Reactive ion beam deposition of thin films in the bismuth-calcium-strontium-copper oxide ceramic superconductor system

Abstract
Reactive ion beam deposition has been used to grow c‐axis‐oriented superconducting thin films in the Bi‐Ca‐Sr‐Cu‐O (BCSCO) system around the cation ratio 1:1:1:1 on single‐crystal (001) MgO. The films show a single superconducting transition with an initial onset near 85 K and a critical current of 5×104 A/cm2 at 10 K. Two different BCSCO‐containing phases have been identified in the thin films: one with a tetragonal pseudo‐body‐centered subcell, c=24.4 Å, which is not superconducting above 28 K, and a second with c=30.6 Å, which is responsible for the superconductivity. Electron diffraction measurements on the 30.6 Å phase are consistent with those previously reported for the bulk ceramic.