Polar Order Evolutions near the Rhombohedral to Pseudocubic and Tetragonal to Pseudocubic Phase Boundaries of the BiFeO3-BaTiO3 System

Abstract

Solid solutions of (1-x)BiFeO3-xBaTiO3 (BF-BT, 0.05 ≤ x ≤ 0.98) were prepared and characterized. It was found that the dielectric constant εm, remnant polarization Pr and piezoelectric coefficient d33 reach their maximum values near the rhombohedral-pseudocubic phase boundary. In particular, the 0.7BF-0.3BT composition shows large polarization (Pr > 20 μC/cm2) and a temperature-stable piezoelectric property (d33 > 100 pC/N when the annealing temperature is lower than ~400 °C). Near the tetragonal-pseudocubic phase boundary, εm and Pr decrease, and the piezoelectric property vanishes when the BF content reaches 4 mol %.