Degradation behavior in the remnant polarization of SrBi2Ta2O9 thin films by hydrogen annealing and its recovery by postannealing

Abstract

The degradation behavior in the remnant polarization (Pr) of sol–gel-derived SrBi2Ta2O9 (SBT) thin films, with Pt top and bottom electrodes, by annealing under a 5% H2/95% N2 atmosphere is investigated. The hydrogen annealing is performed at temperatures ranging from 250 to 480 °C. By annealing, the Pr drops to almost zero for all temperatures. Postannealing at temperatures higher than 700 °C under an air atmosphere recovers the Pr. Interestingly, the recovery is most ineffective for the sample annealed at the Curie temperature of the SBT films. A phenomenological model that explains this anomalous recovery behavior is presented.