materials can further enhance the magnetic field strength, reduce the bending radius, and lower the device cost. This research is based on differential geometry theory and proposes design methodology along with optimization principle for tilted solenoids magnet utilizing stacked high-temperature superconducting tapes. The engineering implementation strategies for tilted solenoid technology employing superconducting tapes are explored. Both single-turn and multi-turn coils are designed and fabricated respectively, and the critical currents are tested. Additionally, a double-layer tilted solenoids magnet was modeled; magnetic field simulation as well as higher-order analyses were conducted to validate the effectiveness of this methodology.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"630 ","pages":"Article 1354667"},"PeriodicalIF":1.3,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445638","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":"Comparison of critical current and AC loss of 15 MVA superconducting machines with different topologies","authors":"Chao Luo,&nbsp;Jiabo Shou,&nbsp;Jien Ma,&nbsp;Youtong Fang","doi":"10.1016/j.physc.2025.1354664","DOIUrl":"10.1016/j.physc.2025.1354664","url":null,"abstract":"<div><div>Superconducting motors, characterized by their high current-carrying capacity, facilitate the exploration of varied topological designs beyond those possible with traditional motors. Nevertheless, many studies fail to account for the anisotropic properties of superconducting coils, resulting in inaccurate analyses of critical currents and AC losses. This paper introduces a simulation model for 15 MVA superconducting motors employing the H-formulation, which methodically assesses how the configurations of stator and rotor cores impact motor performance. The magnetic behavior of the rotor core, defined through the <span><math><mi>B</mi></math></span>-<span><math><mi>H</mi></math></span> curve derived via the ring sample method, is integrated into the model, enhancing its accuracy. The results reveal that incorporating rotor back core not only reduces the use of superconducting tape but also bolsters the magnetic field adjacent to the coil, thus improving its current-carrying capacity. This approach maximizes output capacity with minimal variations in excitation current. In contrast, including magnetic teeth in the stator curtails superconducting tape consumption and AC losses, it introduces space harmonics that elevate cogging torque. The study determines that the optimal topology combines stator and rotor back core while excluding magnetic teeth in both windings. Finally, a prototype of real-scale racetrack a high-temperature superconducting winding is manufactured, and the critical current within the different core structures is measured to validate its performance.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"630 ","pages":"Article 1354664"},"PeriodicalIF":1.3,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445636","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":"Three-medium treatment of heat transfer in porous media and its application in CICC","authors":"Fengyang Han ,&nbsp;Zhifan Liu ,&nbsp;Zhifeng Liu ,&nbsp;Qiyong Zhang ,&nbsp;Xiaohong Wang ,&nbsp;Min Wang","doi":"10.1016/j.physc.2025.1354650","DOIUrl":"10.1016/j.physc.2025.1354650","url":null,"abstract":"<div><div>In this article, we derive the multi-temperature macroscopic model suitable for the porous CICC structure by using the volume average method. A CICC porous structure usually consists of three phases: one moving fluid phase (typically liquid helium) and two solid phases (typically copper and superconducting alloy). With the assumption of the equal average temperatures of the two solid phases, we obtain a two-temperature macroscopic model. The relevant closure problems are derived and solved numerically for a JT-60SA CICC structure and a ITER-TFPS CICC structure to obtain the macroscopic parameters. The calculated internal heat transfer coefficients are consistent with the experiment results, indicating the accuracy of the proposed two-temperature model. From the proposed two-temperature model, the temperature difference between the fluid and solid phases can be evaluated under a given heat source, which helps to determine whether the one-temperature model can be applied, or the two-temperature model needs to be applied. Typically, the one-temperature model may be suitable for CICC under nominal operation conditions, and the multi-temperature model is necessary during quenching process.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"630 ","pages":"Article 1354650"},"PeriodicalIF":1.3,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445634","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}