Effect of Mn2+ substitution on the dielectric properties of NaMg(PO3)3 ceramics at microwave and terahertz frequencies

In this study, NaMg1-xMnx(PO3)3 (0.00 <= x <= 0.0625) ceramics with low dielectric constant were prepared via the solid-state reaction method. The effects of Mn2+ substitution on the microstructure and dielectric properties (at microwave and terahertz frequencies) of the NaMg(PO3)3 ceramics were studied by means of the Rietveld refinement, morphology, and ionic polarizability analysis. It is obtained that the NaMg0.0975Mn0.025(PO3)3 ceramic sintered at 880 degrees C for 4 h exhibited optimal dielectric properties at microwave frequencies, where er = 4.585, Q x f = 48,313 GHz (@17.228 GHz), and tau f = -40.83 ppm/degrees C. The Q x f and tau f values were changed by 74.2 % and 27.8 %, as compared to the values of 27,728 GHz and -56.52 ppm/degrees C for the pure NaMg(PO3)3 ceramic, respectively. For terahertz frequencies (0.2-1.0 THz), the er values were decreased to 3.79-3.98, and the tans values were between 0.0203 and 0.1152. All the experimental results indicate that this system exhibits great potentials both at microwave and terahertz frequencies.