Superconductivity最新文献

{"title":"Two-band superconductivity in intercalated rhombohedral ZrNCl","authors":"Zhenkai Xie ,&nbsp;Ziheng Sun ,&nbsp;Xinmin Wang ,&nbsp;Junying Shen ,&nbsp;Liyuan Zhang","doi":"10.1016/j.supcon.2025.100169","DOIUrl":"10.1016/j.supcon.2025.100169","url":null,"abstract":"<div><div>The multiband superconductor offers a unique venue for investigating the interplay between Cooper pairing and inter-band interactions. Here we report the emergence of two-band superconductivity in hybridized superlattice Na<span><math><msub><mrow></mrow><mrow><mi>0.1</mi></mrow></msub></math></span>(1,3-diaminopropane)<span><math><msub><mrow></mrow><mrow><mi>0.25</mi></mrow></msub></math></span> ZrNCl. The intercalation of organic molecules and Na ions into the interlayer modulates the electronic structure near the Fermi surface, and promotes the emergence of intrinsic superconductivity with onset transition temperature <span><math><mrow><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>=</mo><mn>15</mn></mrow></math></span> K. Systematical investigations of upper critical field <span><math><msub><mrow><mi>H</mi></mrow><mrow><mi>c2</mi></mrow></msub></math></span> reveals that temperature dependence of <span><math><msub><mrow><mi>H</mi></mrow><mrow><mi>c2</mi></mrow></msub></math></span> can be well-described by two-band theory, yielding the out-of-plane and in-plane <span><math><msub><mrow><mi>H</mi></mrow><mrow><mi>c2</mi></mrow></msub></math></span> values of 2.9 T and 11.5 T, respectively. Furthermore, analysis of the reversible magnetization data confirms the intrinsic two-band characteristics, which deviate significantly from the predictions of the single-band Ginzburg–Landau(GL)model. Meanwhile, the superconducting state exhibits a two-fold rotational symmetry under in-plane magnetic fields, contrasting with the three-fold symmetric ZrNCl lattice. Angle-dependent <span><math><msub><mrow><mi>H</mi></mrow><mrow><mi>c2</mi></mrow></msub></math></span> behavior aligns with the three-dimensional (3D) anisotropic GL model. These findings establish the intercalated rhombohedral ZrNCl as a compelling platform for exploring multiband superconductivity.</div></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"14 ","pages":"Article 100169"},"PeriodicalIF":5.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143878838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multiphysics multilayer modelling and simulation of HTS REBCO magnets carrying direct currents under AC magnetic fields","authors":"Xuezhi Luo ,&nbsp;Jun Ma ,&nbsp;Huaqian Xiao ,&nbsp;Zhixuan Zhang ,&nbsp;Chao Yuan","doi":"10.1016/j.supcon.2025.100157","DOIUrl":"10.1016/j.supcon.2025.100157","url":null,"abstract":"<div><div>High temperature superconducting homopolar inductor machine (HTS-HIM) is concerned and studied for electric aircraft because of its high power density, high efficiency, and high power-to-weight ratio. In an HTS-HIM, the high temperature superconducting magnets carrying DC currents under alternating background magnetic fields work as excitation magnets. Under extreme electromagnetic conditions, the voltage, loss, and temperature of the HTS magnets will increase because of the dynamic resistance effect. To predict the behaviors of the HTS magnet, it is necessary to analyze its electromagnetic-thermal characteristics by using a multiphysics model. This paper establishes a 2D axisymmetric multilayer multiphysics HTS magnet model based on the <strong><em>H</em></strong>-formulation. By using this multilayer multiphysics model, the electromagnetic-thermal characteristics of each turn can be analyzed. Meanwhile, this model can not only analyze the total loss and loss components of each layer under various operating conditions but also predict the temperature and quench behaviors of each part. The result shows that the loss components of the REBCO layer have distinct temperature dependence. When considering the thermal field effect, the magnetization loss of the REBCO layer reduces by 75% and the transport loss of the REBCO layer increases by 45% under high direct currents and high AC magnetic fields. Meanwhile, the temperature of the external turn is higher than the internal turn, and the external turn is at risk of quench in the operating process when the direct currents and AC magnetic fields are high. The multilayer multiphysics model is a powerful tool for designing, analyzing, and optimizing the HTS magnets in HTS-HIMs, and this multiphysics modelling technique can be utilized in modelling and simulating HTS REBCO magnets in various applications.</div></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"14 ","pages":"Article 100157"},"PeriodicalIF":5.