High T/sub c/ superconducting Y-Ba-Cu-O oxide films by sputtering and molecular beam epitaxy: Morphology, structural characterization and superconducting properties

We have studied the morphology, structure and superconducting properties high T/sub c/ oxide films, mostly in the Y-Ba-Cu-O sytem, prepared by various sputtering techniques (diode and magnetron sputtering) and molecular beam epitaxy (MBE). In the as-deposited condition the chemical homogeneity both across the film and through the thickness is excellent as measured by Rutherford backscattering spectrometry (RBS). Post oxygen annealing at temperature above 800/sup 0/C yields the orthorhombic superconducting phase as revealed by the x-ray diffraction. High-quality epitaxially grown Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub 7-//sub x/ films deposited on single-crystal SrTiO/sub 3/ substrates with various orientations were obtained with a narrow rocking curve (<0.3/sup 0/) in the direction perpendicularly to the film plane. Also, for the first time we observed the electron channeling in this class of materials. Sharp superconducting resistive transitions with T/sub c/(R = 0) above 89K and critical current density at 77K have been reproducibly achieved.