THE ROLE OF GAS-PHASE OXIDATION AND COMBINATION DURING LASER DEPOSITION OF YBA2CU3O7-X IN AMBIENT OXYGEN

Spectroscopic absorption and emission measurements have been used to s tudy laser deposition of YBCO films. They show that >95% of the monato mic Y and Ba initially ablated from the target undergo gas-phase chemi cal combination before film deposition. In contrast, considerable mona tomic Cu persists into the deposition region. in this region, equilibr ated gas temperatures are of the order of 2700 K. It is suggested that this high temperature facilitates film crystallization and epitaxial growth. The survival of monatomic Cu in the plume to the site of depos ition is a manifestation of its endothermic reaction with O-2.