A novel superconductor of (AuxCu1-x)Sr2CaCu2Oy ((Au,Cu)-1(Sr)212) was synthesized by oxidation of Au at 5.5 GPa and 980–1030 °C. The crystal structure of (Au,Cu)-1(Sr)212 was analyzed using X-ray diffraction (XRD) and field emission transmission electron microscopy (FE-TEM). From XRD results, the (Au,Cu)-1(Sr)212 with lattice parameters of a ≈ 3.86 Å, c ≈ 10.98 Å, respectively, were observed. A superconducting signal was observed below T = 29.7 K in the magnetic susceptibility measurements.
{"title":"Synthesis novel (AuxCu1-x)Sr2CaCu2Oy superconductor under high pressure","authors":"Zhenlei Feng , Thi-Mai-Dung Do , Tadachika Nakayama , Tomoya Aoba , Hisayuki Suematsu , Koichi Niihara","doi":"10.1016/j.physc.2025.1354777","DOIUrl":"10.1016/j.physc.2025.1354777","url":null,"abstract":"<div><div>A novel superconductor of (AuxCu1-x)Sr2CaCu2Oy ((Au,Cu)-1(Sr)212) was synthesized by oxidation of Au at 5.5 GPa and 980–1030 °C. The crystal structure of (Au,Cu)-1(Sr)212 was analyzed using X-ray diffraction (XRD) and field emission transmission electron microscopy (FE-TEM). From XRD results, the (Au,Cu)-1(Sr)212 with lattice parameters of <em>a</em> ≈ 3.86 Å, <em>c</em> ≈ 10.98 Å, respectively, were observed. A superconducting signal was observed below <em>T</em> = 29.7 K in the magnetic susceptibility measurements.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"636 ","pages":"Article 1354777"},"PeriodicalIF":1.0,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144723879","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}
Polycrystalline superconductor was oxidized by ozone to improve its superconducting property. Zero resistivity was observed below = 52 K, and diamagnetism was observed below = 70 K. After the sample was ozonized, and increased by 10 and 14 K, respectively. The critical current density in individual grains at 2 K under a 0.1 T field was deduced to be from the magnetization curve, which was 38 times greater than that of a sample annealed under a high pressure.
{"title":"Effect of ozone annealing on FeSr2YCu2O6+y superconductor","authors":"Yoshiaki Hata , Shun Taguchi , Takashi Mochiku , Hiroshi Yasuoka","doi":"10.1016/j.physc.2025.1354766","DOIUrl":"10.1016/j.physc.2025.1354766","url":null,"abstract":"<div><div>Polycrystalline <span><math><mrow><msub><mrow><mi>FeSr</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>YCu</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>O</mi></mrow><mrow><mn>6</mn><mo>+</mo><mi>y</mi></mrow></msub></mrow></math></span> superconductor was oxidized by ozone to improve its superconducting property. Zero resistivity was observed below <span><math><msubsup><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow><mrow><mi>zero</mi></mrow></msubsup></math></span> = 52 K, and diamagnetism was observed below <span><math><msubsup><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow><mrow><mi>MT</mi></mrow></msubsup></math></span> = 70 K. After the sample was ozonized, <span><math><msubsup><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow><mrow><mi>zero</mi></mrow></msubsup></math></span> and <span><math><msubsup><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow><mrow><mi>MT</mi></mrow></msubsup></math></span> increased by 10 and 14 K, respectively. The critical current density in individual grains at 2 K under a 0.1 T field was deduced to be <span><math><mrow><mn>1</mn><mo>.</mo><mn>3</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>11</mn></mrow></msup><msup><mrow><mi>A/m</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></math></span> from the magnetization curve, which was 38 times greater than that of a sample annealed under a high <span><math><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> pressure.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"636 ","pages":"Article 1354766"},"PeriodicalIF":1.0,"publicationDate":"2025-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144737952","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}
The underdoped cuprate superconductors are characterized by the opening of the normal-state pseudogap, while such an aspect of the normal-state pseudogap effect should be reflected in the low-energy electronic structure. Here the effect of the normal-state pseudogap on the low-energy electronic structure in the underdoped cuprate superconductors is investigated within the framework of the kinetic-energy-driven superconductivity. The strong coupling of the electrons with the spin excitation induces the normal-state pseudogap-state in the particle-hole channel and superconducting (SC) state in the particle–particle channel, where the normal-state pseudogap and SC gap respectively originate from the electron normal and anomalous self-energies, and are evaluated by taking into account the vertex