Ultralow loss and temperature stability of Li3Mg2NbO6-xLiF ceramics with low sintering temperature

Abstract Novel temperature stable Li 3 Mg 2 NbO 6 - x LiF (x = 0.5–8 wt %) ceramics with ultralow loss were fabricated by the solid-state reaction process. The influence of LiF addition on the sintering, grain growth and morphology, and improved microwave dielectric characteristics was investigated. A single orthorhombic Li 3 Mg 2 NbO 6 structure could be confirmed by Raman spectra and XRD patterns. Dense and homogeneous microstructure could be obtained with ∼10 μm average grain size. Results demonstrated that the e r values were relevant to bulk density and the high Q×f values were influenced by the large grain sizes. The τ f values depend on porosity corrected dielectric constant. Notably, the remarkably desirable microwave dielectric characteristics: e r  = 15.4, Q×f  = 100,000 GHz, τ f  = −3.1 ppm/°C were achieved for the Li 3 Mg 2 NbO 6 ceramics with x = 6 wt% sintered at 925 °C, which could be applied for ultra-low loss LTCC applications.