SCANNING TUNNELING MICROSCOPY OF LASER-DEPOSITED YBCO THIN-FILMS

High-quality YBCO thin films deposited on yttria-stabilized zirconia substrates by laser ablation have been studied by scanning tunneling microscopy in air. The films have been grown at different substrate temperatures, and the measured critical current density (J(c)) and surface resistance (R(s)) have been shown to vary with deposition temperature; where the J(c) decreased with deposition temperature, the R(s) increased. These variations were related to a change in the film surface morphology, showing screw dislocations for the films with lower deposition temperature, while at higher temperatures these dislocations were absent.