Abstract
We have found that the Bi(2212) grains in unreacted Ag/Bi(2223) tapes at the end of the cold-rolling process show already a high degree of texture. X-ray diffraction analysis and current transport measurements at 77 K in magnetic fields up to 0.5 T have been performed before and after reaction on tapes with thicknesses in the range from 75 to 286 μm (filament thickness between 30 and 115 μm). The critical current density j c increases for smaller tape thicknesses, a maximum being found for a tape thickness of about 90 μm, below which sausaging effects are observed. The mean misalignment angles of Bi(2223) grains in these tapes have been determined by angle-dependent transport critical curent data at 77 K. We have found that the mamin reason for the enhancem,ent of j c for thin tapes in due to the higher average texture of the Bi(2223) grains when compared to thick tapes. This is a direct consequence of the high degree of texture of Bi(2212) grains after the cold-rolling process, which has been observed here on 90 μm thick tapes with j c(77 K, 0 T) reaching between 25 and 30 kA/cm 2.
Published Version
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