Effect of finite thickness on the surface impedance of high T/sub c/ thin films

The effect of the finite film thickness on the microwave surface impedance was investigated theoretically and experimentally. It was found that the surface resistance is enhanced due to the altered current density distribution in the film as well as power transmission through the film. The surface resistance of an YBa/sub 2/Cu/sub 3/O/sub 7- delta / thin films grown epitaxially on LaAlO/sub 3/ by laser ablation has been determined from data measured at 87 GHz by the closed-cavity method. At T=77 K, an effective surface resistance of (30+or-8) m Omega was measured, resulting in a corresponding value in the limit of infinite film thickness of (15+or-8) m Omega .<>