Relaxation in BaBi_xTi_(1−x)O_3−δ Disordered Dielectric Composite Materials

Abstract

BaBi_xTi_(1−x)O_{3 −δ} ceramics are prepared by sol-gel reaction method with different x values (x = 0, 0.05 and 0.1). Structural property of all compositions is studied by XRD and compared with the standard patterns (ICSD card 27977). The crystalline size increases with increase the Bi concentration. The temperature dependence of impedance of BaBi_xTi_1−xO3 (x = 0, 0.05, 0.1) compositions is studied in the frequency range of 100 Hz-1M Hz. Relaxation times (τ) are studied for the different BaBiO₃ concentrations doped into barium titanate ceramics. The impedance characteristics of the laminated type graded composite materials of BaTiO₃ + Ba_0.95Bi_0.05TiO₃ + BaTiO₃ and BaTiO₃ + Ba_0.90Bi_0.1TiO₃ + BaTiO₃ are also studied. The impedance data is analyzed using established models and equivalent circuit parameters are evaluated. The equivalent circuits obtained consist of series or parallel combination of a resistance and a constant phase elements. The results are interpreted in terms of materials properties.

Keywords:

• Ferroelectrics
• composites
• impedance
• laminated type
• sol-gel