Physica C-superconductivity and Its Applications最新文献

{"title":"Electron, phonon, and superconducting properties of Mg2CuH6 under pressure","authors":"Juan Gao ,&nbsp;Qi-Jun Liu ,&nbsp;Dai-He Fan ,&nbsp;Zheng-Tang Liu","doi":"10.1016/j.physc.2024.1354571","DOIUrl":"10.1016/j.physc.2024.1354571","url":null,"abstract":"<div><p>Recent theoretical prediction of Mg₂IrH₆ is a significant advance in achieving high-temperature superconductivity under atmospheric pressure, Mg₂IrH₆ is the hydride superconductor with the highest superconducting transition temperature (<em>T</em>_c ∼ 160 K) under ambient pressure so far. In general, <em>T</em>_c is usually related to the degree of hydrogen enrichment. As a representative of the hydrogen-poor structures, MgHCu₃ was also predicted to have a <em>T</em>_c of 43 K under atmospheric pressure. In this work, we try to replace the Ir atom in Mg₂IrH₆ with the Cu atom to improve the superconductivity of the system. The phonon dispersion curves and the <em>ab initio</em> molecular dynamics (AIMD) simulation indicate that the novel ternary Mg₂CuH₆ hydride is dynamically and thermodynamically stable. But, regrettably, the <em>T</em>_c and electron-phonon coupling (EPC) parameters λ of Mg₂CuH₆ are calculated to be 12.5 K and 0.55 at 25 GPa, which is far inferior to the superconductivity of Mg₂IrH₆. Compared with <span><math><mrow><mi>F</mi><mi>m</mi><mover><mn>3</mn><mo>¯</mo></mover><mi>m</mi></mrow></math></span> Mg₂CuH₆, <span><math><mrow><mi>F</mi><mi>m</mi><mover><mn>3</mn><mo>¯</mo></mover><mi>m</mi></mrow></math></span> Mg₂IrH₆ produces obvious phonon softening in the G point near 30 meV, which significantly enhances the EPC and increases the <em>T</em>_c of the system. Moreover, Cu substitution for Ir results in a sharp decrease in the contribution of the electronic states for Mg and H to the total density of states at the Fermi level. The huge difference in predicted <em>T</em>_c between Mg₂CuH₆ and Mg₂IrH₆ and their causes may provide insights into the design of high-temperature atmospheric superconductors and help to understand the superconducting mechanisms of related systems.</p></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"624 ","pages":"Article 1354571"},"PeriodicalIF":1.3,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141701752","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 Sm2O3 nanoparticles adding on some superconducting properties of Bi1.6Pb0.4Sr2Ca2Cu3O10+δ ceramics","authors":"Maryam Saghafi,&nbsp;Gholamabbas Shams,&nbsp;Zahra Soltani","doi":"10.1016/j.physc.2024.1354566","DOIUrl":"10.1016/j.physc.2024.1354566","url":null,"abstract":"&lt;div&gt;&lt;p&gt;High-Temperature Superconductors Bi&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;6&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;Pb&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;4&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;Sr&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;Ca&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;Cu&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;O&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;10&lt;/mn&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mi&gt;δ&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; samples doped with Sm&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;O&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; nanoparticles in different quantities (0.00, 0.02, 0.04 and 0.06), were synthesised. Solid state feedback technique was used to prepare the samples and then characterised. The morphology and structure of the specimens were deployed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) examination. The spectroscopy of the energy dispersive X-ray (EDX) experiment was utilised to obtain the elemental composition of the samples. Resistivity versus temperature measurement in DC mode was employed to estimate the critical transition temperature of each sample. XRD with the Rietveld refinement process revealed that Bi2223 and Bi2212 stages exist mutually in specimens with orthorhombic crystal systems. The lowest percentage of volume fraction associated with the Bi2223 phase belonged to the sample with &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;06&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; nanoparticle samarium doped. It was detected that with rising samarium content the volume division of the Bi2223 phase decreases but the Bi2212 stage increases compared with the pristine specimen. SEM showed that the shrinkage of grain size occurs when the amount of nano-sized Sm was added to &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;02&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; sample with lower inter-coupling among superconducting granules. This effect might be verified by SEM and TEM images. EDX exhibited some peaks related to Sm and other elements of the Bi2223 structure. These patterns confirm that all elements associated with the compounds were introduced into the Bi2223 matrix. The critical temperatures such as &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mi&gt;o&lt;/mi&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;mi&gt;s&lt;/mi&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;, &lt;span&gt;&lt;math&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;mi&gt;k&lt;/mi&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mi&gt;z&lt;/mi&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;mi&gt;o&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; decreased for Sm doped samples compared with the pure sample. Adding Sm&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;O&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"624 ","pages":"Article 1354566"},"PeriodicalIF":1.3,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141736575","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":"Investigating the impact of magnetic air gap variations on short circuit characteristics of partially high temperature superconducting generator","authors":"Mohamed Elhindi ,&nbsp;Modawy Adam Ali Abdalla ,&nbsp;Dong Liu","doi":"10.1016/j.physc.2024.1354550","DOIUrl":"https://doi.org/10.1016/j.physc.2024.1354550","url":null,"abstract":"<div><p>Partially high-temperature superconducting generators (PHTSGs) feature large magnetic air gaps imposed by using cryostats for HTS field windings. This increased air gap significantly affects end winding inductance and can lead to elevated fault torque levels. This study investigates the influence of magnetic air gap variation on generator design and end winding inductance and its implications for short-circuit faults in PHTSGs. Through a combination of numerical simulations and analytical analysis, the study explores how changes in the magnetic air gap affect end winding inductance and subsequently influence short-circuit fault behavior. The results reveal a direct correlation between magnetic air gap length, end winding inductance, and key short-circuit parameters such as stator current, field currents, and electromagnetic torque. Notably, an increase in the magnetic air gap is observed to elevate stator and field currents and electromagnetic torque during short-circuit events. These insights underscore the importance of considering magnetic air gap variation and its impact on end winding inductance and its relationship with short circuit characteristics in the design and operation of PHTSGs, providing valuable insights for enhancing the resilience and performance of high-temperature superconductor-based generator systems.</p></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"623 ","pages":"Article 1354550"},"PeriodicalIF":1.3,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141541982","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":"Thermal analysis of the HTS transformer in the fault current condition considering the tape roughness effect","authors":"Mahdi Mahamed,&nbsp;Seyyedmeysam Seyyedbarzegar","doi":"10.1016/j.physc.2024.1354548","DOIUrl":"https://doi.org/10.1016/j.physc.2024.1354548","url":null,"abstract":"<div><p>High temperature superconducting (HTS) transformers have many advantages over conventional transformers in terms of volume, weight, and total efficiency. However, fault conditions limit the electro-thermal performance of an HTS transformer. Based on this, we investigate the thermal modeling of the HTS transformer in the fault-current state. For thermal modeling, heat transfer and parameters affecting it such as surface roughness and bubble behavior have been considered. At first, an accurate thermal model for a 10 kVA HTS transformer has been prepared. Experimental results show that the penalty of this model is about 2.5 K in the hot-spot point (HSP) temperature in fault-current conditions. In a second step, the impact of a roughness on the heat transfer and mass transfer rate in nucleated boiling mode is investigated. Results show that surface roughness decreases the HSP temperature by more than 10 K in fault-current conditions. These results have significant impacts on protecting HTS windings against quenching.</p></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"623 ","pages":"Article 1354548"},"PeriodicalIF":1.3,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141541981","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":"Evidences for d-wave symmetry of c-axis superconducting gap in atomically thin twisted flakes of bismuth-based HTS cuprates","authors":"Evgeny F. Talantsev","doi":"10.1016/j.physc.2024.1354549","DOIUrl":"https://doi.org/10.1016/j.physc.2024.1354549","url":null,"abstract":"<div><p><em>c</em>-axis Josephson tunnelling in atomically thin twisted flakes of quasi-two-dimensional cuprate superconductors is one of the experimental techniques which can be used to reveal the pairing symmetry in HTS cuprates. Until very recent experiments reported by Zhao et al. (<em>Science</em> <strong>382</strong>, 1422 (2023)), there was a widely accepted consensus that the <em>c</em>-axis Josephson currents, <em>I</em>_c(<em>T</em>), in twisted cuprate junctions manifest the <em>s</em>-wave gap symmetry for <em>c</em>-axis gap component. Here, I highlighted that this consensus was based on the analysis of the <em>I</em>_c(<em>T</em>) data by using the Ambegaokar-Baratoff equation, where the weak-coupling s-wave gap equation was utilized. In this study, I introduced a more accurate gap equation in the AB model and reanalyzed the <em>I</em>_c(<em>T</em>) data in atomically thin twisted Bi₂Sr_2-xLa_xCuO₆₊<em>_y</em> (Bi-2201) and Bi₂Sr₂CaCu₂O₈₊<em>_x</em> (Bi-2212) flakes. In the result, the analysis revealed evidences for <em>d</em>-wave pairing symmetry. Beside this, the analysis of the <em>R</em>_n<em>I</em>_c(<em>T</em>) data reported by Zhao et al. (<em>Science</em> <strong>382</strong>, 1422 (2023)) by a piecewise AB model, where a linear low-<em>T</em> dependence of the <em>I</em>_c(<em>T</em>) is used, and where the threshold temperature <em>T</em>_M is a free-fitting parameter, confirmed the <em>d</em>-wave symmetry in these twisted Bi-2212 junctions.