Intrinsic flux pinning mechanisms in different thickness MgB2 films

Yang, Can; Ni, Zhimao; Guo, Xin; Hu, Hai-Quan; Wang, Yinxi; Zhang, Y.; Feng, Qian; Gan, Zizhao

doi:10.1063/1.4979075

Cited by 7 publications

(4 citation statements)

References 43 publications

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“…As the field increases, figure 10(b) shows that the decrease in J c is nearly the same for temperatures 5-10 K and becomes more pronounced as the temperature goes up. At 20 K, the J c is 2.3 × 10 5 A cm −2 at 1 T and 8.5 × 10 4 A cm −2 at 2 T, comparable to our previous values on epitaxial MgB 2 thin films [68] and higher than the values on polycrystalline MgB 2 planar films on Nb substrate [33]. From the J c (H) shown in figure 10(b), the flux-pinning force F p = µ 0 HJ c may be extracted.…”

Section: Superconducting Transitionsupporting

confidence: 90%

“…Near zero applied field, it is shown that the J c is in the range 1.2 − 2.6 × 10 6 A cm −2 at temperatures 5-25 K, with the value 1.7 × 10 6 A cm −2 at 5 K-10 K lower than 2.6 × 10 6 A cm −2 at 15 K because of the suppression from flux jumps at 5-10 K as exemplified in the inset of figure 10(a) [52]. We note that these J c values are lower than the superior values of above 10 7 A cm −2 for high-quality epitaxial MgB 2 thin films [36,67], but comparable to both typical values for epitaxial MgB 2 films [68] and that reported on high-quality polycrystalline MgB 2 planar films [33,36,69]. According to previous simulations [18,19,26], these values of J c would be promising for potential applications in ICF.…”

Section: Superconducting Transitionsupporting

confidence: 52%

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Properties of superconducting MgB₂ spherical shells deposited on 2 mm and 1 mm diameter Si₃N₄ spheres

Xu¹,

Sun²,

Zhao³

et al. 2023

Supercond. Sci. Technol.

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Superconducting spherical shells may not only provide an appealing platform for exploring superconductivity in three-dimensional (3D) geometries with curved surfaces, but also be practically applied in important fields, such as in gyroscopes and gravimeters. In inertial confinement fusion (ICF), the perturbation on the target capsule caused by traditional contact support methods is recognized as one of the major contributors to performance degradation in ICF implosions. It was proposed recently that coating the capsule with a thin superconducting MgB2 spherical shell to realize non-contact support by means of magnetic levitation at the required temperatures ∼ 20 K might offer a promising solution to this longstanding problem. To simulate the coating of ICF capsules, we deposited MgB2 spherical shells onto polycrystalline Si3N4 spheres (diameter d = 2 mm and 1 mm) via a hybrid physical–chemical vapour deposition technique. For both diameters, the spherical shells, of about 1 µm in thickness and covering the whole spheres completely, were polycrystalline with thin plate-shaped MgB2 crystallites oriented randomly and closely connected. The spherical shells exhibited superconducting transition at a zero resistance temperature T c z e r o of 38.5–39.4 K in four-probe resistance measurements and ideal diamagnetism at low temperatures in magnetization measurements, suggesting the good crystallinity and homogeneity of the shells. The upper critical field H c 2 , the irreversibility field H i r r and the lower critical field H c 1 were characterized and showed similar magnitudes and temperature dependencies for the d = 2 mm and 1 mm shells, yielding H i r r of 7–8 T and H c 1 of 7–12 mT at 20 K. The superconducting critical current density J c values, evaluated from the magnetization hysteresis loops, were 1.8 × 10 6 A cm−2 and 8.5 × 10 4 A cm−2 at 20 K under zero and 2 T applied field, respectively, for the d = 1 mm shell. The occurrence of small flux jumps was observed at low temperatures up to 12 K and in low fields below 0.3 T. The results demonstrate the feasibility of fabricating MgB2 spherical shells with properties applicable to potential areas employing magnetic levitation such as in ICF and that MgB2 spherical shells may be exploited as an experimental system to study superconductivity in 3D curvilinear geometry.

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Section: Superconducting Transitionsupporting

confidence: 90%

Section: Superconducting Transitionsupporting

confidence: 52%

Properties of superconducting MgB₂ spherical shells deposited on 2 mm and 1 mm diameter Si₃N₄ spheres

Xu¹,

Sun²,

Zhao³

et al. 2023

Supercond. Sci. Technol.

