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Y2BaCuO5 Addition and Its Effects on Critical Currents in Large grains of YBa2Cu3O7-σ: A Quantitative Microstructural Study

Published online by Cambridge University Press:  10 February 2011

Manoj Chopra
Affiliation:
Henry Krumb School of Mines, Columbia University, N.Y. N.Y-10027
R. L. Meng
Affiliation:
fTexas Center of Superconducting Research, Houston. TX
C. W. Chu
Affiliation:
fTexas Center of Superconducting Research, Houston. TX
Siu-Wai Chan
Affiliation:
Henry Krumb School of Mines, Columbia University, N.Y. N.Y-10027
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Abstract

The addition of Y2BaCuO5 (211) particles to large grain Yba2Cu3O7−δ (Y123) has significantly improved the critical current (Jc) in this material. Here a systematic quantitative analysis on the effect of the measured 211 present in large grains of Y123 has been performed, after the process of melt texturing, both on a microscopic and a nanoscopic scale with a systematic variation of the initial volume percent of 211 addition. From the correlation between critical current measurements and quantitative microscopy of both (001) and (110) sections, a maximum value of weighted Jc is observed corresponding to a measured Y123 volume percent of 20%. Although an increasing addition of 211 is effective in producing efficient flux pinning sites in the Y123 matrix, percolation paths in the Y123 matrix become limited for supercurrent. Accounting for the loss of liquid phase, we estimate an optimum initial volume of 211 for highest Jc to be 40%. Further correlation between the Jc and the true flux pinning force (Fp) shows a maximum pinning force for an initial 211 addition of 40%. However the pinning efficiency of the superconducting Y123 matrix is found to improve with an increasing 211 addition. Hence an optimum amount of 211 addition is essential for obtaining the best possible electrical characteristics in the superconducting composite.

Type
Research Article
Copyright
Copyright © Materials Research Society 1996

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References

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