Structural, Dielectric and Complex Impedance Studies of BZT

The sintering effect on transition parameters and dielectric characteristics of Ba(Zr0.05Ti0.95)O3 (BZT-5%) ceramics prepared by the sol-gel reaction technique was studied. With X-ray diffraction we studied the influences of sintering time on grain size and structural parameters. The phase transitions and dielectric properties were investigated by measuring the real part of dielectric constant e’ and the loss factor tanδ as a function of temperature (30 - 200 °C) at long range of frequency (1kHz - 2MHz). Two different conduction mechanisms were obtained by fitting the complex impedance data to Cole-Cole equation. The grain and grain boundary resistivity were found to follow the Arrhenius law associated with activation energies: Ea2 below and above Tm for the bulk conduction; and Ea1 below Tm for the grain boundary conduction. Relaxation times extracted using imaginary part of complex dielectric constant e” (ω) were also found to follow the Arrhenius law and showed an anomaly around the phase transition temperature. This results exhibit that bulk conduction is more important than grain boundary conduction. The frequency dependence of resistance and conductivity was interpreted in terms of the non-Debye relaxation.