Effect of colony boundaries, defects and 2212 phase on J{sub c} of Ag-clad BSCCO tapes

Journal Article · Sun Jun 01 04:00:00 EDT 1997 · Advances in Cryogenic Engineering

OSTI ID:482072

Dou, S X; Wang, R K; Ionescu, M; Liu, H K ^[1]

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1. Univ. of Wollongong (Australia)

Studies on the interfaces and microstructural defects in the broad face and longitudinal cross-sectional specimens of Ag-sheathed Bi-based 2223 and 2212 tapes revealed that majority of twist boundaries are either low angle or near 90{degrees} boundaries and most colony boundaries are mixed type boundaries. 2212 tape has much better in-plane alignment than 2223 due to the melt-texture-growth nature in the former. A thin amorphous layer is commonly formed at colony boundaries with adjacent basal-planes on both sides of the boundary. Tilt boundaries are clean and the lattices from both sides of the boundary are well matched. A systematic study on the correlation between J{sub c} and 2212 fraction in numerous 2223 tapes shows that tapes with J{sub c} above 15,000 A/cm{sup 2} at 77K contain certain fraction of 2212 phase up to 10% while the tapes with undetectable low fraction of 2212 do not ensure a higher J{sub c}. These results seem to indicate that the predominant weak links in the tape are not residual 2212 layers at twist boundaries in 2223 tapes with a low 2212 fraction. The predominant weak links in tapes are colony boundaries and J{sub c} is assumed to be controlled by colony boundaries in low fields. The activation energies for flux motion in the Bi-2223 tapes are higher than those for the Bi-2212 tapes and 2212 single crystals which may be attributable to the difference in the dislocation density due to the different processing used for both materials.

• OSTI ID: 482072
• Report Number(s): CONF-950722--
• Journal Information: Advances in Cryogenic Engineering, Journal Name: Advances in Cryogenic Engineering Vol. 42B; ISSN 0065-2482; ISSN ACYEAC
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BISMUTH OXIDES
CALCIUM OXIDES
COPPER OXIDES
CRITICAL CURRENT
GRAIN BOUNDARIES
HIGH-TC SUPERCONDUCTORS
MICROSTRUCTURE
SILVER
STRONTIUM OXIDES
SUPERCONDUCTING WIRES