Effects of W6+ on the microstructure, sinterability, lattice vibration, and dielectric properties of Pr2Zr3(Mo1˗xWxO4)9 ceramics at microwave/terahertz/infrared regions

In this article, a series of Pr2Zr3(Mo1−xWxO4)9 ceramics were prepared using the solid-state reaction method and investigated in terms of phase compositions, lattice stress, lattice vibrations, and dielectric properties at microwave, terahertz, and infrared regions. X-ray diffraction (XRD) analysis revealed that all ceramics possess a trigonal structure (R-3c space group) with no discernible second-phase presence. Moreover, the ceramics exhibit oriented growth along the (0,0,18) crystal plane. The densification of all ceramics occurred within the range of 800–825 °C. Raman spectroscopy exhibited a minor blue shift in the predominant peak as the x value increased. The complex permittivity (ε′ and ε″) were evaluated using both infrared reflectance spectrum and terahertz time-domain (THz-TD) spectroscopy. Interestingly, the THz-TD spectral data exhibited a closer agreement with the measured values, which was attributed to a significant relaxation polarization mechanism. Specifically, the peaks below 400 cm−1 contributed significantly to the dielectric parameters, accounting for 88.4% and 95.7% of ε′ and ε″, respectively. As a result of these findings, it is suggested that Pr2Zr3(Mo0.94W0.06O4)9 (εr = 9.82, Qf = 81,892 GHz, τf = −17.90 ppm/°C) ceramics synthesized at 825 °C hold promise as potential materials for high-frequency communication circuits.