Distribution of local critical current along sample length and its relation to overall current in a long Bi2223/Ag superconducting composite tape

Abstract

The distribution of the local critical current and the n-value along the sample length and its relation to the overall critical current were studied experimentally and analytically for the bent multifilamentary Bi2223/Ag/Ag-Mg alloy superconducting composite tape. Then, based on the results, it was attempted to simulate on a computer the dependence of the critical current on the sample length. The main results are summarized as follows. The experimentally observed relation of the distributed local critical current and n-value to the overall critical current was described comprehensively with a simple voltage summation model, in which the sample was regarded as a one-dimensional series circuit. The sample length dependence of the critical current was reproduced on the computer by a Monte Carlo simulation incorporating the voltage summation model and the regression analysis results for the local critical current distribution and the relation of the n-value to the critical current.

Simulation on the relation of distribution of overall critical transport current to that of local one in bent-damaged Bi2223 superconducting composite tape

“…͑8͒. In our former works, 23,24 it has been demonstrated that the measured overall I c and n-value are described well by substituting the measured sets of ͕I c ͑i͒, n͑i͖͒ of the local elements into Eq. ͑8͒.…”

“…͑2͒ below͔. 23,24,32 This function has been also used to describe the critical current distribution at weak links for analysis of V-I curve under no applied strain. 35,36 On the other hand, when the applied strain is high or the damage amount is large, it has been shown that the critical current distribution can be described by the bimodal Weibull distribution function ͓given by Eq.…”

“…1- 26 Also it has been known that the critical current is different from position to position in a specimen and from specimen to specimen. [19][20][21][22][23][24][25][26][27][28][29][30][31][32] Accordingly, when many specimens are tested, the local and overall critical currents are distributed, especially under the applied strain ͑Ͼ the irreversible strain͒ due to the inhomogeneous damage evolution. [19][20][21][22][23][24][25][26] It is needed to reveal the statistical features of the local and overall critical transport current distributions and the relation of overall critical current distribution to local one especially under various applied strains, which are important items for reliability and safe design.…”

Effects of Size of the Largest Crack and Size Difference among Cracks on Critical Current of Superconducting Tape with Multiple Cracks in Superconducting Layer

“…Cracking of the superconducting layer/filament occurs heterogeneously, due to which the I c -and n-values differ from specimen to specimen 612) and vary along the specimen length. 712,14,15) The same situation takes place under the existence of the heterogeneously distributed I c -reducing defects, introduced during the tape-fabrication process. 22,23) It is required to have full knowledge of the relation of heterogeneously distributed defects/cracks to superconducting property for safety design.…”

Surface morphology and physical properties of partially melt textured Mn doped Bi-2223

“…Another fact that the relation between the suppression of the superconducting transition temperature (Tc) and the local magnetic moment of impurities has generated a great deal of interest in the oxide superconductors. [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] From the early days, doping/substitution was one of the most important tools for identifying the nature of the pairing state and microscopic properties. A classical experimental study of the role of magnetic impurities in conventional superconductors was carried out 24 and followed by many in details.…”