Optical, Dielectric, and Electrical Properties of Tungsten-Based Materials with the Formula Li(2-x)NaxWO4 (x=0, 0.5, and 1.5)

In the present study, three chemical compounds, Li2WO4, Li0.5Na1.5WO4, and Li1.5Na0.5WO4, are produced using the solid-solid method. Unlike the compound Li0.5Na1.5WO4, which crystallizes in the orthorhombic system with the space group Pmmm, both compounds Li2WO4 and Li1.5Na0.5WO4 crystallize in the monoclinic system with the space group P2/m. A morphological analysis reveals that all three compounds have a compact structure with some porosity present. An EDX analysis confirms the chemical composition of the three samples. The optical measurements provide information on the optical gaps and Urbach energies of the materials under consideration. Their dielectric characteristics are investigated in a frequency range of 100-106 Hz and at temperatures ranging from 300 to 600 K. Moreover, this research enables us to determine the ferroelectric transition as well as the type of dielectric material. In this study, an investigation of electrical conductivity was conducted for well-defined temperature and frequency values; which provided us with information about the mechanism of conduction and charge carrier transport models.