Role of rubidium cation substitution in the A-site of sodium bismuth titanate ceramics

Effect of large ionic radius cation rubidium (Rb) substitution in the A-site of sodium bismuth titanate (Bi0.5Na0.5−xRbx) TiO3 ceramics is studied. Influence of substitution on intrinsic and extrinsic contribution and impact on ferroelectric properties and piezoelectric constant are investigated. Small rhombohedral lattice distortion (δr) and minimum homogeneous strain (δ) are the primary intrinsic parameters which favors the extrinsic parameters such as domain wall motion and mobility of non-180° domain switching. Enhanced mobility softens the coercive field and increases remnant polarization to maximum. Reduced lattice distortion, low strain and enhanced mobility are the significant factors for enhanced piezoelectric constant, highest remnant polarization and decreased coercive field in (Bi0.5Na0.5−xRbx) TiO3 ceramics.