Organometallic chemical vapor deposition routes to high<i>T</i><sub><i>c</i></sub>superconducting Tl‐Ba‐Ca‐Cu‐O films
作者:Darrin S. Richeson、Lauren M. Tonge、Jing Zhao、Jiming Zhang、Henry O. Marcy、Tobin J. Marks、Bruce W. Wessels、Carl R. Kannewurf
DOI:10.1063/1.101515
日期:1989.5.22
Films of the Tl‐Ba‐Ca‐Cu‐O high Tc superconductor can be prepared by either of two organometallic chemical vapor deposition routes. Ba‐Ca‐Cu‐O films are first prepared on yttria‐stabilized zirconia using the volatile precursors Ba(heptafluorodimethyloctanedionate)2, Ca(dipivaloylmethanate)2, and Cu(acetylacetonate)2. Deposition is carried out at 5 Torr pressure with argon as the carrier gas and water
We observed the Josephson effect with hysteretic I-V characteristics on lateral-type grain boundary junctions using Y1Ba2Cu3O7-delta (YBCO) and Bi2Sr2Ca1Cu2O8+delta(BSCCO) films. In the case of YBCO, grain boundaries consisting of an a-axis oriented needle-like,main surrounded by c-axis oriented grains are used for Josephson junctions. The junctions using as-grown films without annealing did not show hysteretic I-V characteristics, but they show RSJ-type I-V characteristics with no hysteresis. after appropriate annealing in pure Ar, this junction property changes to have hysteretic I-V characteristics. In the case of BSCCO, grain boundaries consisting of a (110) oriented needle like grain surrounded by (001) oriented grains sire used. Hysteretic I-V characteristics are observed for the sample, indicating the presence of the intrinsic Josephson effect caused by stacked CuO2 double layers along the c-direction. (C) 1997 Elsevier Science B.V.