Dependence of Critical Current Density on Granular Arrangement in Ceramic Superconductors

ABSTRACTThe critical current density Jc of bulk ceramic superconductors is often several orders of magnitude lower than that of a single crystal or oriented fílm of the same material due to the weak links residing at the boundaries between single crystals within the ceramic sample. Assuming that the rate of electron transport within each single crystal is much faster than the average rate of electron transport between adjacent single crystals, a working hypothesis of Jc enhancement by granular reorientation is formulated which includes the“brickwall”model and melt-texturing as special cases with long-range granular alignment which usually leads to rigid and brittle bulk samples. Simple geometric considerations show that only short-range local granular alignment is necessary for high Jc. For mis reason, it should be possible to make flexible superconducting wires and tapes for commercial applications at or above 77K.

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Analysis of Electromagnetic Properties of Bulk Superconductors

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2021.19274 ◽

2021 ◽

Vol 21 (9) ◽

pp. 4941-4943

Author(s):

Sang Heon Lee

Keyword(s):

Critical Current Density ◽

Single Crystal ◽

Critical Current ◽

Current Density ◽

Magnetic Force ◽

Electromagnetic Properties ◽

Weak Links ◽

Metallic Silver ◽

Bulk Superconductor ◽

Slow Cooling

In the present study, a YBa2Cu3O7−y bulk superconductor added with 5~10 wt% Ag was fabricated employing Sm123 as a seed to produce a superconductive single crystal. Metallic silver was added to the single crystal of YBa2Cu3O7−y to remove defects such as cracks and pores. Electromagnetic properties of the bulk superconductor at 77 K were analyzed based on relationships of magnetic levitation, trapped magnetic force, and critical current density. The critical current density of the superconductor at 77 K and 0 T was 3.53 × 104 A/cm2. Discontinuous points in the distribution of magnetic field lines were not observed, implying that these two specimens grew well as a single crystal without specific weak links. For the growth of a superconductive nano crystal employing slow cooling at temperature of formation of 123 phase, superconductive nano crystals were aligned in a-b direction, the direction of peak current flow. The peak value of the trapped magnetic force of the YBa2Cu3O7−y superconductor specimen was 3.23 kG. Using the FC method, peak forces of attraction and repulsion were 21.696 N and 70.168 N, respectively.

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Critical Current Enhancement in Single-Crystal Ba2Ycu3O7

MRS Proceedings ◽

10.1557/proc-169-911 ◽

1989 ◽

Vol 169 ◽

Cited By ~ 4

Author(s):

R. B. van Dover ◽

E. M. Gyorgy ◽

L. F. Schneemeyer ◽

A. E. White ◽

S. Glarum ◽

...

Keyword(s):

Critical Current Density ◽

Single Crystal ◽

Fast Neutron ◽

Single Crystals ◽

Critical Current ◽

Neutron Irradiation ◽

Current Density ◽

Proton Irradiation ◽

Significant Enhancement ◽

Fast Neutron Irradiation

AbstractThe critical current density, Jc, of single crystals of Ba2YCu3O7 is comparable to that of melt-textured-growth materials as well as to the intragrain Jc of bulk polycrystalline Ba2YCu3O7. Typical values at 77 K and 9 kOe are near 5x 103 A/cm2, and are presumably limited by weak pinning. We have obtained a significant enhancement of this pinning-limited Jc by three techniques: 1) a short reannealing procedure, 2) fast neutron irradiation, and 3) proton irradiation. Interestingly, the combination of the first technique followed by either irradiation is not as effective as the iradiation alone. That is, the best candidates for irradiation are not necessarily those with the highest initial Jc.

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Large Enhancement of JC in YBacuo Single Crystals Induced by Proton Irradiation

MRS Proceedings ◽

10.1557/proc-169-915 ◽

1989 ◽

Vol 169 ◽

Author(s):

L. Civale ◽

A.D. Marwick ◽

M.W. Mcelfresh ◽

A.P. Malozemoff ◽

F. Holtzberg

Keyword(s):

Critical Current Density ◽

Single Crystal ◽

Single Crystals ◽

Critical Current ◽

Current Density ◽

Proton Irradiation ◽

Fold Increase ◽

Unirradiated Sample ◽

Maximum Value ◽

Large Enhancement

AbstractWe have used magnetization measurements to study the effect of proton irradiation on the critical current density of a YBaCuO single crystal. We have obtained a maximum value of 1.5x105 A/cm2 at 77 K and 1 T at a fluence of 2 x 1016 cm-2, representing a 50-fold increase with respect to the unirradiated sample.

