Structural, topological, dielectric, and electrical properties of a novel calcium bismuth tungstate ceramic for some device applications

This article describes the characterization (structural, topological, dielectric, and electrical properties) of a lead-free complex perovskite Ca3Bi2WO9 (CBWO) prepared by a solid-state reaction method. The room-temperature X-ray structural analysis of the material suggests crystallization of the material in monoclinic crystal symmetry with average crystallite size and lattice strain of 73.29 nm and 0.0023, respectively. Studies of microstructural and compositional properties of the sample using scanning electron microscopy (SEM) and EDX (energy-dispersive analysis X-ray) revealed the good quality of the sample (uniformity and compactness of grains and grain boundary). A careful examination of the temperature and frequency dependence of the impedance, dielectric, and ac conductivity characteristics of the material shows the existence of large dielectric dispersion, relaxation mechanisms, and a non-Debye type of conduction mechanism in it. The diminishing of resistance or radius of semicircular arcs in Nyquist plots and impedance analysis show the semiconductor behavior of the material. Fitted parameters obtained using ZSIMPWIN software also support this nature. The nature of field-dependent polarization [hysteresis loops (P-E)] shows that ferroelectricity may exist in the sample. The negative temperature coefficient of resistance (NTCR) character, which applies to NTC thermistor application, is shown by calculating the temperature coefficient of resistance (TCR) and thermistor constant (beta).