Bi - 2212 r Ag tapes melt - grown under an elevated magnetic field ž / 0 – 10 T

Bi-2212rAg tapes with a thickness of 30 mm were melt-grown in elevated magnetic fields following two different thermal sequences. The transport critical current density, J dependence on the maximum processing temperature, cooling c rate, holding time and magnetic field was studied systematically. The quantity of impurity phase was decreased by reducing the holding time above the melting point of Bi-2212 and optimizing the cooling rate in the partial-melt regime. Under these conditions, the overall degree of texture of the Bi-2212 tapes was increased. Application of a large magnetic field during melt-growth in the partial melt regime improved the amount of well textured Bi-2212 in the thick filaments, leading to Ž . 4 increased critical current density J . The highest J 4.2 K, self field obtained in this work was approximately 8.5=10 c c Arcm. It is demonstrated that a well textured structure and high J can be achieved in thick Bi-2212 filaments. q 1999 c Elsevier Science B.V. All rights reserved.