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

Solid-phase method was used to synthesize MgMo 1-x W x O 4 (x = 0–0.15) ceramics. The influences of substitution Mo 6+ with W 6+ on crystal structure, vibration characteristics and microwave dielectric properties of MgMo 1-x W x O 4 ceramics were comprehensively studied. X-Ray diffraction illustrated all samples exhibit single-phase monoclinic wolframite structure when x = 0–0.15, in which W 6+ replaces Mo 6+ sites formed solid solution. W 6+ effectively improves sintering properties of the MgMoO 4 , the average grain size and relative density were increased. Raman characterization reveals that suitable W 6+ substitution amount leads to reduction of v 1 A g peaks FWHM and the enhancement of specific v 3 A g peak for Mo/WO 4 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 W 6+ substitution on ε r and τ f for MgMoO 4 . When x = 0.09, MgMo 0.91 W 0.09 O 4 ceramic sintered at 1050 °C has optimal microwave dielectric performance: ε r  = 7.21, Q ×f  = 90,829 GHz, τ f  = −67 ppm/°C.