Journal of Materials Science, Vol.55, No.20, 8491-8501, 2020
Bond analysis of novel MnZrTa2O8 microwave dielectric ceramics with monoclinic structure
A new type of ceramic, namely MnZrTa2O8, was synthesized after sintering at high temperature in this work. The possible dielectric loss mechanism was discussed by Raman spectroscopy and chemical bond theory. X-ray diffraction indicated that MnZrTa2O8 formed through a reaction between ZrO2 and intermediate MnTa2O6. After sintering at 1350 degrees C, a monoclinic structure with cell parameters a = 4.8370(3) angstrom, b = 5.7163(1) angstrom, c = 5.1398(5) angstrom, beta = 91.7219 degrees was gained for ceramic. Among all bonds, Ta-O with the greatest bond ionicity and lattice energy was the dominant factor that influenced the microwave dielectric properties. The temperature coefficient of the resonant frequency tau(f) changed from - 50.55 to - 41.21 ppm/ degrees C, which was related to the lattice energy. The effect of porosity on dielectric loss was also checked and found to be significant. MnZrTa2O8 ceramic exhibited relative permittivity epsilon(r) 23.0 and enhanced quality factor Q x f 48103 GHz (at 8.97 GHz), which provided a promising candidate for electric components.