Incorporation of hyperfine probes into the thin-film superconductor YBa2Cu3O7−δ during deposition

Abstract
Radioactive 111In has been incorporated into oriented thin films of YBa2Cu3O7−δ during a thermal coevaporation process. The hyperfine technique of perturbed γγ‐angular correlation spectroscopy shows that 60% of the indium substitutes at a single site in the superconductor. We obtain spectra with reasonable statistics from 2 mCi of starting material, about 1% of which is incorporated into the film. Other methods of incorporating indium into films and bulk YBa2Cu3O7−δ have often resulted in a significant amount of indium being incorporated into impurity phases.