Crystal structure, vibration characteristics and microwave dielectric properties of low loss MgMo1-xWxO4 solid solution ceramics

Abstract

Solid-phase method was used to synthesize MgMo1-xWxO4 (x = 0–0.15) ceramics. The influences of substitution Mo6+ with W6+ on crystal structure, vibration characteristics and microwave dielectric properties of MgMo1-xWxO4 ceramics were comprehensively studied. X-Ray diffraction illustrated all samples exhibit single-phase monoclinic wolframite structure when x = 0–0.15, in which W6+ replaces Mo6+ sites formed solid solution. W6+ effectively improves sintering properties of the MgMoO4, the average grain size and relative density were increased. Raman characterization reveals that suitable W6+ substitution amount leads to reduction of v1 Ag peaks FWHM and the enhancement of specific v3 Ag peak for Mo/WO4 tetrahedron, which improves the ordered distribution of the crystal structure. The above combined effect results in the increased Q × f value, but has little influence of W6+ substitution on εr and τf for MgMoO4. When x = 0.09, MgMo0.91W0.09O4 ceramic sintered at 1050 °C has optimal microwave dielectric performance: εr = 7.21, Q×f = 90,829 GHz, τf = −67 ppm/°C.