Polar Order Evolutions near the Rhombohedral to Pseudocubic and Tetragonal to Pseudocubic Phase Boundaries of the BiFeO(3)-BaTiO(3) System

Solid solutions of (1-x)BiFeO(3)-xBaTiO(3) (BF-BT, 0.05 ≤ x ≤ 0.98) were prepared and characterized. It was found that the dielectric constant ε(m), remnant polarization P(r) and piezoelectric coefficient d(33) reach their maximum values near the rhombohedral–pseudocubic phase boundary. In particular, the 0.7BF-0.3BT composition shows large polarization (P(r) > 20 μC/cm(2)) and a temperature-stable piezoelectric property (d(33) > 100 pC/N when the annealing temperature is lower than ~400 °C). Near the tetragonal–pseudocubic phase boundary, ε(m) and P(r) decrease, and the piezoelectric property vanishes when the BF content reaches 4 mol %.