Structural, dielectric, electrical and optical properties of Li/Fe modified barium tungstate double perovskite for electronic devices


In this communication, the synthesis (solid-state reaction route) and characterization (structural and electrical properties) of Li/Fe modified barium tungstate BaWO4 of chemical formula (BaLi)(FeW)O6 double perovskite have been reported. Analysis of room temperature X-ray diffraction data shows the formation of a new single-phase (double perovskite) of tetragonal symmetry. The calculated average crystallite size and lattice strains are found to be 42 nm and 0.111% respectively. The scanning electron micrograph shows that grains are distributed uniformly with less porosity in the material. Detailed studies of field (frequency) and thermal (temperature) dependence of capacitive (dielectric) and resistive (impedance and conductivity) characteristics of the prepared material have shown the dielectric dispersion, relaxation, and non-Debye type of conduction mechanism respectively of the material. The existence of a non-Debye type of relaxation process and thermally activated relaxation process in the material has been analyzed by using impedance spectroscopy and conductivity techniques respectively. The presence of the depressed semicircular arcs in both Nyquist and Cole-Cole plots confirms the semiconductor nature of the material, which is well supported from ZSIMPWIN fitted impedance data. Study of room temperature Raman spectra supports the incorporation of Li/Fe of LiFeO2 in BaWO4 to produce new double perovskite of a composition BaLiFeWO6 of tetragonal symmetry. Further, as the temperature dependence of resistance shows a good stability factor, sensitivity factor, and thermistor constant, the material may be useful for thermistor-related devices. The nature of I–V characteristics confirms the presence of the Ohmic type of conductivity of the material. The energy bandgap of 2.85 eV, obtained from the UV–visible spectrum, suggests the material may also be used for optoelectronic devices.

Publication Title

Ceramics International