Observation of enhanced electrostrictive strain in (1-2x)Na0.5Bi0.5TiO3-xBaTiO3-xBiAlO3 lead-free ceramics

Abstract Herein, the author reports the observation of composition dependent piezoelectric and electrostrictive behaviour in lead free (1-2x)Na0.5Bi0.5TiO3-xBaTiO3-xBiAlO3: NBT-BT-BAO [x = 0.01, 0.03, 0.05, 0.07, 0.09] ceramics synthesized through standard solid state reaction route. X-ray diffraction analysis of the samples confirms existence of structural phase transition from monoclinic to pseudocubic with increase of BT and BAO concentration supported by Raman spectroscopic analysis. A flipping from piezoelectric (x≤ 0.03) to near-electrostrictive (x≥ 0.05) characteristics has been realized from strain vs electric field measurements. Especially, (1-2x)Na0.5Bi0.5TiO3-xBaTiO3-xBiAlO3: x = 0.05 showed an enhanced strain of 0.33 %, Smax/Emax of 425 pm/V and an electrostrictive co-efficient (Q33) of 0.034 m4C−2 could be attributed to the presence of MPB by the co-existence of monoclinic and pseudocubic phases. Further, minimal temperature dependence of the electrostrictive strain is inferred from temperature dependent polarization and strain measurements.