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Characterizing Transport Current Defects in 1-cm-Wide YBa2Cu3O7-δ Coated Conductors

Published online by Cambridge University Press:  18 March 2011

G. W. Brown
Affiliation:
Structure/Property Relations (MST-8)
M. E. Hawley
Affiliation:
Structure/Property Relations (MST-8)
E. J. Peterson
Affiliation:
Superconductivity Technology Center (MST-STC) Materials Science & Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545
J. Y. Coulter
Affiliation:
Superconductivity Technology Center (MST-STC) Materials Science & Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545
P. C. Dowden
Affiliation:
Superconductivity Technology Center (MST-STC) Materials Science & Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545
P. N. Arendt
Affiliation:
Superconductivity Technology Center (MST-STC) Materials Science & Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545
S. R. Foltyn
Affiliation:
Superconductivity Technology Center (MST-STC) Materials Science & Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545
F. M. Mueller
Affiliation:
Superconductivity Technology Center (MST-STC) Materials Science & Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545
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Abstract

We have used a low temperature magnetic imaging system to determine current pathways in 5 cm long “good” and “bad” regions of a 1-cm-wide YBa2Cu3O7-δ coated conductor. The good and bad regions were identified with 4 point probe measurements taken at 1 cm intervals along the tape length. The current density map from the good region showed the expected edge peaked structure, similar to that seen in previous work on high quality test samples grown on single crystal substrates. The structure was also consistent with theoretical understanding of thin film superconductors where demagnetizing effects are strong. The maps from the bad region showed that the current was primarily confined to the right half of the sample. The left half carried only a small current that reached saturation quickly. Effectively halving the sample width quantitatively explains the critical current measured in that section. Spatially resolved x-ray analysis with 1 mm resolution was used to further characterize the bad section and suggested an abnormally large amount of a-axis YBCO present. This may be the result of non-uniform heating leading to a low deposition temperature in that area.

Type
Research Article
Copyright
Copyright © Materials Research Society 2002

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References

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