Synthesis and Characterization of Sb-Doped Bi_0.5(Na_0.5K_0.5)_0.5TiO₃ Ceramics

Abstract

Pure and Sb-doped BNKT (Bi_0.5(Na_0.5K_0.5)_0.5 TiO₃ + x wt.% Sb, (x = 0.2, 0.4, 0.6, 0.8 & 1.0) lead free ceramics were synthesized away from its MPB by solid state reaction method. The crystalline nature of the synthesized ceramic was studied at room temperature using X-ray powder diffraction (XRPD) technique. The temperature dependence of dielectric constant () in temperature range 20–500°C has revealed two phase transitions from ferroelectric to anti-ferroelectric (T_d) and antiferroelectric to paraelectric (T_c) phase. Addition of Sb was found to increase the temperature of these phase transitions, thus increasing the usable temperature range of these ferroelectrics. All samples were found to exhibit normal Curie-Weiss law above its Tc. A linear fitting of the modified Curie- Weiss law to experimental data show that all the samples have diffuse character. The value of γ was found to be between1.38 to 1.65.

Keywords:

• Lead-free piezoelectric material
• Bi_0.(Na_xK_1-x)_0.5TiO₃ ceramic
• dielectric properties

Acknowledgment

We are thankful for the financial support received form the Department of Science & Technology for the Project “Synthesis of High Performance Piezoelectric Ceramic & Crystals for Device Fabrication (SERC Sanction No 100/(IFD)/1637)”. K. Kumar is thankful to UGC for research fellowship in ‘Science for Meritorious Students’.