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show abstract

“…The pinning force density → F p (B, T) in pure and doped MgB 2 films is studied in detail [40][41][42]. Here, we chose for the analysis the → F p (B, J c , T) dataset reported by Zheng et al [23], who fabricated high-quality MgB 2 films by hybrid physical-chemical vapor deposition on two types of silicon carbide single-crystal substrates (4H-SiC and 6H-SiC) and reported transport J c (B, T) datasets for the film deposited on a 6H-SiC substrate.…”

Section: Mgbmentioning

confidence: 99%

New Scaling Laws for Pinning Force Density in Superconductors

Talantsev

2022

Condensed Matter

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Since the report by Fietz and Webb (Phys. Rev.1968, 178, 657–667), who considered the pinning force density, Fp→=Jc→×B→ (where Jc is the critical current density and B is applied magnetic flux density), in isotropic superconductors as a unique function of reduced magnetic field, BBc2 (where Bc2 is the upper critical field), Fp→ has been scaled based on the BBc2 ratio, for which there is a widely used Kramer–Dew–Hughes scaling law of Fp→B=Fp,maxBBc2p1−BBc2q, where Fp,max, Bc2, p, and q are free-fitting parameters. To describe Fp→B in high-temperature superconductors, the Kramer–Dew–Hughes scaling law has been modified by (a) an assumption of the angular dependence of all parameters and (b) by the replacement of the upper critical field, Bc2, by the irreversibility field, Birr. Here, we note that Fp→ is also a function of critical current density, and thus, the Fp→Jc scaling law should exist. In an attempt to reveal this law, we considered the full Fp→B,Jc function and reported that there are three distinctive characteristic ranges of BBc2,JcJcsf (where Jcsf is the self-field critical current density) on which Fp→B,Jc can be splatted. Several new scaling laws for Fp→Jc were proposed and applied to MgB2, NdFeAs(O,F), REBCO, (La,Y)H10, and YH6. The proposed scaling laws describe the in-field performance of superconductors at low and moderate magnetic fields, and thus, the primary niche for these laws is superconducting wires and tapes for cables, fault current limiters, and transformers.

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“…The pinning force scaling changes from grain boundary pinning to point pinning on increasing preparation temperature and finally the sharp, low-field peak in volume pinning force (𝐹 𝑝 ) disappears. The pinning behaviors of four different thicknesses for MgB2 thin films have been discussed by Yang and co-workers [14]. These films were prepared by a hybrid physical-chemical vapor deposition technique.…”

Section: Introductionmentioning

confidence: 99%

Computational Study of Field-Dependent Pinning Force for Pure MgB2 Superconductor

Ansari

Rao

2022

Preprint

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The logarithmic exponential regression model is proposed for the pure MgB2 superconductor in this study. The predicted values of normalized pinning force as a function of the reduced field are evaluated and compared to the measured values at a wide range of temperatures. The proposed model well described the best-suited model for the estimated predicted values. The predicted values of the reduced field dependence of normalized pinning force are in good agreement with the measured values for the pure MgB2 superconductor. Some statistical error estimations namely mean bias error, mean absolute bias error and root mean square error is calculated at different temperatures from 10−30K. The large value of the coefficient of regression, R2 confirms the effectiveness and significance of the proposed model. The proposed model is applicable in this study to find the accurate and precise values of the computational data.

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Intrinsic flux pinning mechanisms in different thickness MgB2 films

Cited by 7 publications

References 43 publications

Properties of superconducting MgB₂ spherical shells deposited on 2 mm and 1 mm diameter Si₃N₄ spheres

Properties of superconducting MgB₂ spherical shells deposited on 2 mm and 1 mm diameter Si₃N₄ spheres

New Scaling Laws for Pinning Force Density in Superconductors

Computational Study of Field-Dependent Pinning Force for Pure MgB2 Superconductor

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Intrinsic flux pinning mechanisms in different thickness MgB2 films

Cited by 7 publications

References 43 publications

Properties of superconducting MgB2 spherical shells deposited on 2 mm and 1 mm diameter Si3N4 spheres

Properties of superconducting MgB2 spherical shells deposited on 2 mm and 1 mm diameter Si3N4 spheres

New Scaling Laws for Pinning Force Density in Superconductors

Computational Study of Field-Dependent Pinning Force for Pure MgB2 Superconductor

Contact Info

Product

Resources

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Properties of superconducting MgB₂ spherical shells deposited on 2 mm and 1 mm diameter Si₃N₄ spheres

Properties of superconducting MgB₂ spherical shells deposited on 2 mm and 1 mm diameter Si₃N₄ spheres