HG-BASED SUPERCONDUCTING FILMS PREPARED BY SPRAY-PYROLYSIS TECHNIQUE

Hg-Ba-Ca-Cu-O films have been prepared on silver substrates using spray pyrolysis technique, following a two step procedure; first Ba-Ca-Cu-O films were prepared at a 350 degrees C substrate temperature and annealed at 780 degrees C for 6 hours to obtain a Ba-Ca-Cu-O precursor. Secondly, Hg-Ba-Ca-Cu-O films were prepared by spraying HgCl2 on a Ba-Ca-Cu-O precursor at a 250 degrees C substrate temperature. These films were then oxidized at 250 degrees C for 10 hours in an oxygen atmosphere. Films thus obtained were characterized by studying their microphotography, X-ray diffraction pattern and electrical properties. These films show superconductivity below 87 K.