Crystal structure and enhanced microwave dielectric properties of the Ce2[Zr1−x(Al1/2Ta1/2)x]3(MoO4)9 ceramics at microwave frequency

Dense microwave dielectric ceramics of Ce 2 [Zr 1 − x (Al 1/2 Ta 1/2 ) x ] 3 (MoO 4 ) 9 (CZMAT) ( x = 0.02–0.10) were prepared by the conventional solid-state route. The effects of (Al 1/2 Ta 1/2 ) 4+ on their microstructures, sintering behaviors, and microwave dielectric properties were systematically investigated. On the basis of the X-ray diffraction (XRD) results, all the samples were matched well with Pr 2 Zr 3 (MoO 4 ) 9 structures, which belonged to the space group \(R\bar 3c\) . The lattice parameters were obtained using the Rietveld refinement method. The correlations between the chemical bond parameters and microwave dielectric properties were calculated and analyzed by using the Phillips—Van Vechten—Levine (P—V—L) theory. Excellent dielectric properties of Ce 2 [Zr 0.94 (Al 1/2 Ta 1/2 ) 0.06 ] 3 (MoO 4 ) 9 with a relative permittivity ( ε r ) of 10.46, quality factor ( Q × f ) of 83,796 GHz, and temperature coefficient of resonant frequency ( τ f ) of −11.50 ppm/°C were achieved at 850 °C.