Current-voltage characteristics and transport current distributions in Ag/Bi-2223 monocore tapes

Ramsbottom, H. D.; Ito, Hiroshi; Horita, Takashi; Osamura, Kōzō

doi:10.1016/s0964-1807(98)00020-9

Cited by 3 publications

(2 citation statements)

References 25 publications

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“…For this class of problems, the Weibull distribution [35] has been proposed for the detection of weak points in high-temperature superconductor tapes [36]. A three-parameter Weibull distribution of the local pinning force or of the critical current has been utilized in interpretation of experimental current-voltage dependences of high-temperature superconductor wires [37][38][39], and has been widely used to investigate the effect of mechanical stress [26-28, 40, 41]. Here, we prefer to use the two-parameter Weibull distribution, with the cumulative probability:…”

Section: Statistical Analysis and Evaluation Of The Overall Critical ...mentioning

confidence: 99%

Analysis of critical current fluctuations as a means of checking the quality of high-temperature superconductor tape slitting

Gömöry

Šouc

Godar

et al. 2023

Supercond. Sci. Technol.

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The patterns of longitudinal Ic fluctuations in the 12 mm wide production HTS tapes are compared with those obtained after slitting them to the widths of 6 mm, 4 mm and 3 mm, respectively. In the statistical analysis of Ic(x) data, the overall critical current, Ic,ovrl, was first calculated. In case of fluctuating critical current, Ic,ovr is lower than the average of critical current, Ic,aver. Also, the dissipation concentrates in the “weak spots” with reduced critical current. Simple model allows to estimate the thermal runaway current, Itr, at which the weakest location would convert to a “hot spot” with rapid increase of temperature. In the prediction of Itr, essential is the absolute minimum of Ic value, Icmin. Then, by comparing the Icmin/Ic,aver ratio in the slit tapes to that established previously for the manufactured tape, one can deduce if some new defects have been introduced during slitting. Interesting is also to check if the relation of Itr vs. Ic,ovrl remained without changing, because the lower of these two quantities represents the limit of transportable current. We have found a reduction of both Icmin/Ic,aver and Itr /Ic,ovrl ratios in some tapes, containing the edges of the original 12 mm production tape. Contrary to our expectations, the most serious drops in slit tapes were not in the same location as in the original tape. However, systematically better performance of the central strips (the tapes with both edges cut) is a strong indication that the most serious defects are created already during manufacturing, close to the tape edges. We conclude that the tape cutting by femtosecond laser has not introduced an additional non-uniformity. The analysis also shows that the criticality of defects in applications is largely governed by the width of said defect, the cooling conditions and the thickness of the stabilizing layer.

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Section: Statistical Analysis and Evaluation Of The Overall Critical ...mentioning

confidence: 99%

Analysis of critical current fluctuations as a means of checking the quality of high-temperature superconductor tape slitting

Gömöry

Šouc

Godar

et al. 2023

Supercond. Sci. Technol.

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“…narrow distribution, small σ w ). Here the n value, which expresses the sharpness of voltage generation in the vicinity of the critical current, is related to the width of distribution [33]-a narrow distribution results in a large n value.…”

Section: Improvement Of Transport Properties In Practical Superconduc...mentioning

confidence: 99%

The Weibull distribution function as projection of two-dimensional critical current distribution in Ag/Bi₂Sr₂Ca₂Cu₃O_10+δtapes

Ogawa

Osamura²

2007

Supercond. Sci. Technol.

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Based on a two-dimensional numerical model, the origin of the shape of the Weibull distribution function (WDF) obtained from I–V analyses of Ag/Bi2223 tapes is investigated. In this work the correlation between the WDF and the two-dimensional local distribution of critical current f(I) is calculated by changing the shape of f(I). Since the WDF represents a one-dimensional critical current distribution, it can be interpreted as a kind of one-dimensional projection of f(I). It is revealed that two parameters of WDF (minimum critical current and scale parameter) inherit the properties of f(I) and that the third parameter (shape factor) is only correlated with system parameters such as volume fraction. Furthermore, the conditions required from the two-dimensional distribution necessary for good transport properties are identified.

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Influence of microscopic inhomogeneity on macroscopic transport current of Ag/Bi2223 tapes

Ogawa¹,

Osamura²

2004

Physica C: Superconductivity

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Current-voltage characteristics and transport current distributions in Ag/Bi-2223 monocore tapes

Cited by 3 publications

References 25 publications

Analysis of critical current fluctuations as a means of checking the quality of high-temperature superconductor tape slitting

Analysis of critical current fluctuations as a means of checking the quality of high-temperature superconductor tape slitting

The Weibull distribution function as projection of two-dimensional critical current distribution in Ag/Bi₂Sr₂Ca₂Cu₃O_10+δtapes

Influence of microscopic inhomogeneity on macroscopic transport current of Ag/Bi2223 tapes

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Current-voltage characteristics and transport current distributions in Ag/Bi-2223 monocore tapes

Cited by 3 publications

References 25 publications

Analysis of critical current fluctuations as a means of checking the quality of high-temperature superconductor tape slitting

Analysis of critical current fluctuations as a means of checking the quality of high-temperature superconductor tape slitting

The Weibull distribution function as projection of two-dimensional critical current distribution in Ag/Bi2Sr2Ca2Cu3O10+δtapes

Influence of microscopic inhomogeneity on macroscopic transport current of Ag/Bi2223 tapes

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The Weibull distribution function as projection of two-dimensional critical current distribution in Ag/Bi₂Sr₂Ca₂Cu₃O_10+δtapes