Enhanced microwave dielectric performances of niobate structured Zn(Nb1-2xZrxWx)2O6 ceramics

Abstract

Zn(Nb1-2xZrxWx)2O6 (0.00 ≤ x ≤ 0.03) ceramics with ultra-low dielectric loss have been synthesized by partially substituting (ZrW)5+ ions at Nb5+ sites. The effect of (ZrW)5+ substitution on the microstructure and microwave dielectric properties was systematically investigated. XRD spectroscopy and Rietveld refinement demonstrate that all samples exhibit a single columbite structure throughout the substitution range. Structural parameters such as octahedral distortion of NbO6 were calculated according to the Rietveld refinement method. It was found that with increasing (ZrW)5+ substitution content, the dielectric permittivity was closely related to the Raman shift of the Ag vibrational peak through fitting the Raman spectra. The Q×f values are mainly influenced by the relative density, the coherence and damping behavior of Ag stretching vibrations. In addition, the variation of τf values is related to the octahedral distortion of NbO6. Notably, Zn(Nb1-2xZrxWx)2O6 (x = 0.01) ceramics sintered at 1260 °C have quite remarkable properties, i.e., εr = 23.73, Q×f = 112,570 GHz, and τf = −55.50 ppm/°C, which make them ideal candidates for ultra-low loss microwave device applications.