Analysis of diffuse phase transition and relaxorlike behaviors in Pb_(0.5)Sr_(0.5)TiO_3 films through dc electric-field dependence of dielectric response

摘要

The pulsed-laser deposited Pb_(0.5)Sr_(0.5)TiO_3 (PST) films with typical diffuse phase transition (DPT) and relaxorlike characteristics have been investigated by dc electric-field dependence of dielectric response. It was found that the butterfly hysteresis still persists above the Curie temperature on the curves of dielectric constant changing with the dc electric field. This result was correlated with the existence of polar nanoregions (PNRs) in the PST films, as well established in terms of a multipolarization mechanism model. Consequently, the existence of PNRs may be one of the crucial causes of the DPT and relaxorlike behaviors in PST ferroelectric films.