A COMPARATIVE-STUDY OF THE SURFACE RESISTANCES AND MICROWAVE PENETRATION DEPTHS OF YBA2CU3O7-DELTA THIN-FILMS WITH VARIOUS THICKNESSES

YBa2Cu3O7-delta (YBCO) thin films with different thicknesses were prep ared and patterned into the forms of microstrip ring resonators with s ilver grounds, for which the microwave properties were studied at temp eratures above the liquid nitrogen temperature and at frequencies of 8 to 12 GHz. The effective surface resistances of the YBCO thin films w ere calculated using Wheeler's incremental induction rule, from which the intrinsic surface resistances were calculated with a consideration of the finite-thickness effect on the surface resistance. The effecti ve surface resistance of a YBCO film with larger thickness can be smal ler than that of a YBCO film with a smaller thickness, depending on th e ratio of the film thickness to the penetration depth.