SUITABILITY OF METALORGANIC CHEMICAL-VAPOR DEPOSITION-DERIVED PRGAO3 FILMS AS BUFFER LAYERS FOR YBA2CU3O7-X PULSED-LASER DEPOSITION

Phase-pure thin films of the YBa2Cu3O7-x (YBCO) lattice matched and lo w loss tangent perovskite insulator PrGaO3 have been grown in situ on single-crystal (110) LaAlO3 substrates by metalorganic chemical vapor deposition (MOCVD). Films were grown at temperatures of 750-800-degree s-C using beta-diketonate precursors M(dpm)3 (M=Pr,Ga; dpm =dipivaloyl methanate). YBCO films were then grown on the MOCVD-derived PrGaO3 by pulsed laser deposition (PLD). Scanning electron microscopy reveals th at the PrGaO3 films have smooth, featureless surfaces. As assessed by x-ray diffraction, the PrGaO3 films grow epitaxially on LaAlO3 with a high degree of (001) and/or (110) plane orientation parallel to the su bstrate surface, and the subsequent YBCO films grow with a (001) orien tation. Rocking curve and phi-scan analyses reveal that the PrGaO3 and YBCO films grow epitaxially. Cross-sectional high resolution electron microscopy and transmission electron microscopic selected area diffra ction confirm that the PrGaO3 and YBCO layers grow epitaxially. YBCO f ilms grown by PLD on the MOCVD-derived PrGaO3 exhibit T(c) = 91 K and J(c) = 6 X 10(6) A/cm2 at 77 K in zero field.