Preparation of YBCO films on CeO2-buffered MgO substrates by coating pyrolysis

Epitaxial CeO2 (35 nm) buffer layers were deposited on MgO(0 0 1) single crystal substrates by an electron beam gun for preparation of YBCO films by coating pyrolysis (CP). When the substrate temperature was higher than 660 deg. C, the CeO2 layer exhibited complete (0 0 1) orientation as judged from the θ-2θ X-ray diffraction pattern. Atomic force microscopic observations demonstrated that the surface of the CeO2 layer was very smooth; the average surface roughness being as small as 1 nm. Subsequently, YBCO films were prepared by the CP process using a metal acetylacetonate-based solution on the CeO2-buffered MgO substrates. Both the YBCO film and CeO2 buffer layer showed high crystallinity and fourfold symmetry in XRD θ-2θ and phi-scans, respectively. An average inductive-Jc value was 0.2 MA/cm2 at 77 K