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143696133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rutherford MgB2 cable with 20 μm twisted filaments inside the Nb/CuNi/CuZn sheath","authors":"P. Kováč ,&nbsp;J. Kováč ,&nbsp;D. Berek ,&nbsp;M. Rindfleisch ,&nbsp;M. Búran ,&nbsp;T. Melišek ,&nbsp;I. Hušek ,&nbsp;M. Tomsic","doi":"10.1016/j.supcon.2025.100172","DOIUrl":"10.1016/j.supcon.2025.100172","url":null,"abstract":"<div><div>A fine-filamentary CuZn sheathed MgB ₂ wires produced by Hyper Tech Inc were used for 12 strand Rutherford cable of thickness 0.70–0.76 mm. Critical currents of short cable samples were measured at 4.2 K and external fields 4.0–8.0 T and also at temperatures 15–25 K and magnetic fields 1.0– 5.5 T. The threshold of engineering current density <span><math><mrow><msub><mrow><mi>J</mi></mrow><mrow><mi>e</mi></mrow></msub><mo>=</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>4</mn></mrow></msup></mrow></math></span> Acm ⁻² for the cable size of 0.72 mm <span><math><mo>×</mo></math></span> 2.55 mm was obtained at field of 4.5 T and temperature 4.2 K and at 2.3 T for 20 K, respectively. Magnetization measurements of the cable with transposed strands and twisted <span><math><mrow><mn>20</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span> filaments have shown reduced AC losses, but, the coupling currents loss contribution was still visible. AC losses measured for the same size Rutherford cable made of single-core wires demonstrate the effect of well decoupled filaments. Consequently, the cabling of thin single-core MgB ₂ wires shows a promising way for low loss conductors suitable for AC applications.</div></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"14 ","pages":"Article 100172"},"PeriodicalIF":5.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144263087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microwave surface resistance in MgB2: Effect of Te and cubic-BN addition on flux flow and pinning","authors":"Andrea Alimenti ,&nbsp;Enrico Silva ,&nbsp;Kostiantyn Torokhtii ,&nbsp;Pablo Vidal García ,&nbsp;Petre Badica ,&nbsp;Adrian Crisan ,&nbsp;Mihai Alexandru Grigoroscuta ,&nbsp;Nicola Pompeo","doi":"10.1016/j.supcon.2025.100170","DOIUrl":"10.1016/j.supcon.2025.100170","url":null,"abstract":"<div><div>MgB<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> is a perspective superconductor for many power applications. How this potential refers also to microwave or radiofrequency applications is still to be determined. Although its ultimate surface resistance in zero field is not competitive with conventional metallic superconductors, its strong pinning properties can favor RF applications in a dc magnetic field. Nonetheless, the RF response in the vortex state has been relatively less studied, as well as the effect of artificial pinning centers on the microwave surface resistance in the mixed state. In this paper we study the surface resistance of spark-plasma-sintered MgB<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, with and without Te and cubic-BN (cBN) addition, in a dc magnetic field up to 1.2 T. We summarize previous results on pure MgB<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, and we present new data on Te- and cBN- added MgB<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>. We use a two-tone dielectric-loaded resonator to measure the field-dependent surface resistance at 16.5 and 26.7 GHz in the temperature range from 10 K to <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span>. By exploiting the simultaneous measurements at two frequencies, we extract the flux-flow resistivity, the pinning constant <span><math><msub><mrow><mi>k</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span> and the depinning frequency <span><math><msub><mrow><mi>f</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span>. The two-band nature of MgB<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> affects the field dependence of the flux-flow resistivity. The microscopic superconducting state is not affected by the addition of artificial pinning centers, indicating that Te and cBN do not affect interband or intraband scattering. Pinning shows a measurable trend towards an increase in the Te- and cBN- added samples at higher temperatures and fields. We finally compare the results to those obtained in bulk Nb<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>Sn, also in view of possible in-field RF applications such as microwave cavity-based haloscopes.</div></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"14 ","pages":"Article 100170"},"PeriodicalIF":5.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stress accommodation in nanoscale dolan bridges designed for superconducting qubits","authors":"S. Skinner-Ramos ,&nbsp;M.L. Freeman ,&nbsp;D. Pete ,&nbsp;R.M. Lewis ,&nbsp;M. Eichenfield ,&nbsp;C. Thomas Harris","doi":"10.1016/j.supcon.2025.100158","DOIUrl":"10.1016/j.supcon.2025.100158","url":null,"abstract":"<div><div>Josephson junctions are the principal circuit element in numerous superconducting quantum information devices and can be readily integrated into large-scale electronics. However, device integration at the wafer scale necessarily depends on having a reliable, high-fidelity, and high-yield fabrication method for creating Josephson junctions. When creating Al/AlO<span><math><msub><mrow></mrow><mrow><mi>x</mi></mrow></msub></math></span> based superconducting qubits, the standard Josephson junction fabrication method relies on a sub-micron suspended resist bridge, known as a Dolan bridge, which tends to be particularly fragile and can often times fracture during the resist development process, ultimately resulting in device failure. In this work, we demonstrate a unique Josephson junction lithography mask design that incorporates stress-relief channels. Our simulation results show that the addition of stress-relief channels reduces the lateral stress in the Dolan bridge by more than 70% for all the bridge geometries investigated. In practice, our novel mask design significantly increased the survivability of the bridge during device processing, resulting in 100% yield for over 100 Josephson junctions fabricated.