Li 5 Ti 2 O 6 F: a new low-loss oxyfluoride microwave dielectric ceramic for LTCC applications

Use of microwave dielectric ceramics can significantly promote the development of communication devices. The primary criteria for determining their applications are excellent microwave dielectric properties and suitability for co-firing with cheap metals (e.g., Ag, Al). This study first reports the low-temperature synthesis of Li 5 Ti 2 O 6 F with a cubic rock salt structure. Li 5 Ti 2 O 6 F was prepared at 880 °C and had ε r of 19.6, Q × f of 79500 GHz, and τ f of − 29.6 ppm/ °C. The infrared reflectivity spectrum revealed that the dielectric contribution of Li 5 Ti 2 O 6 F in the microwave range was mainly affected by phonon absorption. Experimental study indicated that Li 5 Ti 2 O 6 F had good chemical compatibility versus Ag electrode at 880 °C for 2 h. Given these characteristics, Li 5 Ti 2 O 6 F ceramics exhibited potential for low-temperature co-fired ceramic technology.