Thin films of non-stoichiometric perovskites as potential oxygen sensors

Thin films of non-stoichiometric perovskites of general formula ABO\u2082.\u2085 + x have been grown, on sapphire substrates, by the technique of pulsed laser ablation/deposition. The structural properties of the films upon exposure to atmospheres of various oxygen pressures, at elevated temperatures, have been determined by X-ray diffraction; they show changes which correlate with those found for bulk powder samples. For the material SrFeO\u2082.\u2085 + x, with 0 64 x 64 0.5, pressure-composition isotherms reveal several pressure ranges over which structural changes occur. By monitoring the changes in physical properties that accompany the bulk chemical changes, this system can be exploited to provide a thin-film sensor, the structural changes of which are specific to oxygen.Peer reviewed: YesNRC publication: Ye