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Iowa State University

Series

Metallurgy

1988

Articles 1 - 2 of 2

Full-Text Articles in Physics

An Electron Channeling Study Of Polycrystalline Yba2cu3o X, J. D. Verhoeven, E. D. Gibson, L. Scott Chumbley, R. William Mccallum, H. H. Baker Jul 1988

An Electron Channeling Study Of Polycrystalline Yba2cu3o X, J. D. Verhoeven, E. D. Gibson, L. Scott Chumbley, R. William Mccallum, H. H. Baker

Materials Science and Engineering Publications

An electron channeling study has been done on large grained YBa2Cu3O x samples. Selected area channeling patterns (SACP) were used to examine several dozen grains on electropolished surfaces and it was demonstrated that (a) the twin planes observed in polarized optical light microscopy lie parallel to {110} crystal planes, and (b) the long flat sides of high aspect ratio grains are formed by basal planes, and the shorter sides are formed by either (010), (100), or {110} planes. A majority of the large grains examined were found to contain subgrains, misaligned by 0.5°–1° and ...


Possible Twin-Boundary Effect Upon The Properties Of High-Tc Superconductors, M. M. Fang, Vladimir G. Kogan, Douglas K. Finnemore, J. R. Clem, L. Scott Chumbley, D. K. Farrell Feb 1988

Possible Twin-Boundary Effect Upon The Properties Of High-Tc Superconductors, M. M. Fang, Vladimir G. Kogan, Douglas K. Finnemore, J. R. Clem, L. Scott Chumbley, D. K. Farrell

Materials Science and Engineering Publications

We have studied the field at which superconductivity nucleates in grain-aligned samples of Y1Ba2Cu3O7-δ very close to the transition temperature Tc. For the field parallel to the c axis and for temperatures within 2 K of Tc, the nucleation field is found to vary as (1-T/Tc)1/2. The data suggest that superconductivity localized near twin boundaries may exist at temperatures close to Tc. .AE