Superconducting Oxyfluoride Films
Original Publication Date: 1989-Feb-01
Included in the Prior Art Database: 2005-Jan-27
High Tc superconductivity has been reported in bulk material with the approximate composition YBa2Cu3F2Oy, where y is about 6. Attempts to incorporate fluorine into these compounds by various methods of fluorination have not been very successful. This article provides a method of incorporating fluorine into thin films of these compounds and controllably removing excess fluorine over the stoichiometry required for good superconducting properties. Thin films were prepared by three-source electron beam evaporation using Cu and Y metals as sources of those elements and barium fluoride as the source of both Ba and F. The BaF2 was fired overnight at 900oC in air to outgas and sinter it. It was evaporated from a tungsten hearth liner.