Enhancing the microwave dielectric performance of SrSm2Al2O7 ceramic by Sr2+ nonstoichiometry and sintering aid addition

Abstract Sr1+xSm2Al2O7+x (0 ≤ x ≤ 0.05) ceramics were prepared by a conventional solid-state reaction method. Slight Sr2+ nonstoichiometry dramatically enhanced the microwave dielectric performance of the ceramics. Compared with the stoichiometric material, Sr-deficient ceramics show greatly enhanced microwave dielectric properties. For x = 0.03, the ceramics exhibited good microwave dielectric properties of ɛr = 18.31, Q × f = 78000 GHz and τf = 2.28 ppm/°C. ZnO and LiF sintering aids were added to the ceramic to reduce the presintering temperature and enhance the microwave dielectric properties of the ceramics. After 0.25 wt% ZnO and 0.25 wt% LiF were added, the ceramics exhibited microwave dielectric properties of ɛr = 19.40, Q × f = 81400 GHz and τf = 3.27 ppm/°C.