Growth rate effects on thin Bi2Sr2CaCu2O8+δ textured rods

Cylindrical polycrystalline textured Bi-2212 samples of lengths up to 10 cm and 1 mm of diameter have been grown using a Laser Float Zone (LFZ) melting technique. In order to improve their transport critical current density (J(c)) at 77 K, the influence of growth rate on their microstructure has been analysed. The final transport properties of the textured materials are determined by the balance between better grain alignment and larger grain size, that takes place at the lowest growth rates, and the simultaneous appearance of cracks. The potential of LFZ grown BSCCO rods for the development of current leads at low fields is suggested. Optimum transport properties correspond to thin rods obtained using intermediate growth rates of 15 to 30 mm/h, with J(c)(77 K) values up to 5500 A/cm(2) in the self field. These also exhibit minimum resistivity values above T-c and irreversibility lines shifted towards higher temperatures and fields. (C) 1998 Elsevier Science B.V. All rights reserved.