correction. As a natural consequence of the interplay between the normal-state pseudogap-state and SC-state, the SC transition temperature exhibits a dome-like shape of the doping dependence, however, in a striking contrast to in the underdoped regime, the normal-state pseudogap crossover temperature is much higher than in the underdoped regime, and then it decreases with the increase of doping, eventually disappearing together with at the end of the SC dome. Concomitantly, the spectral weight on the electron Fermi surface (EFS) at around the antinodal region is suppressed strongly by this normal-state pseudogap, and then EFS is truncated to form four disconnected Fermi arcs centered around the nodal region with the largest spectral weight located at around the tips of the disconnected Fermi arcs. Moreover, the dip in the peak-dip-hump structure observed in the energy distribution curve and checkerboard charge ordering found in the ARPES autocorrelation are intrinsically connected with the emergence of the normal-state pseudogap. The theory therefore indicates that the same spin excitation that governs both the normal-state pseudogap-state and SC-state naturally leads to the exotic features of the low-energy electronic structure in the underdoped cuprate superconductors.
{"title":"Unusual electronic structure in underdoped cuprate superconductors","authors":"Xiang Li , Minghuan Zeng , Huaiming Guo , Shiping Feng","doi":"10.1016/j.physc.2025.1354767","DOIUrl":"10.1016/j.physc.2025.1354767","url":null,"abstract":"<div><div>The underdoped cuprate superconductors are characterized by the opening of the normal-state pseudogap, while such an aspect of the normal-state pseudogap effect should be reflected in the low-energy electronic structure. Here the effect of the normal-state pseudogap on the low-energy electronic structure in the underdoped cuprate superconductors is investigated within the framework of the kinetic-energy-driven superconductivity. The strong coupling of the electrons with the spin excitation induces the normal-state pseudogap-state in the particle-hole channel and superconducting (SC) state in the particle–particle channel, where the normal-state pseudogap and SC gap respectively originate from the electron normal and anomalous self-energies, and are evaluated by taking into account the vertex correction. As a natural consequence of the interplay between the normal-state pseudogap-state and SC-state, the SC transition temperature <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> exhibits a dome-like shape of the doping dependence, however, in a striking contrast to <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> in the underdoped regime, the normal-state pseudogap crossover temperature <span><math><msup><mrow><mi>T</mi></mrow><mrow><mo>∗</mo></mrow></msup></math></span> is much higher than <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> in the underdoped regime, and then it decreases with the increase of doping, eventually disappearing together with <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> at the end of the SC dome. Concomitantly, the spectral weight on the electron Fermi surface (EFS) at around the antinodal region is suppressed strongly by this normal-state pseudogap, and then EFS is truncated to form four disconnected Fermi arcs centered around the nodal region with the largest spectral weight located at around the tips of the disconnected Fermi arcs. Moreover, the dip in the peak-dip-hump structure observed in the energy distribution curve and checkerboard charge ordering found in the ARPES autocorrelation are intrinsically connected with the emergence of the normal-state pseudogap. The theory therefore indicates that the same spin excitation that governs both the normal-state pseudogap-state and SC-state naturally leads to the exotic features of the low-energy electronic structure in the underdoped cuprate superconductors.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"636 ","pages":"Article 1354767"},"PeriodicalIF":1.3,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144678805","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}
Pub Date : 2025-07-15DOI: 10.1016/j.physc.2025.1354755
Zohar Nussinov , Saurish Chakrabarty
We introduce “local uncertainty relations” in thermal quantum many-body systems from which fundamental bounds can be derived. These inequalities imply rigorous universal non-relativistic speed limits (independent of interaction range) and, as we focus on in the current work, bounds associated with transport (e.g., the diffusion constant and shear viscosity). Using the chaos bounds and other considerations, we introduce simplified non-rigorous universal transport coefficient inequalities and compare our resulting bounds against experimental data.
