METALORGANIC CHEMICAL VAPOR-DEPOSITION OF LOW MICROWAVE SURFACE-RESISTANCE YBA2CU3O7 ON (100) LAALO3 AND (100) SRTIO3

Thin films of YBa2Cu3O7-delta on (100) LaAlO3 and (100) SrTiO3, up to 5000 angstrom thick, were grown by metalorganic chemical vapor deposition. The as-deposited films were c-axis oriented, and had transition temperatures between 87 and 89 K, transition widths less than or equal to 1 K, and critical current densities of 1-3X10(6) A/cm2 at 77 K. Microwave surface resistance measurements at 36 GHz on (100) LaAlO3 showed significant improvements over copper metal at 77 K. Films grown on (100) SrTiO3 exhibited slightly better properties than those grown on (100) LaAlO3. Films which were slightly deficient in barium and rich in yttrium consistently demonstrated superior properties.