Weakly coupled grain model for the residual surface resistance of YBa₂Cu₃O_x thin films

In the weakly coupled grain model which has been proposed to explain the residual surface resistance in high-7c superconducting polycrystalline thin films, the superconducting polycrystalline thin film is described as a network of superconducting grains coupled via Josephson junctions. In order to evaluate this model we have fabricated the coplanar waveguide resonator using c-axis oriented YBa₂Cu₃O_x thin films and measured the residual surface resistance. The experimental results are in good agreement with theoretical prediction.