</p></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"623 ","pages":"Article 1354549"},"PeriodicalIF":1.3,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141483710","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":"Magnetic and mechanical analyses of superconducting coil for the magnetic Czochralsky technique","authors":"Mohmmed Mun ELseed Hassaan ,&nbsp;Wanjiang Pan ,&nbsp;Yinfeng Zhu ,&nbsp;Mo Shen ,&nbsp;Cheng Wu","doi":"10.1016/j.physc.2024.1354545","DOIUrl":"https://doi.org/10.1016/j.physc.2024.1354545","url":null,"abstract":"<div><p>Solar cells, electronics, and the semiconductor industry all need high-quality silicon crystals. The Czochralsky technique has been widely used to make a high-quality single silicon crystal from the silicon melt. However, this technique needs a strong magnetic field to stabilize the melt and control the temperature. In this paper, two coils with a curved shape have been optimized and simulated to produce a transverse magnetic field for the Czochralsky technique grower. The coils face each other and have an opening angle of 150°, and a NbTi superconducting wire was used to wind the coils with 5110 turns. The current was 106 A and flowing in the same direction. The finding results indicated that the magnetic field at the silicon melt center is 0.4 T, and the peak field in coils is 2.95 T. The optimized curve shape coils were compared with conventional coils (circle shape coils). The comparison indicated that the curve shape coils produced a highly uniform magnetic field, required less current, and significantly reduced the outer diameter of the superconducting magnet. In addition, heat generation by the current leads was calculated. In the case of the curve-shaped coils, less heat leakage has been achieved; as a result, the cooling capacity, magnet size, weight, and cost will be reduced. Furthermore, mechanical analysis was performed, and the results showed that the stress in the coils is within the permissible range for NbTi at 4.2 K.</p></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"624 ","pages":"Article 1354545"},"PeriodicalIF":1.3,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141482613","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":"Preparation of a/c-oriented YBa2Cu3O7−x homogeneous superconducting junctions via pulsed laser deposition","authors":"Xiaoqin Liu ,&nbsp;Yeming He ,&nbsp;Peng Li ,&nbsp;Wei Li ,&nbsp;Yangyang Wang ,&nbsp;Mingyang Zhou","doi":"10.1016/j.physc.2024.1354551","DOIUrl":"https://doi.org/10.1016/j.physc.2024.1354551","url":null,"abstract":"<div><p>The growth orientation of YBa₂Cu₃O₇₋<em>_x</em> (YBCO) is extremely sensitive to the growth atmosphere and the heat-treatment temperature. However, according to the existing literature, to obtain YBCO with preferred a-axis orientation, a buffer layer needs to be prepared on the substrate. In this work, YBCO films were grown via pulsed laser deposition, and the influence of N₂ and O₂ deposition atmospheres on the growth orientation of the YBCO films was studied. It was found that high-quality YBCO films with preferred <em>c</em>-axis orientation can be grown in O₂ atmosphere, but it is difficult to grow <em>a</em>-axis-oriented YBCO films in O₂ atmosphere without using a buffer layer; however, YBCO films with a high degree of preferred <em>a</em>-axis orientation can be grown in N₂ atmosphere without using a buffer layer. Furthermore, an <em>a</em>/<em>c</em>-oriented homogeneous YBCO bilayer with <em>c</em>-axis orientation in the lower layer and <em>a</em>-axis orientation in the upper layer was prepared. X-ray diffraction and scanning transmission electron microscopy results show that the bilayer is epitaxial with a good <em>a</em>/<em>c</em> orientation, and the resistance–temperature curve shows the occurrence of two transitions at temperatures of 91 and 71 K. We believe that these temperatures correspond to the superconducting onset transition temperatures of YBCO in the <em>c</em>- and <em>a</em>-axis growth orientations, respectively. The superconducting current usually flows within the Cu–O plane. With its sudden change in the direction of the current at the interface, the homogeneous junction prepared in this work is expected to provide new ideas for the research of high-temperature superconducting junction devices.