Influence of BaTiO 3 content on the structure and properties of Na 0.5Bi 0.5TiO 3 crystals

Lead-free Na0.5Bi0.5TiO3-x%BaTiO3 single crystals of different compositions (x=0, 2, 4, 4.5 and 5.5) were grown using a top-seeded solution growth method. Temperature-dependent X-ray diffraction revealed the presence of a high-temperature tetragonal phase that existed over a narrow composition range of 04, rhombohedral domains were found that persisted on heating to only about T-c-150 degrees C. Investigations of the properties revealed a dramatic increase in the dielectric constant (upto 500%), a decrease in the coercive field (300%), and an increase in the longitudinal piezoelectric constant (1000%) with modest increases in x, as the high-temperature tetragonal ferroelastic phase was suppressed and as the morphotropic-phase boundary approached.