Dielectric, Ferroelectric and Piezoelectric Properties of the Lead Free 0.9BaTiO₃-(0.1-x)Bi_0.5Na_0.5TiO₃-xBi(Mg_0.5Ti_0.5)O₃ Solid Solution

Abstract

Solid solution of 0.9BaTiO₃-(0.1-x)Bi_0.5Na_0.5TiO₃-xBi(Mg_0.5Ti_0.5)O₃ (BT-BNT-xBMT) system, where x = 0.00, 0.02, 0.04, 0.06, 0.08, 0.10, was synthesized by the solid state reaction. Dense BT-BNT-xBMT ceramics were obtained by sintering at 1,150–1,250˚C for 4 h. The effect of BMT on crystal structure and electrical property of BT-BNT ceramics was investigated as a function of composition, x, using X-ray diffraction, dielectric spectroscopy, hysteresis and strain measurements. The crystal structure of solid solution BT-BNT-xBMT, where x = 0.00-0.10, successively transforms from tetragonal to pseudocubic symmetry, with increased BMT concentration. Temperature dependence of dielectric constant (ϵ_r) and dielectric loss (tanδ) for BT-BNT-xBMT at various frequencies showed that phase transition of ceramics changed from ferroelectric to relaxor-like behavior as BMT content increased. Furthermore, remanent polarization (P_r), coercive field (E_c) and the normalized strain (d₃₃*) of BT-BNT-xBMT ceramics tend to decrease with increasing BMT concentration.

Keywords:

• BT-BNT-xBMT
• lead free piezoelectric
• phase transition
• electrical properties

Funding

This work was supported by the Thailand Research Fund (TRF), under Grant No. BRG5680006.