Effect of Colony Boundaries, Defects and 2212 Phase on Jc of Ag-Clad BSCCO Tapes
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° 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 Jc and 2212 fraction in numerous 2223 tapes shows that tapes with Jc above 15,000A/cm2 at 77K contain certain fraction of 2212 phase up to 10% while the tapes with undetetable low fraction of 2212 do not ensure a higher Jc. These results seam 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 Jc 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.
KeywordsCritical Current Density Amorphous Layer Twist Boundary Tilt Boundary Broad Face
Unable to display preview. Download preview PDF.
- 1.A. Umezawa, Y. Feng, H.S. Edelman, T.C. Willis, J.A. Parrell, D.C. Larbalestier, G.N. Riley and W.L. Carter, Physica C 219:378(1993).Google Scholar
- 2.Y. Feng and D.C. Larbalestier, Interface Sci. 1: 401(1994).Google Scholar
- 3.O. Eibl, M. Wilhelm, P. Kummeth and H.W. Nemuller, Proceedings of the 7th Inter. Workshop on Critical Currents in Superconductors, ed. by H.W. Weber, Alpbach, Austria (1994) pp27–34.Google Scholar
- 9.H.K. Liu, Y.C. Guo and S.X. Dou, Proceedings of the Beijing International Conference, High Temperature Superconductivity(BHTSC’92), ed by Z.Z. Gan, S.S. Xie and Z.X. Zhao, World Scientific, Singapore(1993), p343.Google Scholar
- 11.L.N. Bulaevskii, J.R Clem, L.L. Glazma and A.P. Malozemoff, Phys. Rev., B45:25545 (1992).Google Scholar
- 14.RRamesh, S.M. Green and G. Thomas, Study of High Temperature Superconductors, ed by A. Narliker, Nova Science Publisher, (1990), 5:361.Google Scholar
- 16.Jyh-Lih Wang, X.Y. Cai, R.J. Kelley, S.E. Babcock, D.C. Larbalestier and M.D. Vander, Physica C, (in press).Google Scholar
- 17.Y.H. Li, J.A. Kilner, M. Dhalle and A.D. Caplin, preprintGoogle Scholar
- 18.D.M. Kroager, A. Goyal and E.D. Specht, Controlled Processing of High-Temperature Superconductors: Fundamentals and Applications, International Workshop on Superconductivity co- Sponsored by ISTEC and MRS, Lune 18–21, 1995, Maui, Hawaii, USA, pp217.Google Scholar
- 19.H.K. Liu, S.X. Dou, M. Sumpton and E.W. Collings, Advances in Science & Technology (8), Superconductivity and Superconducting materials Technologies, ed. by P. Vincezini (1995) p110.Google Scholar
- 20.V.M. Pan, Study of High Temperature Superconductors, ed by A. Narlikar, Nova Science Publishers, New York (1990), 5:319.Google Scholar