Microwave properties of double-sided YBa/sub 2/Cu/sub 3/O/sub 7- delta / thin films deposited by metalorganic chemical vapor deposition

High-quality thin films of YBa/sub 2/Cu/sub 3/O/sub 7- delta / have been deposited by metalorganic chemical vapor deposition on both sides of 15-mm*15-mm <100> LaAlO/sub 3/ substrates without requiring the use of heat-sinking compounds. Typical transport data exhibited T/sub c/´s >87 K, transition widths <1 K, and J/sub c/´s >10/sup 6/ A/cm/sup 2/ (measured inductively at 77 K, 0 T). Microwave surface resistance measurements (36.4 GHz) at temperatures between 20 K and 100 K, made using a copper-cavity end-wall-replacement technique, showed a sharp drop through the transition temperature and yielded values at 77 K that were better than a 20* improvement over copper metal when scaled to 10 GHz. Double-sided coatings have been obtained by sequentially depositing each side of the substrate. Contamination of the backside during growth of the first-side film and of the first-side film during growth of the second-side film has been avoided by coating the susceptor with gold.<>