{"title":"Planckian bounds from local uncertainty relations","authors":"Zohar Nussinov , Saurish Chakrabarty","doi":"10.1016/j.physc.2025.1354755","DOIUrl":"10.1016/j.physc.2025.1354755","url":null,"abstract":"<div><div>We introduce “<em>local uncertainty relations</em>” in thermal quantum many-body systems from which fundamental bounds can be derived. These inequalities imply rigorous universal non-relativistic speed limits (independent of interaction range) and, as we focus on in the current work, bounds associated with transport (e.g., the diffusion constant and shear viscosity). Using the chaos bounds and other considerations, we introduce simplified non-rigorous universal transport coefficient inequalities and compare our resulting bounds against experimental data.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"636 ","pages":"Article 1354755"},"PeriodicalIF":1.3,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144623704","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}
Pub Date : 2025-07-10DOI: 10.1016/j.physc.2025.1354743
Jolly Andrews , Remya U.D. , Ajith Ramachandran , Joseph V.P. , Vincent Mathew
The electromagnetic response of a high temperature superconducting (HTS) slotline placed in a static magnetic field at varying oblique angles is analyzed using propagation parameters computed by spectral domain method (SDM). The modified two-fluid theory formulated by Coffey and Clem (CC) for the angular dependence is employed to self-consistently determine the vortex dynamical response of the HTS films made of different material purities. The impedance matrix of the slotline obtained using SDM is modified by incorporating the HTS contribution and Galerkin technique is used for the calculation of the propagation parameters. The paper presents the angular dependence of the obliquely angled static magnetic field on signal propagation and explains the results using vortex dynamic effects.
{"title":"Spectral domain modeling of superconducting slotline in the presence an oblique applied static magnetic field","authors":"Jolly Andrews , Remya U.D. , Ajith Ramachandran , Joseph V.P. , Vincent Mathew","doi":"10.1016/j.physc.2025.1354743","DOIUrl":"10.1016/j.physc.2025.1354743","url":null,"abstract":"<div><div>The electromagnetic response of a high temperature superconducting (HTS) slotline placed in a static magnetic field at varying oblique angles is analyzed using propagation parameters computed by spectral domain method (SDM). The modified two-fluid theory formulated by Coffey and Clem (CC) for the angular dependence is employed to self-consistently determine the vortex dynamical response of the HTS films made of different material purities. The impedance matrix of the slotline obtained using SDM is modified by incorporating the HTS contribution and Galerkin technique is used for the calculation of the propagation parameters. The paper presents the angular dependence of the obliquely angled static magnetic field on signal propagation and explains the results using vortex dynamic effects.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"635 ","pages":"Article 1354743"},"PeriodicalIF":1.3,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144588736","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}
Pub Date : 2025-07-10DOI: 10.1016/j.physc.2025.1354751
He Ding , Lintao Li , Qian Li , Yuanwen Gao
The state-of-the-art Nb3Sn wire still exhibits discrepancies in both mechanical and superconducting critical properties when juxtaposed with the target of the requirement for superconducting wire set for future circular colliders (FCC). Intensive efforts are currently underway to develop high performance Nb3Sn wires with enhanced mechanical and superconducting properties. In parallel, developing convenient and efficient numerical methods for comprehensively evaluating the mechanical and superconducting properties of various Nb3Sn wires is of critical significance. Given the relevant context, the analysis of critical current degradation and fracture damage behavior of Nb3Sn superconducting wires under transverse pressure is of significant importance. In this paper, the detailed strand numerical models are established based on the meso‑structure characteristics of Restacked-Rod-Process (RRP) and Powder-in-tube (PIT) Nb3Sn wires at first. These models can be used to simulate stress distribution and mechanical behaviors under various external loading conditions. Subsequently, the damage and superconducting critical current degradation of epoxy-impregnated RRP and PIT wires under transverse pressure are evaluated in numerical simulations, taking into account the irreversible degradation caused by the residual plastic stress of the annealed copper matrix. This numerical method encodes all superconducting filaments/sub-elements of the two-dimensional numerical model by considering the periodic positional changes of the twisted filaments/sub-elements along the wire axis. The results indicate that within a transverse pressure range of 100 to 200 MPa, the plastic residual stress of the copper matrix is the primary cause of irreversible critical current degradation. At transverse pressure exceeding 200 MPa, the influence of damage on the critical current cannot be ignored due to the emergence of damage. When the transverse pressure reaches 413 MPa, through-thickness damage has occurred in the Nb3Sn phase of all types RRP and PIT wires. Compared to PIT B215 wires, the critical current of RRP 108/127 wires have better strain tolerance. The numerical method with a low computational burden in this paper can conveniently evaluate the fracture and damage as well as degradation of critical properties of various Nb3Sn wires under transverse pressure.
