Superconducting and Structural Properties of Sputtered Thin Films of YBa sub 2 Cu sub 3 O sub 7--x

Thin films of YBa sub 2 Cu sub 3 O sub x have been fabricated by dc triode sputtering from two metallic targets. Post-annealing in pure oxygen after sputtering resulted in superconducting films with a T sub c onset as high as 89K and a midpoint T sub c of 75K. Preliminary results are reported of films deposited on sapphire, MgO and sol--gel coatings of ZrO sub 2 on sapphire, with and without buffer layers of Ag. The chemical and physical structures of these films were analyzed by using several X-ray diffraction techniques and Rutherford backscattering spectroscopy. 10 ref.--AA