LONG LENGTHS OF BI(2223) SUPERCONDUCTING TAPES

The optimization of the fabrication of mono-and multifilamentary Bi(22 23) tapes has been carried out in order to improve their transport pro perties on long lengths. At present, critical current densities as hig h as 34.5 and 28 kA cm(-2) have been reproducibly achieved at the liqu id nitrogen temperature on long mono-and multifilamentary tapes, respe ctively. The behaviour in magnetic field of the transport properties o f these tapes has been studied. At 77 K, a field of 1 T applied along the ab-planes of the Bi(2223) grains reduces the critical current by a factor of five and three in mono-and multifilamentary samples, respec tively. It has been found that the excellent behaviour of the transpor t properties of multifilamentary tapes in applied field is a direct co nsequence of the higher degree of texture of the Bi(2223) grains. (C) 1997 Published by Elsevier Science Ltd.