</div></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"14 ","pages":"Article 100158"},"PeriodicalIF":5.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143828769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advanced intelligent quench diagnostics for high temperature superconducting coils based on principal component analysis of voltage harmonic ratios and Support Vector Machine","authors":"Yahao Wu,&nbsp;Wenjuan Song,&nbsp;Mohammad Yazdani-Asrami","doi":"10.1016/j.supcon.2025.100173","DOIUrl":"10.1016/j.supcon.2025.100173","url":null,"abstract":"<div><div>The utilization of superconductors in modern aviation, power and energy, space, healthcare, and quantum sectors offers substantial advantages, including significant energy savings, higher reliability, lower CO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> emissions, higher efficiencies, and increased power densities. However, the quench phenomenon – transition from superconducting state to normal state – presents a major challenge, particularly in high temperature superconductors (HTSs), and especially in sensitive applications including fusion energy and aviation sectors. Most of the existing quench detection systems, i.e., conventional techniques, simply work based on threshold, and therefore, they have challenges being inflexible, non-intelligent, slow, and with the potential of missing quench or raising false alarm. This study proposes an advanced quench diagnostic technique aiming at enhancing reliability of HTS devices. This diagnostic technique quantifies quench events by analyzing the ratio of a selected harmonic component’s amplitude, including the second to ninth harmonics, to that of the fundamental frequency in voltage measurement. Fast Fourier Transform (FFT) is employed to analyze the frequency-domain characteristics of voltage signals in both quench and non-quench stages. Amplitudes of the main harmonic frequencies were measured in the spectrum and calculated the harmonic amplitude ratio. Principal Component Analysis (PCA) was applied to reduce dimensionality and extract the most relevant features associated with quench events. The original 17 harmonic ratio features were transformed into three principal components per label, preserving essential information of the dataset for classification. The Support Vector Machine (SVM) was used as an automatic intelligent decision-making technique to discriminate new cases of quench from non-quench condition. Finally, after continuous optimization of the PCA and SVM model, this novel approach, based on experimental data, demonstrated to reach an accuracy of 100% and promised a fast, more flexible, and reliable method for quench diagnostics. In addition, to validate and demonstrate the generalizability of the proposed quench detection method, this diagnostic technique was tested for a totally new HTS coil sample with different type, configuration, and turns number, which high discrimination accuracy was observed. This is a real testimony to the effectiveness of the proposed technique which is robust and generalized. However, further tests on larger and more diverse datasets are underway to accelerate its future applicability in fusion, electric transportation, and renewable energy sectors.</div></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"14 ","pages":"Article 100173"},"PeriodicalIF":5.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144229664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Finite element approach for calculating stress distribution in non-circular high-temperature superconducting coils","authors":"Zhihua Li ,&nbsp;Li Lu ,&nbsp;Zhuoyan Zhong ,&nbsp;Wei Wu","doi":"10.1016/j.supcon.2025.100168","DOIUrl":"10.1016/j.supcon.2025.100168","url":null,"abstract":"<div><div>Complex stress distribution arises in high-temperature superconducting (HTS) coil based on REBCO coated conductors, which is affected by the applied winding tension, thermal stress during cooling down, and electromagnetic forces when energizing the coil. The material and structure of bobbin and overband also play an important role.</div><div>In this study, a finite element (FE) method model was proposed for analyzing the stress of HTS coils with non-circular geometries, especially the stresses arise from winding tension and overband. Compared to traditional analytical methods, this approach is not only applicable to circular coils but also to coils of other shapes, such as racetrack and D-shape coils that could hardly be calculated analytically. Comparison between the traditional analytical model and the proposed FE method model was obtained, which validated the latter one according to the simulation results on the radial and hoop stresses of two circular coils. Next, the proposed approach was used to analyze the stress distribution of a racetrack coil and a D-shaped coil. Furthermore, a comprehensive analysis of the stress distributions in the epoxy impregnated racetrack coil and the D-shaped coil was conducted, considering winding stress, thermal stress, electromagnetic stress, and the influence of overband. Finally, we calculated the winding stress in the racetrack coil considering nonlinear compressive behaviors. The results show that the stress distributions are quite different from the case that not considering compressibility.