Lattice vibrational characteristics and structure-property relationships of SrWO₄- x wt.% LiF (x = 0.5–3.0) microwave dielectric ceramics

SrWO₄-x wt.% LiF (SWL, x = 0.5–3.0) ceramics were obtained by a conventional solid-state reaction at 850 °C. The effects of the LiF additive on the phase evolution and dielectric response mechanism of the SWL ceramics were comprehensively studied. The densification temperature of the SWL ceramics was successfully reduced to 850 °C by adding LiF as the sintering additive. The X-ray diffraction data indicated that the SWL ceramics were composite ceramics. The lattice vibrational properties were investigated in depth by Raman scattering and Fourier transform infrared reflectance. The intrinsic dielectric property values fitted by the four-parameter semi-quantum model agreed well with the measured dielectric property values and the theoretical values obtained from the Clausius-Mossotti & damping equations. Moreover, structure-property relationships were obtained by studying the lattice vibrational modes of the SWL ceramics. The SWL ceramic achieved the optimum dielectric property at x = 2.0, with ε_r = 9.03 and Q × f = 47,830 GHz.