Electrical Transport in Lead-Free [(1−x)(Na_0.5Bi_0.5)-xBa]Zr_{1 - y}Ti_yO₃ Ceramics (x = 0, 0.06, and y = 0, 0.96)

Abstract

Lead-free ceramics based on (Na _0.5 Bi _0.5 TiO ₃ , NBT)-(Ba(Ti,Zr)O ₃ , BTZ) were prepared by solid phase hot pressing sintering process and their ac (σ _ac ) and dc (σ _dc ) conductivity have been studied (303–753 K). Low frequency (100 Hz–100 kHz) ac conductivity obeys power law σ _ac ∼ ω ^s characteristic for disordered materials. The frequency exponent s is a decreasing function of temperature and tends to zero at high temperatures. Dc conductivity has thermally activated character and possesses four linear parts with four different activation energies and some discontinous changes. However, σ _ac (T) possesses two linear parts with two different activation energies and more discontinuous changes than dc conductivity. The results was interpreted by correlated hopping model. The NBT-BTZ system is expected to be a new promising candidate for lead-free electronic ceramics.

Keywords:

• Ferroelectric
• Na_0.5Bi_0.5TiO₃-based ceramics
• electric properties