</div></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"14 ","pages":"Article 100168"},"PeriodicalIF":5.6,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143878837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An adaptive-extended modeling to accelerate electromagnetic study and data generation in superconducting magnet applications","authors":"Mingyang Wang ,&nbsp;Haolan Chen ,&nbsp;Tiantian Cai ,&nbsp;Fangliang Dong ,&nbsp;Junjie Jiang ,&nbsp;Jie Sheng ,&nbsp;Zhuyong Li","doi":"10.1016/j.supcon.2025.100156","DOIUrl":"10.1016/j.supcon.2025.100156","url":null,"abstract":"<div><div>Superconducting magnets possess unique electromagnetic properties, making them applicable in fields such as nuclear magnetic resonance, maglev, and fusion. These applications generally involve diverse environments featuring AC or DC conditions, where superconducting properties are influenced by various factors. Specifically, the most concerning properties in high temperature superconducting (HTS) magnets include critical current, AC loss, screening current effects, and so on. Finite element method is widely used in reliable numerical studies for these properties. Several popular models have been proposed and developed to get higher precision and less calculation time. However, constrained by computational resources, they still have challenges in supporting high-throughput analysis. In various studies on electromagnetic characteristics of magnets, a substantial amount of data is often required to facilitate the introduction of artificial intelligence (AI) methods or optimization approaches. This paper proposes an adaptive-extended J-model to compute superconducting properties, further enhancing the efficiency of electromagnetic study and also serving to generate dataset for AI methods. It reduces computation time to only 20%–30% of that of the existing fastest model while maintaining similar levels of accuracy. By using this method as a data-generative tool, the dataset of a series of HTS solenoids including 2000 turns is expeditiously obtained and employed to predict the screening current induced field. The predictive performance is reliable under the dataset calculation time of mere minutes. This study significantly shortens the time to realize big dataset demands, accelerating electromagnetic study of superconducting magnets in various scenarios.</div></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"13 ","pages":"Article 100156"},"PeriodicalIF":5.6,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143629389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corrigendum to previously published articles","authors":"","doi":"10.1016/j.supcon.2025.100150","DOIUrl":"10.1016/j.supcon.2025.100150","url":null,"abstract":"","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"13 ","pages":"Article 100150"},"PeriodicalIF":5.6,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heavy ion irradiation effects on the high-frequency properties of YBCO and Nb3Sn thin films","authors":"Gianluca Ghigo ,&nbsp;Michela Fracasso ,&nbsp;Roberto Gerbaldo ,&nbsp;Daniele Torsello ,&nbsp;Dorothea Fonnesu ,&nbsp;Matteo Fretto ,&nbsp;Cristian Pira ,&nbsp;Natascia De Leo ,&nbsp;Laura Gozzelino","doi":"10.1016/j.supcon.2024.100149","DOIUrl":"10.1016/j.supcon.2024.100149","url":null,"abstract":"<div><div>High-energy heavy-ion irradiation is known to produce effective vortex pinning centers in the high-<span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> cuprate superconductors, as amorphous columnar tracks. However, while the beneficial effects on pinning has been well established through dc and low-frequency characterizations, the same analysis in the high-frequency regime is far from complete. Even less investigated are the effects of heavy ion irradiation on the microwave properties of metallic low-<span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> superconducting films. Here, we report on the effects of 1.15 GeV Pb irradiation on the high frequency properties of YBa<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Cu<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>O<span><math><msub><mrow></mrow><mrow><mn>7</mn><mo>−</mo><mi>x</mi></mrow></msub></math></span> (YBCO) and Nb<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>Sn thin films. The microwave analysis, performed in the range 7-8 GHz, allows obtaining the fundamental properties of both the materials, as the London penetration depth and gap values, and of the main pinning parameters, through the determination of the Campbell length by measurements in dc magnetic fields up to 4 T. GeV heavy-ion irradiation confirmed to be extremely effective for YBCO also in the high frequency regime, enhancing both the pinning constant and the depinning frequency, thus pushing the critical current density to about 30% of the depairing current density. On the other hand, the discontinuous but correlated defects produced in Nb<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>Sn was found to be ineffective to enhance the pinning properties (the pinning constant in fact decreases), while the observed increment of the depinning frequency is ascribed to the reduction of the vortex viscosity, in turn due to the growth of the normal state resistivity.</div></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"13 ","pages":"Article 100149"},"PeriodicalIF":5.6,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}