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[Zr1-x(Al1/2Ta1/2)(x)](3)(MoO4)(9) (CZMAT) (x = 0.02-0.10) were prepared by the conventional solid-state route. The effects of (Al1/2Ta1/2)(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 Pr2Zr3(MoO4)(9) structures, which belonged to the space group R<(3)over bar >c. 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(Al1/2Ta1/2)(0.06)](3)(MoO4)(9) with a relative permittivity (epsilon(r)) of 10.46, quality factor (Q x f) of 83,796 GHz, and temperature coefficient of resonant frequency (tau(f)) of -11.50 ppm/degrees C were achieved at 850 degrees C.