INSITU DEPOSITION OF SUPERCONDUCTING YBA2CU3O7-X AND DYBA2CU3O7-X THIN-FILMS BY ORGANOMETALLIC MOLECULAR-BEAM EPITAXY

Smooth, c-axis oriented, superconducting thin films of YBa2Cu3O7-x and DyBa2Cu3O7-x have been grown on (100) MgO by organometallie molecular-beam epitaxy. To our knowledge this is the first report of this technique for the fabrication of this class of high T(c) superconductors. Y (or Dy) beta-diketonate organometallic sources are utilized with Ba and Cu metallic sources. Films are grown in situ by codepositing from these sources in an ozone ambient with a substrate temperature of 700-degrees-C. The use of an active oxygen source (ozone) is required for decomposition of the organometallic sources as well as for the attainment of superconducting films in situ. The films are characterized by T(c)'s as high as 85 K and J(c)'s of 1.2 X 10(6) A/cm2 at 12 K and 2.4 X 10(3) A/cm2 at 77 K. In addition to the four point T(c) and J(c) results, alternating-current susceptibility measurements are also reported. The composition of the films has been determined by Rutherford backscattering spectroscopy, Auger and secondary ion mass spectroscopy analysis, with the smoothness of the films characterized by scanning tunneling microscopy.