Inorganic Chemistry, Vol.57, No.14, 8264-8275, 2018
Structural Evolution and Microwave Dielectric Properties of Article xZn(0.5)Ti(0.5)NbO(4)-(1-x)Zn0.15Nb0.3Ti0.55O2 Ceramics
Structure and microwave properties of xZn(0.5)Ti(0.5)NbO(4)-(1 - x)Zn0.15Nb0.3Ti0.55O2 ceramics in the range of x = 0.0-1.0 were investigated. Rietveld refinement analysis and Raman spectra show that rutile- and orthorhombic-type solid solutions formed at 0-0.2 and 0.65-1, a composite at 0.2-0.64. In the solid solution regions, chemical bonds are enlarged. In this case, the Zn/Ti/Nb-O1 bond covalency and bond susceptibility are reduced, and lattice energy and thermal expansion coefficient increase along with x increases, which is mainly responsible for the development of microwave dielectric properties. Furthermore, far-infrared spectra and a classical oscillator model were used to discuss the intrinsic dielectric properties in detail. Temperature stable ceramic was obtained for x = 0.516: epsilon(r) similar to 46.11, Q x f similar to 27 031 GHz, and tau(f) similar to -1.51 ppm/degrees C, which is promising for microwave applications.