Influence of isovalent and aliovalent substitutions at Ti site on bismuth sodium titanate-based compositions on piezoelectric properties

The effect of isovalent and aliovalent substitutions in Bi0.5Na0.485La0.005TiO3 (BNLT) compounds were studied within the additive ranges of 0–2.5 at%. The Zr4+, Nb5+ and Fe3+ ions were selected as the substituents. The modified BNLT compounds were prepared by conventionally mixed-oxide method. The calcination and sintering were performed at the temperatures of 750–850 °C and 1050–1150 °C, respectively. An increase in the substituents contents affected the physical and piezoelectric properties. The BNLT compositions with the addition of 1 at% Zr4+, Nb5+ and Fe3+ ions exhibited high relative permittivities (ɛr) at 730, 735 and 660, respectively. The modified-BNLT with an addition of 1.0 at% Fe provided a piezoelectric coefficient (d33) of 155 pC/N, Curie temperature (Tc) of 320 °C and electromechanical coupling factors in planar (kp) and thickness (kt) modes of 15 and 45%, respectively.