Structural, dielectric, electrical and optical properties of a double perovskite: BaNaFeWO6 for some device applications

Abstract

In this paper, the synthesis (by solid-state reaction route) and characterization (structural, microstructural, electrical, and optical properties) of the BaNaFeWO6 lead-free double perovskite are reported. Room temperature structural analysis suggests that the material crystallizes in monoclinic crystal symmetry with average crystallite size and lattice strain of 55 nm and 0.023% respectively. The incorporation of the Na/Fe at both sites (Ba and W) of BaWO4 is confirmed from the room temperature Raman study. A study of microstructural and compositional characteristics of the sample by using scanning electron microscopy (SEM) and EDAX (energy dispersive analysis X-ray) has provided the quality (uniform and compactness) of the sample. The detailed studies of the frequency and temperature dependence of dielectric, impedance, and conductivity properties of the material suggest the presence of high dielectric dispersion, non-Debye conduction, and relaxation mechanism in it. The semiconducting nature is confirmed by the decreasing resistance or radius of semicircular arcs in both impedance analysis and Nyquist plots. This nature is also well supported by fitted parameters evaluated using ZSIMPWIN software. The temperature dependence of resistance provides a good stability factor, sensitivity factor, and thermistor constant, which may be useful for applications in the fields of the thermistor-related devices. The field-dependent polarization (P-E) hysteresis loop suggests the possibility of ferroelectricity in the sample. The sample has an energy bandgap of 2.72 eV deduced from its UV–visible spectrum, which may be useful for some applications in optoelectronic devices