Structural and electrical properties of multiferroic (1−x)BiFeO3−xBi0.5K0.5TiO3 ceramics

The multiferroic (1−x)BiFeO3−xBi0.5K0.5TiO3 (BFO-xBKT) ceramic was prepared to investigate the dependence of its structural and electrical properties on BKT component. The ceramic processes a rhombohedral phase at 0 ≤ x ≤ 0.3 and a tetragonal phase at 0.5 ≤ x ≤ 1.0 while it owns the coexistence of these two phases at x∼0.4, according to the XRD patterns and the corresponding simulation with the Reitveld method. Specifically, BFO-0.4BKT shows a saturated polarization of 65.8 μC/cm2 and an enhanced piezoelectric d33 of 61 pC/N at room temperature which are much larger than those of other ceramics at x = 0-0.7. The dependence of dielectric constant on temperature suggests a strong relaxor characteristic and a high Curie temperature of ∼462 °C. Furthermore, the poled BFO-0.4BKT ceramic shows radial dielectric resonances at 20-300 °C due to the piezoelectric effect.