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Influence of the carbon substitution on the critical current density and AC losses in MgB2 single crystals

The European Physical Journal B ◽

10.1140/epjb/e2010-10683-9 ◽

2010 ◽

Vol 78 (3) ◽

pp. 359-365 ◽

Cited By ~ 1

Author(s):

M. Ciszek ◽

K. Rogacki ◽

K. Oganisian ◽

N. D. Zhigadlo ◽

J. Karpinski

Keyword(s):

Critical Current Density ◽

Single Crystals ◽

Critical Current ◽

Current Density ◽

Ac Losses ◽

Carbon Substitution

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Microstructures and Enhancement of Critical Current Density in<tex>$rm YBa_2rm Cu_3rm O_7$</tex>Thin Films Grown by Pulsed Laser Deposition on Various Single Crystal Substrates Modified by Ag Nano-Dots

IEEE Transactions on Applied Superconductivity ◽

10.1109/tasc.2005.848731 ◽

2005 ◽

Vol 15 (2) ◽

pp. 3046-3049 ◽

Cited By ~ 10

Author(s):

A.H. Li ◽

M. Ionescu ◽

H.K. Liu ◽

T. Silver ◽

X.L. Wang ◽

...

Keyword(s):

Thin Films ◽

Critical Current Density ◽

Single Crystal ◽

Pulsed Laser Deposition ◽

Critical Current ◽

Current Density ◽

Pulsed Laser ◽

Laser Deposition

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Effect of ZnO Nano-Oxide Addition on the Superconducting Properties of the (Bi.Pb)2223 Phase

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.324.241 ◽

2011 ◽

Vol 324 ◽

pp. 241-244 ◽

Cited By ~ 6

Author(s):

R. Mawassi ◽

R. Awad ◽

Mohamad Roumie ◽

M. Kork ◽

I. Hassan

Keyword(s):

Critical Current Density ◽

Critical Current ◽

Current Density ◽

Flux Pinning ◽

High Temperature Superconductors ◽

Weak Links ◽

Superconducting Properties ◽

X Ray ◽

Weight Percentage ◽

Nano Oxide

The major limitation of Bi-system superconductor applications is the intergrain weak links and weak flux pinning capability producing low critical current density of the Bibased phases. In order to enhance these characteristics and other superconducting properties, effective flux pinning centers are introduced into high temperature superconductors. In this work, different weight percentages of ZnO nano oxide were introduced at the final stage of the Bi1.8Pb0.4Sr2Ca2Cu3O10-y superconductor preparation process. Phase characterization was completed by X-ray diffraction (XRD). Exact constitution of the samples was determined using particle induced X-ray emission (PIXE). Granular and microstructure were investigated using scanning electron microscopy (SEM). Electrical resistivity as function of the temperature was carried to evaluate the relative performance of samples, and finally, E-J characteristic curves were obtained at 77K. Using 0.4 ZnO weight percentage, the electrical and granular properties were greatly enhanced, indicating more efficient pinning mechanisms. A critical current density of 949 A/cm2 was obtained which represents more than twice the value obtained for the pure sample (Jc= 445 A/cm2).

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Anisotropic critical current density and flux pinning mechanism of Fe1+yTe0.6Se0.4 single crystals

Superconductor Science and Technology ◽

10.1088/1361-6668/ac3632 ◽

2021 ◽

Author(s):

Yongqiang Pan ◽

Nan Zhou ◽

Bencheng Lin ◽

Jinhua Wang ◽

Zengwei Zhu ◽

...

Keyword(s):

Critical Current Density ◽

Single Crystals ◽

Critical Current ◽

Current Density ◽

Flux Pinning ◽

Magnetic Hysteresis ◽

Magnetic Hysteresis Loop ◽

Pinning Force ◽

Magnetization Relaxation ◽

Pinning Mechanism

Abstract Fe1+yTe0.6Se0.4 has considerable application potential due to its large critical current density (J c) and high upper critical magnetic field (H c2). However, the uncertainty of the anisotropy of J c and the unclear flux-pinning mechanism have limited the application of this material. In this study, the J c in three directions were obtained from magnetic hysteresis loop measurements. A large anisotropy of J c ab /J c c ~ 10 was observed, and the origin of the anisotropy was discussed in details. Flux pinning force densities (F p) were obtained from J c, and a non-scaling behavior was found in the normalized pinning force f p[F p/F p-max] versus the normalized field h[H/H c2]. The peaks of pinning force shift from a high h to a low h with increasing temperature. Based on the vortex dynamics analysis, the peak shift was found to originate from the magnetization relaxation. The J c and F p at critical states free from the magnetic relaxation were regained. According to the Dew-Hughes model, the dominant pinning type in Fe1+yTe0.6Se0.4 clean single crystals was confirmed to be normal point pinning.

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