Nucleation band growth of YBa2Cu3Ox on SrTiO3 and CeO2 by a BaF2 postdeposition reaction process

The nucleation and growth of the c-axis-aligned YBa2Cu3Ox on SrTiO3 and CeO2, from precursor films, were studied by examining quenched and fully processed specimens using transmission electron microscopy techniques. The precursor films, a stoichiometric mixture of fine-grained Y, Cu, and BaF2, were deposited using physical vapor deposition methods. An Y-Ba oxy-fluoride formed from the precursor contributed to the nucleation of YBa2Cu3Ox, while a liquid layer between the unreacted precursor and the YBa2Cu3Ox layer played an important role in the growth of YBa2Cu3O. However, the process of nucleation of YBa2Cu3Ox on SrTiO3 and CeO2 were significantly different.