High critical current density thick MOD-derived YBCO films

Abstract

High critical current density thick MOD (metal-organic-deposition)-derived Ba/sub 2/YCu/sub 3/O/sub 7-x/ (BYC) films have been prepared on latticed matched single crystal lanthanum aluminate substrates. Critical current densities of approximately one million amps per square centimeter (at 77 K) have been obtained from one micron thick BYC films. These superconducting films were prepared from a single MOD coating. Substrate coatings of a mixed metal trifluoroacetate precursor were first converted into high quality mixed metal oxyfluoride films by heat treating under controlled conditions. These films were then patterned and subsequently converted into epitaxial BYC by exposure to water vapor at higher temperatures, High critical current density films were obtained by controlling the conversion kinetics of the mixed metal oxyfluoride films into BYC.