NdNb1-x(Mg1/4W3/4)xO4 (0.02≤x≤0.06) solid solution characterized by infrared spectrum and complex chemical theory.

Abstract The dependence of the bond characters and crystal structure on microwave dielectric properties of NdNb 1- x (Mg 1/4 W 3/4) x O 4 (x = 0.02–0.06) solid solution ceramics is investigated. X-ray diffraction and Rietveld refinement analysis both indicate a formation of single monoclinic phase in the whole range. Based on complex chemical bond theory, theoretical dielectric constant of the complex crystal is slightly lower than observed one, which is consistent with the analysis of infrared reflectivity spectra. The Q × f (quality factor) values are associated with the total lattice energy and average grain size. Increment of Nb-site bond energy generates a more stable structure, which makes τ f (temperature coefficient of resonant frequency) continuously move towards zero. Besides, far-infrared reflectivity spectra illustrates that low-frequency modes play primary role of intrinsic dielectric properties. Excellent microwave dielectric properties and an optimal combination are: ε r = 19.59, Q × f = 50339 GHz, τ f = −39.62 ppm/°C at x = 0.04. Highlights • NdNb 1- x (Mg 1/4 W 3/4) x O 4 (x = 0.02–0.06) solid solution ceramics have excellent microwave dielectric properties. • Far-infrared reflectivity spectra illustrates that low-frequency modes play primary role of intrinsic dielectric properties. • The relationship between microwave dielectric properties and the chemical bonds characteristics is investigated. [ABSTRACT FROM AUTHOR]