Buffers for high temperature superconductor coatings. Low temperature growth of CeO sub(2) films by metal-organic chemical vapor deposition and their implementation as buffers

• Published in: Physica. C, Superconductivity Superconductivity, 1999-01, Vol.320 (3), p.154-160
• Main Authors: Wang, Anchuan, Belot, John A, Marks, Tobin J, Markworth, Paul R, Chang, Robert P H, Chudzik, Michael P, Kannewurf, Carl R
• Format: Article
• Language: English
• ISSN: 0921-4534

Smooth, epitaxial cerium dioxide thin films have been grown in-situ in the 450-650 degree C temperature range on (001) yttria-stabilized zirconia (YSZ) substrates by metal-organic chemical vapor deposition (MOCVD) using a new fluorine-free liquid Ce precursor. As assessed by X-ray diffraction, transmission electron microscopy (TEM), and high-resolution electron microscopy (HREM), the epitaxial films exhibit a columnar microstructure with atomically abrupt film-substrate interfaces and with only minor bending of the crystal plane parallel to the substrate surface near the interface and at the column boundaries. With fixed precursor temperature and gas flow rate, the CeO sub(2) growth rate decreases from approximately 10 angstroms/min at 450 degree C to approximately 6.5 angstroms/min at 540 degree C. The root-mean-square roughness of the films also decreases from 15.5 angstroms at 450 degree C to 4.3 angstroms at 540 degree C. High-quality, epitaxial YBa sub(2)C sub(3)O sub(7-x) films have been successfully deposited on these MOCVD-derived CeO sub(2) films grown at temperatures as low as 540 degree C. They exhibit T sub(c) identical with 86.5 K and J sub(c) identical with 1.08x10 super(6) A/cm super(2) at 77.4 K.