J. Phys. IV France 11 (2001) Pr11-157-Pr11-161
Preparation of TI-1223 and TI-2223 superconducting films by spray pyrolysisS. Phok1, Z.I. Supardi2, A. Sin2, Ph. Galez1, J.L. Jorda1 and F. Weiss2
1 LAIMAN, Université de Savoie, ESIA, BP. 806, 74016 Annecy cedex, France
2 Laboratoire des Matériaux et du Génie Physique, INPG-CNRS, BP. 46, 80402 Saint-Martin-d'Hères cedex, France
Starting from nitrate solutions, precursors with composition Ba:Ca:Cu = 2:2:3 have been sprayed on MgO and LaAlO3 single crystal substrates to form homogeneously distributed multiphase layers with a grain size smaller than 1 µm. Based on the knowledge of the Tl-Ba-Ca-Cu-O system, ex-situ thallination leading to TlBa2Ca2Cu3O2 (Tl-1223) and Tl2Ba2Ca2Cu3O2 (Tl-2223) films, 1 to 2 µm in thickness, has been performed. SEM images reveal plate-like grains, 20 µm or more along the large dimension, and X-Ray diffraction experiments show that the films have both a c-axis and an in-plane texture more pronounced on LaAlO3 than on MgO. The critical temperatures for Tl-1223 and Tl-2223 films are 113 K and 120 K, respectively, with transition width of about 2 K. The critical current densities Jc (77 K, 0 T), deduced from screening method, is above 7x105 A/cm2. The optimisation of the parameters conditioning the film fabrication and the properties are under work.
© EDP Sciences 2001