</p></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"623 ","pages":"Article 1354551"},"PeriodicalIF":1.3,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141444645","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":"Effect of laser energy density on microstructure and critical current of YGBCO and HGBCO films fabricated by PLD","authors":"Xiang Wu","doi":"10.1016/j.physc.2024.1354547","DOIUrl":"10.1016/j.physc.2024.1354547","url":null,"abstract":"<div><p>Y_0.5Gd_0.5Ba₂Cu₃O_7-σ (YGBCO) and Ho_0.5Gd_0.5Ba₂Cu₃O_7-σ (HGBCO) targets with similar densities were prepared by solid-phase reaction. Pulsed laser deposition (PLD) technology was used to fabricate superconducting films with these targets. During the experiments in this paper, we varied the laser energy by adjusting the optical lens. The structure and texture of RE_0.5Gd_0.5Ba₂Cu₃O_7-σ (REGBCO, where RE = <em>Y</em>, Ho) thin films were analyzed by X-ray diffraction (XRD). The surface morphology was observed by atomic force microscopy (AFM) and scanning electron microscopy (SEM), and the superconducting critical current was measured at 77 K using the standard four-probe method. The laser energy density and different doping elements can affect the properties of REGBCO films. This may be related to the ejection process of target particles and the size of rare earth atoms. Additionally, we prepared a 510-meter long second-generation high-temperature superconducting tape with the optimized parameters. The critical current of the tape is 350 A, and the current density is 3.9 × 10⁶ A/cm².</p></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"623 ","pages":"Article 1354547"},"PeriodicalIF":1.7,"publicationDate":"2024-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141395620","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":"Gradient magnetic field measurement using first-order gradiometers equipped with 50 mm diameter pickup coils made out of a 2G high-Tc superconducting tape","authors":"Kazunori Komori ,&nbsp;Shunichi Arisawa ,&nbsp;Minoru Tachiki ,&nbsp;Shuuichi Ooi ,&nbsp;Tadayuki Hayashi ,&nbsp;Kazuhiro Endo","doi":"10.1016/j.physc.2024.1354519","DOIUrl":"https://doi.org/10.1016/j.physc.2024.1354519","url":null,"abstract":"<div><p>Two types of first-order gradiometers equipped with 50 mm diameter pickup coils were made out of an REBaCuO High-<em>T</em>_c superconducting (HTS) flexible tape. The HTS tapes were formed into the HTS gradiometers by ``cut-and-wind'' method without cable jointing.</p><p>The HTS gradiometers were examined at 77 K for magnetic sensitivity to a gradient field applied by an external coil. The axial-type HTS gradiometer eliminated the magnetic field output of the device induced by a uniform field, and enhanced the magnetic field output induced by a gradient field on the axis of the pickup coil. The planar-type HTS gradiometer made it possible to detect a 20 mm diameter steel cylinder placed beside the pickup coil in a uniform field of 100 µT by detecting the spatial field gradient in the vicinity of a ferromagnetic object.</p></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"622 ","pages":"Article 1354519"},"PeriodicalIF":1.7,"publicationDate":"2024-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141243184","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":"Development of high superconductor fraction (Ba, K)Fe2As2 wires with improved uniformity by two-axial rolling","authors":"Hao Xiong ,&nbsp;Chao Yao ,&nbsp;Wenwen Guo ,&nbsp;Peng Yang ,&nbsp;Zhihong Ren ,&nbsp;Dongliang Wang ,&nbsp;Xianping Zhang ,&nbsp;Yanwei Ma","doi":"10.1016/j.physc.2024.1354520","DOIUrl":"https://doi.org/10.1016/j.physc.2024.1354520","url":null,"abstract":"<div><p>Iron-based superconductors are regarded as prospective candidates for high magnetic field applications since they have very high upper critical field and low anisotropy. For practical applications, it is important to develop superconducting wires with strong current carrying capability. In this work, Cu/Ag composite sheathed (Ba, K)Fe₂As₂ (Ba-122) iron-based superconducting wires were fabricated by a two-axial rolling deformation process and a subsequent hot isostatic pressing (HIP) heat treatment. Compared with the previously reported Cu/Ag/Ba-122 wires prepared by groove rolling, the two-axial rolling allowed to use much thinner Cu/Ag composite sheath for wire fabrication, thus greatly increasing the filling factor of superconducting materials by about 5 times to 24 %, and lowering the volume fraction of silver down to 16 % in wires. By a comparative study on the microstructure and superconducting properties between the wires made by two-axial rolling and groove rolling processes, it is found that besides the significantly increased engineering critical current density, the former also exhibits improved homogeneity of mass distribution and uniformity of Ba-122/Ag interfaces, resulting in significantly enhanced <em>n</em>-values over 40 in magnetic fields up to 14 T. Our work suggests that two-axial rolling, combined with HIP processes, presents a promising approach to prepare iron-based superconducting wires with high filling factor, high uniformity and low cost for practical applications.</p></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"622 ","pages":"Article 1354520"},"PeriodicalIF":1.7,"publicationDate":"2024-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141243183","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}