Crystal structure and improved microwave dielectric properties of ZnZr(1−x)TixNb2O8 ceramics

Abstract

In this work, ZnZr(1−x)TixNb2O8 (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) ceramics were synthesized using solid-state reaction method. Rietveld refinement and Raman analysis were employed to investigate the correlation between crystal structure and microwave dielectric properties. Substitution of Ti4+ for Zr4+ promoted grain growth and ceramic sintering, which is confirmed by SEM results and relative density. Second phase (ZnTiNb2O8), which had poorer microwave dielectric properties than that of ZnTiNb2O8 ceramics, occurred when x ≥ 0.4 because of exceeded solution limit. However, Ti4+ ions enter Zr sites when x ≤ 0.3, and this then affects A/B-site bond lengths and structural characteristics of NbO6 octahedron. This improved microwave dielectric properties and mainly, promoted quality factor $$(Q\times f)$$. Moreover, excellent microwave dielectric properties of $${\varepsilon }_{\text{r}}$$ = 29.75, $$Q\times f$$ = 107,303 GHz, and $${\tau }_{\text{f}} $$= $$- 24.41 {\text{ppm}}/{^\circ{\rm C} }$$ were obtained for ZnZr0.8Ti0.2Nb2O8 (x = 0.2) ceramics sintered at 1150 °C. Thus, the material has a good application prospect in microwave devices.