Significant improvement in the surface smoothness of post-annealed Y-Ba-Cu-O thin films upon silver addition

Abstract
We report the effect of silver addition on the surface quality of rf‐sputtered Y‐Ba‐Cu‐O thin films. The Y‐Ba‐Cu‐O‐Ag films appear to have very smooth surfaces even if the post‐annealing step is employed. The surface roughness of our ex situ grown Y‐Ba‐Cu‐O‐Ag film, having a 10.3 wt. % of silver, is within ±1% of the film thickness, which is more than 10 times better than the value of a typical post‐annealed high‐temperature superconducting film without silver.