Ferroelectric properties of Pr and Nb co-substituted Sr 0.8Bi 2.2Ta 2O 9 thin films

Thin film of both A- and B-site co-substituted Sr _0.8Bi _2.2Ta ₂O ₉ (SBT) by Pr ³⁺ and Nb ⁵⁺, i.e. Sr _0.8Pr _0.1Bi _2.1Ta _1.5Nb _0.5O ₉ (SPBTN) was fabricated on Pt/Ti/SiO ₂/Si substrates by metalorganic decomposition method. The Nb ⁵⁺ substitution at B-site and Pr ³⁺ substitution at A-site enhanced the remanent polarization and reduced the coercive field of the films, respectively. The remanent polarization (2 P_r) value of the SPBTN film was 22 μC/cm ². The coercive field (2 E_c) value of the SPBTN film was 102 kV/cm, which was much lower than that of SBTN (165 kV/cm). The effects of substitution on structural and ferroelectric properties of SBT were discussed in detail. As a result, the A- and B-sites co-substitution may be one of the promising ways to improve ferroelectric properties of SBT.