Correlation between distribution of outgrowths and microwave surface resistance for YBa2Cu3O7 thin films

Abstract
A model was proposed to describe the effects of surface outgrowths on the microwave surface resistance of high Tc superconducting thin films. Calculated with experimental data the microwave surface resistance at 10 GHz for c‐axis oriented YBa2Cu3O7 thin films with no outgrowths could be as low as 70 and 4 μΩ at 77 and 4.2 K, respectively. The effect of the orientation of the surface outgrowths on the microwave loss has been discussed.