Title :
Distribution of the transport critical current in Ag-(Bi,Pb)/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub x/ reinforced tape-form conductors
Author :
Glowacki, B.A. ; Lo, W. ; Yuan, J. ; Jackiewicz, J. ; Liang, W.Y.
Author_Institution :
Cambridge Univ., UK
fDate :
3/1/1993 12:00:00 AM
Abstract :
The spatial distribution of the transport critical current, I/sub c/, in the reinforced-tape-form, silver-clad (Bi,Pb)/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub x/ conductor manufactured by cold multistep rolling has been established by the in-situ measurements as a function of the thickness of the ceramic core. The measurements show that current is almost uniformly distributed through the whole cross-section of the core in the wire, almost independently of the initial I/sub c/ value of the tape. The effect of densification, texturing, and surface diffusion on the formation of the intergrain connectivity along the a-b plane of the core, at the silver-ceramic interface, and in the core has been investigated and is discussed in detail. The I/sub c/ anisotropy measurements and a study of magnetically aligned and randomly oriented samples lead to a functional relationship between the crystallographic orientation, morphology and connectivity of the grains in the tape. The variation of the hole concentration near the grain boundary region of the 2223 phase has been investigated by transmission electron energy loss spectroscopy.<>
Keywords :
bismuth compounds; calcium compounds; composite superconductors; critical current density (superconductivity); crystal orientation; electron energy loss spectra; grain boundaries; high-temperature superconductors; lead compounds; silver; strontium compounds; superconductive tunnelling; surface diffusion; Ag-Bi/sub 2-x/Pb/sub x/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub x/; ceramic core; crystallographic orientation; densification; grain boundary; high temperature superconductivity; intergrain connectivity; morphology; multistep rolling; reinforced-tape; spatial distribution; surface diffusion; texturing; transmission electron energy loss; transport critical current; Ceramics; Conductors; Critical current; Current measurement; Magnetic cores; Manufacturing; Strontium; Surface morphology; Thickness measurement; Wire;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