{"title":"Numerical simulation of damage and critical current degradation behaviors of RRP and PIT Nb3Sn wires under transverse pressure","authors":"He Ding , Lintao Li , Qian Li , Yuanwen Gao","doi":"10.1016/j.physc.2025.1354751","DOIUrl":"10.1016/j.physc.2025.1354751","url":null,"abstract":"<div><div>The state-of-the-art Nb<sub>3</sub>Sn wire still exhibits discrepancies in both mechanical and superconducting critical properties when juxtaposed with the target of the requirement for superconducting wire set for future circular colliders (FCC). Intensive efforts are currently underway to develop high performance Nb<sub>3</sub>Sn wires with enhanced mechanical and superconducting properties. In parallel, developing convenient and efficient numerical methods for comprehensively evaluating the mechanical and superconducting properties of various Nb<sub>3</sub>Sn wires is of critical significance. Given the relevant context, the analysis of critical current degradation and fracture damage behavior of Nb<sub>3</sub>Sn superconducting wires under transverse pressure is of significant importance. In this paper, the detailed strand numerical models are established based on the meso‑structure characteristics of Restacked-Rod-Process (RRP) and Powder-in-tube (PIT) Nb<sub>3</sub>Sn wires at first. These models can be used to simulate stress distribution and mechanical behaviors under various external loading conditions. Subsequently, the damage and superconducting critical current degradation of epoxy-impregnated RRP and PIT wires under transverse pressure are evaluated in numerical simulations, taking into account the irreversible degradation caused by the residual plastic stress of the annealed copper matrix. This numerical method encodes all superconducting filaments/sub-elements of the two-dimensional numerical model by considering the periodic positional changes of the twisted filaments/sub-elements along the wire axis. The results indicate that within a transverse pressure range of 100 to 200 MPa, the plastic residual stress of the copper matrix is the primary cause of irreversible critical current degradation. At transverse pressure exceeding 200 MPa, the influence of damage on the critical current cannot be ignored due to the emergence of damage. When the transverse pressure reaches 413 MPa, through-thickness damage has occurred in the Nb<sub>3</sub>Sn phase of all types RRP and PIT wires. Compared to PIT B215 wires, the critical current of RRP 108/127 wires have better strain tolerance. The numerical method with a low computational burden in this paper can conveniently evaluate the fracture and damage as well as degradation of critical properties of various Nb<sub>3</sub>Sn wires under transverse pressure.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"635 ","pages":"Article 1354751"},"PeriodicalIF":1.3,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144588739","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}
Pub Date : 2025-07-10DOI: 10.1016/j.physc.2025.1354765
Vladimir Sokolovsky , Leonid Prigozhin
Ferromagnetic substrates can significantly influence the electromagnetic response of a coated conductor to an external magnetic field and transport current. This study analyzes this response theoretically using the thin shell integrodifferential model. First, assuming the substrate is strongly magnetic and the superconductor is in the Meissner state, we present the analytical solution in a convenient explicit form. This helps us to analyze the superconducting current density distributions, highlighting their differences from those in conductors with non-magnetic substrates. Second, we consider a superconducting layer characterized by a nonlinear current-voltage relation and a substrate with a finite field-independent magnetic permeability. We use an effective spectral numerical method to study the unique features of this hybrid superconductor/ferromagnet system, such as magnetization in a parallel external field and the peculiar nonmonotonic variation of loss observed when alternating transport current and parallel field are applied simultaneously. Dynamic losses for the case of a direct transport current and an alternating parallel field are also investigated. It is shown that tuning the phase and amplitude of the applied parallel field relative to those of the transport current can reduce AC losses.
