Enhanced piezoresponse and electric field induced relaxor-ferroelectric phase transition in NBT-0.06BT ceramic prepared from hydrothermally synthesized nanoparticles

Abstract 0.94Na 0.5 Bi 0.5 TiO 3 -0.06BaTiO 3 (NBT-0.06BT) nanoparticles were synthesized by hydrothermal method and subsequently used to prepare NBT-0.06BT ceramics. After poling at the electric field of 3.5 kV/mm, the piezoelectric coefficient (d 33 ) and electromechanical coupling factor (κ p ) reached 171 pC/N and 0.31, respectively. The NBT-0.06BT ceramics also exhibited a large remanent polarization of 46.10 μC/cm 2 and electric field induced strain of 0.243% at 8 kV/mm corresponding to normalized strain d 33 * =303 pm/V (S max /E max ). The effects of polarization on crystalline phase, microstructures, dielectric properties and domain structures were investigated to reveal the origin of enhanced piezoresponse and electric field induced strain in as-prepared NBT-0.06BT ceramics. It can be observed that the tetragonal phase in NBT-0.06BT ceramics was enhanced and polar nanoregions were transformed into tweed-like structures and some lamellar domains after E-field poling. The dielectric response of NBT-0.06BT ceramics also exhibited an electric-field-induced relaxor-to-ferroelectric phase transition.