Structural, morphological, electrical, impedance and ferroelectric properties of BaO-ZnO-TiO 2 ternary system

Abstract

A series of (BaO) x -(ZnO) 1-x -TiO 2 (x = 0.1–0.9) ceramic materials were synthesized via the conventional solid-state reaction method and finally sintered at 1200 °C. The diffraction pattern revealed that the cubic (Zn 2 Ti 3 O 8 and BaTiO 3 ) and monoclinic (Ba 2 ZnTi 5 O 13 ) phases were present in the resultant compositions. The morphology was analysed using scanning electron microscope. The presence of metal oxide (M-O) stretching vibrations was confirmed by Fourier transform infrared spectra. The AC electrical properties such as dielectric constant (ε r ), loss tangent (tan δ) and AC conductivity (σ ac ) were investigated as a function of temperature (313–673 K) and frequency (100 Hz–5 MHz). The high dielectric constant and loss values were obtained for higher barium contents (beyond x = 0.5) owing to the presence of smaller number of monoclinic Ba 2 ZnTi 5 O 13 phases. The effect of space-charge polarization was explained from dielectric modulus (M′ and M″) behaviour. The Nyquist plots (Z′ versus Z″) were drawn to justify the electrical conduction mechanism of all compositions. The bulk resistances (R b ) were calculated from Nyquist plots. The room temperature ferroelectric behaviour was illustrated with the help of P-E loop tracer.