High quality factor microwave dielectric ceramics in the (Mg1/3Nb2/3)O2–ZrO2–TiO2 ternary system

Novel high quality factor microwave dielectric ceramics (1−x)ZrTiO4−x(Mg1/3Nb2/3)TiO4 (0.325≤x≤0.4) and (ZrTi)1−y(Mg1/3Nb2/3)yO4 (0.2≤y≤0.5) with the addition of 0.5 wt% MnCO3 in the (Mg1/3Nb2/3)O2–ZrO2–TiO2 ternary system were prepared, using solid-state reaction method. The relationship between the structure and microwave dielectric properties of the ceramics was studied. The XRD patterns of the sintered samples reveal the main phase belonged to α-PbO2-type structure. Raman spectroscopy and infrared reflectivity (IR) spectra were employed to evaluate phonon modes of ceramics. The 0.65ZrTiO4−0.35(Mg1/3Nb2/3)TiO4−0.5 wt% MnCO3 ceramic can be well densified at 1240°C for 2 hours and exhibits good microwave dielectric properties with a relative permittivity (er) of 42.5, a quality factor (Q×f) value of 43 520 GHz (at 5.9 Ghz) and temperature coefficient of resonant frequency (τf) value of −5ppm/°C. Furthermore, the (ZrTi)0.7(Mg1/3Nb2/3)0.3O4−0.5 wt% MnCO3 ceramic sintered at 1260°C for 2 hours possesses a er of 31.8, a Q×f value of 35 640 GHz (at 6.3 GHz) and a near zero τf value of −5.9 ppm/°C. The results demonstrated that the (Mg1/3Nb2/3)O2–ZrO2–TiO2 ternary system with excellent properties was a promising material for microwave electronic device applications.