Degradation of Y 1Ba 2Cu 3O 7− x thin epitaxial films in aqueous medium and control of degradation using polymer overlayers deposited by pulsed excimer laser

Abstract

Superconducting thin films of Y 1Ba 2Cu 3O 7− x were deposited onto YZrO 2 substrates by pulsed excimer ( λ = 248 nm) laser ablation. The deposited films were exposed to the aqueous medium for different durations of time ranging from 15 min to 42 h. The degradation of Y 1Ba 2Cu 3O 7− x epitaxial films was studied by X-ray diffraction and measurements of the transition temperature T c. In a separate set of experiments, subsequent to deposition of superconducting films, thin layers (0.1-1μm) of polymer (polyacrylonitrile) were deposited onto the films without breaking vacuum. The sandwiches were subjected to the same aqueous treatment. It was observed that degradation effects were passified by the polymer overlayer.