{"title":"Electromagnetic analysis of coated conductors with ferromagnetic substrates: Novel insights","authors":"Vladimir Sokolovsky , Leonid Prigozhin","doi":"10.1016/j.physc.2025.1354765","DOIUrl":"10.1016/j.physc.2025.1354765","url":null,"abstract":"<div><div>Ferromagnetic substrates can significantly influence the electromagnetic response of a coated conductor to an external magnetic field and transport current. This study analyzes this response theoretically using the thin shell integrodifferential model. First, assuming the substrate is strongly magnetic and the superconductor is in the Meissner state, we present the analytical solution in a convenient explicit form. This helps us to analyze the superconducting current density distributions, highlighting their differences from those in conductors with non-magnetic substrates. Second, we consider a superconducting layer characterized by a nonlinear current-voltage relation and a substrate with a finite field-independent magnetic permeability. We use an effective spectral numerical method to study the unique features of this hybrid superconductor/ferromagnet system, such as magnetization in a parallel external field and the peculiar nonmonotonic variation of loss observed when alternating transport current and parallel field are applied simultaneously. Dynamic losses for the case of a direct transport current and an alternating parallel field are also investigated. It is shown that tuning the phase and amplitude of the applied parallel field relative to those of the transport current can reduce AC losses.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"635 ","pages":"Article 1354765"},"PeriodicalIF":1.3,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144588741","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}
Pub Date : 2025-07-10DOI: 10.1016/j.physc.2025.1354761
Tianyu Xing , Jinkai Zhang , Yan Li , Can Peng , Peiyu Yin , Zigang Deng
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 %.
{"title":"Optimization of the Halbach permanent magnet guideway in HTS maglev based on sensitivity analysis","authors":"Tianyu Xing , Jinkai Zhang , Yan Li , Can Peng , Peiyu Yin , 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}
Pub Date : 2025-07-10DOI: 10.1016/j.physc.2025.1354764
Meng Han , Chao Yao , Dongliang Wang , He Huang , Chiheng Dong , Xianping Zhang , Yanwei Ma
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 BaxK1-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.
{"title":"The inhomogeneous flow behavior of in iron-based superconducting tape production: Formation mechanism and impact on transport performance","authors":"Meng Han , Chao Yao , Dongliang Wang , He Huang , Chiheng Dong , Xianping Zhang , 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<sub>x</sub>K<sub>1-x</sub>Fe<sub>2</sub>As<sub>2</sub> (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}
Pub Date : 2025-07-10DOI: 10.1016/j.physc.2025.1354718
Gang He , Yi Zhu , Wenjie Yang , Yu Liang , Yiqin Lei , Yanbing Yang , Pengshan Chang , Lizhen Ma , Guangquan Chen , Kedong Wang , Xu Zhang , Kai Wang , Tianfa Liao
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 [1], [2], [3], [4], [5], 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.
{"title":"Design of superconducting magnets for high energy beam transport lines for proton cancer therapy","authors":"Gang He , Yi Zhu , Wenjie Yang , Yu Liang , Yiqin Lei , Yanbing Yang , Pengshan Chang , Lizhen Ma , Guangquan Chen , Kedong Wang , Xu Zhang , Kai Wang , 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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号