Fast Growth Processes of Buffer Layers for YBCO Coated Conductors on Biaxially-Textured Ni Tapes

Epitaxial growth of CeO2 buffer layers on biaxially textured (001) Ni tapes was studied using reel-to-reel pulsed laser deposition. Relationship between microstructure and deposition parameters was systematically studied in order to develop reliable long tape coating processes. Prior to buffer layer deposition, Ni tapes were in situ annealed in forming gas (97% argon + 3% hydrogen) under various pressures and tape speeds to accelerate reel-to-reel annealing processes. It was found that orientation and texture of CeO2 buffer layers were sensitive to deposition parameters. X-ray diffraction analyses showed that CeO2 buffer layers had pure (001) orientation at forming gas pressure of 5 mTorr and 700 degrees C. Under optimized deposition conditions, highly (001) oriented CeO2 buffer layers have been achieved at a high tape speed of 20-50 m/h. In-lane texture of CeO2 buffer layers was 7 degree which was comparable to the value of Ni tapes.