Structure and microwave dielectric properties of Bi- and Ge-doped calcium molybdate

The powders of Ca1–2xBi2xMo1–xGexO4 solid solutions weresynthesized by the conventional state method and investigated X–ray powder diffraction Raman spectroscopy. compositions crystallize in scheelite structure (sp. gr. I41/a) at 0 x 0.4, but traces bismuth germanates are detected scanning electron microscopy. = 0.5 composition contains several phases with BiVO4- type structures. spectroscopy deformation [BO4]2– polyhedra changes B–O bond length (B Mo, Ge). energy gaps were calculated from diffuse scattering spectra Kubelka-Munk method. Energy gap (Eg) values decrease 3.29 eV to 2.91 eV, probably due 6s2 electrons valence band conductivity germanium. Such Eg can provide photocatalytical activity under UV visible light. electrodynamic parameters ceramic sample measured transmission line average permittivity increases ~10 ~18 which correlates theoretical ε, Vmol total polarizability samples. An increase concentration germanium leads additional resonant peaks S11 S21. These be caused appearance irregular structural domains Bi atoms or induced increased size grains