Dielectric, optical, piezoelectric and ferroelectric studies of NBT–BT ceramics near MPB

Solid solutions of the lead free (1−x)Na0.5Bi0.5TiO3–xBaTiO3/NBT–xBT (where x=0.05, 0.06, 0.07, and 0.08) ferroelectric ceramics were synthesized in single perovskite phase by solid state reaction route. Higher values of remnant polarization (Pr) ~31.71 μC/cm2, dielectric constant (εr) ~5067, piezoelectric coefficient (d33) ~105 pC/N, electromechanical coupling coefficient (kp) ~21.17 and maximum induced strain% of ~0.45 were obtained in the x=0.07 NBT–xBT composition. The bipolar fatigue behavior of the NBT–xBT (x=0.05, 0.06, 0.07, and 0.08) ceramics was carried out by the remnant polarization vs. number of cycles (up to 109) study. Optical band gap of all the NBT–xBT ceramics was found to be ~3 eV. Excellent dielectric, piezoelectric and ferroelectric properties suggested that the x=0.07 is the actual MPB composition of the NBT–xBT system.