In-plane aligned superconducting Tl0.78Bi0.22Sr1.6Ba0.4Ca2Cu3O9 films on rolling assisted biaxially textured substrates

In-plane aligned superconducting Tl0.78Bi0.22Sr1.6Ba0.4Ca2Cu3O9 ((Tl,Bi)-12 23) films on Rolling Assisted Biaxially Textured Substrates (RABiTS) with J (c) of 4.25 x 10(5) A/cm(2) at 77 K and zero-field have been synthesized by laser ablation and post-ablation annealing. The as-ablated films were amor phous due to the low substrate temperature during ablation. The amorphous f ilms were then wrapped together with an unfired Tl0.95Bi0.22Sr1.6Ba0.4Ca2Cu 3O9 pellet in silver foil. The whole package was finally annealed in a tube furnace at 780-810 degrees C for 40-60 min in flowing argon to crystallize the films. X-ray diffraction (XRD) shows that the annealed films consist o f mainly c-axis aligned (Tl,Bi)-1223 phase with a small amount of (Tl,Bi)-1 212 phase. The full width at half maximum (FWHM) values of XRD peaks show t hat both phases are epitaxial, with in-plane and out-of-plane alignments co mparable to those of the underlying Ni and buffer layers (CeO2 and YSZ). Fo ur-probe transport measurements showed superconducting transition temperatu res (T(c)s) of 105-109 K depending on the annealing conditions. With extern al magnetic field applied parallel to the c-axis, irreversibility magnetic fields reached beyond 3 T at 77 K and beyond 5 T at 64 K. (C) 1999 Publishe d by Elsevier Science B.V. All rights reserved.