Microstructure, bonding characteristics, far-infrared spectra and microwave dielectric properties of co-substituted Ce2[(Zr1-x(Zn1/3Sb2/3)x]3(MoO4)9 ceramics

In this contribution, Ce2[(Zr1-x(Zn1/3Sb2/3)x]3(MoO4)9 (CZ1−x(ZS)x) (0 ≤ x ≤ 0.1) ceramics were fabricated using the solid-state reaction method, and the phase composition of the synthesized ceramics was analyzed via XRD and Rietveld refinement. The outcomes revealed that the ceramics, characterized by different x values, constituted a solitary phase with an R-3C space group, and the cell volume demonstrated a decrease with an increase in x value. The examination of the ceramics microwave dielectric characteristics using P−V−L theory reveals that the fi(Ce−O(6)) bond was found to be related to εr, while Q×f was influenced by the average grain size and Uave.(Mo−O), and Eave.(Mo−O) and αave.(Mo−O) were related to the τf value. The optimal properties were achieved at 750 °C (x = 0.02), resulting in εr = 10.08, Q×f = 100,954 GHz, τf = −12.46 ppm/°C. The infrared reflection spectrum analysis revealed that the primary polarization contribution was due to the dielectric response of intrinsic phonons. Additionally, the effects of three different complex ions (Zn1/2Sb2/3)4+, (Zn1/2Ta2/3)4+, and (Zn1/2Nb2/3)4+ doping on the properties of Ce2Zr3(MoO4)9 ceramics were investigated using SEM, packing fraction, and chemical bond analysis. The results showed that (Zn1/2Sb2/3)4+ doping was effective in improving the grain size and apparent density of Ce2Zr3(MoO4)9 ceramics, and the high packing fraction and U(Mo-O) were found to be the primary intrinsic factors for the optimal properties.