Synthesis and properties of BiScO₃–PbTiO₃ powders and thin films using metal-organic precursor solutions

Abstract

The BiScO₃–PbTiO₃ binary system is known to have a morphotropic phase boundary (MPB) and a higher Curie temperature than Pb(Zr,Ti)O₃ and to exhibit excellent dielectric and ferroelectric properties. Perovskite BiScO₃–PbTiO₃ powders and thin films were synthesized via a chemical process using metal-organic precursor solutions. Homogeneous and stable precursor solutions, perovskite BiScO₃–PbTiO₃ single-phase powders and thin films on Pt/TiO_x/SiO₂/Si substrates were successfully prepared by optimizing the processing conditions. The 0.35BiScO₃–0.65PbTiO₃ composition was close to the MPB and had a Curie temperature of around 470°C. The electrical properties of BiScO₃–PbTiO₃ thin films showed a maximum at this composition. The dielectric permittivity of the 0.35BiScO₃–0.65PbTiO₃ thin film at the MPB was approximately 1700, with a dielectric loss tangent of less than 5% at room temperature. Furthermore, BiScO₃–PbTiO₃ thin films showed a typical ferroelectric polarization (P)–electric field (E) hysteresis loop. The remnant polarization (P_r) and coercive field (E_c) of the 0.35BiScO₃–0.65PbTiO₃ film were approximately 23 µC/cm² and 70 kV/cm, respectively.