INFLUENCE OF EPITAXIAL-GROWTH ON SUPERCONDUCTING PROPERTIES OF LFZ BI-SR-CA-CU-O FIBERS .2. MAGNETIC-SUSCEPTIBILITY AND TRANSPORT-PROPERTIES

Magnetic susceptibility and critical current density of superconductin g fibres of the Bi-Sr-Ca-Cu-O system grown by laser floating zone (LFZ ) technique are strongly dependent on pulling rates. A favourable grai n orientation for current transport was obtained for the highest pulli ng rate, 4.17 x 10(-6) ms(-1). Fibres grown in this condition show the lowest fraction of superconducting phases but exhibit the highest val ues of J(c). Epitaxial growth of superconducting phases 2212 and 4413 on the primary phase to crystallize, Sr0.3Ca0.7CuO2 (1/1), leads to th e favourable alignment of the b-axis to the fibre axis. After heat tre atment this orientation remains in the new crystals of 2212 and 2223 p hases. (C) 1997 Elsevier Science B.V.