Preparation, structure and microwave dielectric properties of novel La2MgGeO6 ceramics with hexagonal structure and adjustment of its τf value

A novel La2MgGeO6 ceramic was synthesized through a solid-state reaction process within a sintering temperature range of 1450-1550 degrees C. By a combination of X-ray diffraction and Rietveld refinement analyses, the ceramics were found to have a pure hexagonal phase structure belonging to space group R3/146. The scanning electron microscopy images revealed that the ceramic grains were closely connected. The effects of internal (lattice energy, valence bond, and fraction packing) and external factors (density) on the microwave properties of ceramics were also studied. The ceramic exhibited excellent microwave dielectric performances, with a relative permittivity (epsilon(r)) of 21.2, a quality factor (Q x f) of 52 360 GHz, and a temperature coefficient of resonant frequency (tau(f)) of -44.2 ppm/degrees C, when sintered at 1500 degrees C for 4 h. The tau(f) value of the La2MgGeO6 ceramic doped with CaTiO3 could be adjusted to zero. Particularly, 0.2La(2)MgGeO(6)-0.8CaTiO(3) ceramics have good microwave dielectric properties with tau(f) = +2.1 ppm/degrees C, Q x f = 15 610 GHz, and epsilon(r) = 40.3.

Automated summary

In this study, a novel La2MgGeO6 ceramic was synthesized through a solid-state reaction process and exhibited excellent microwave dielectric properties when sintered at 1500 degrees C. The addition of CaTiO3 dopant allowed for adjustment of the temperature coefficient, leading to improved microwave performance in the mixed ceramic.