Improved Microwave Dielectric Properties of LiNb0.6Ti0.5O3 Ceramics with Zr Substitutions.

The influences of Zr⁴⁺ substituted for Ti⁴⁺ on the microwave dielectric properties of LiNb_0.6Ti_(0.5−x)Zr_xO₃ (0.00 ≤ x ≤ 0.14) ceramics prepared via conventional solid-state method have been studied and are discussed. X-ray diffraction analysis indicated that the Li_1.075Nb_0.625Ti_0.45O₃ phase was formed, while a small trace of ZrO₂ was observed when x reaches 0.08. With the increase of Zr⁴⁺ substitution, variation of the dielectric constant (ε_r) was dominated by phase constitutions and densification. The quality factor (Q × f) showed a continuously decrease tendency, which was attributed to the increasing number of grain boundaries and the content of the secondary phase. The temperature coefficient of the resonant frequency (τ_f) value shifted from 30.60 ppm/°C to − 14.50 ppm/°C. Temperature-stable microwave dielectric ceramics was obtained with ε_r = 63.14, Q × f = 4626 GHz and τ_f =1.38 ppm/°C, at x = 0.10. [ABSTRACT FROM AUTHOR]