Synthesis, Characterization and Electrical Properties of La Modified SrBi₄Ti_3.975Zr_0.025O₁₅

Abstract

Ceramic samples of composition Sr(Bi_4-xLa_x)(Ti_3.975Zr_0.025)O₁₅ (x = 0.025, 0.05 ,0.075 and 0.1) is prepared by solid-state method. It is characterized by X-ray diffraction (XRD), scanning electron micrograph (SEM) and energy dispersive spectra (EDS). From XRD and SEM analysis, single-phase formation is identified with orthorhombic structure and particle size is calculated. Compositions are confirmed from EDS. Electrical properties are studied by impedance spectroscopy and conductivity. From impedance, AC and DC conductivities are recorded in the temperature range room temperature (RT) – 600°C. From impedance data, various parameters like bulk resistance or grain resistance (R_b or R_g), bulk capacitance or grain capacitance (C_b or C_g), grain boundary resistance (R_gb), and grain boundary capacitance (C_gb) are determined. Grain and grain boundary relaxation times (τ_g, τ_gb) are also evaluated as a function of temperature. From AC and DC conductivity plots activation energies for conduction are obtained. Results obtained lead to improved understanding of conductivity of samples.

Keywords:

• Impedance spectroscopy
• DC conductivity
• AC conductivity