The microwave dielectric properties of the low‐temperature firing BaZnP ₂ O ₇ ceramics with Co ²⁺ substitution

Abstract In this study, the microwave dielectric properties of Co ²⁺ ‐substituted BaZnP ₂ O ₇ ceramics prepared through conventional solid‐state synthesis were investigated. X‐ray diffraction, Rietveld refinement, energy‐dispersive spectroscopy, and Raman spectroscopy all indicated that BaZn _{1− x} Co _x P ₂ O ₇ ceramics sintered at 875°C were composed of a single phase. The lattice strain and crystallite size were estimated using Williamson–Hall (W–H) method. Both the scanning electron microscopy images and density measurements showed that Co ²⁺ ions had an effect on the grain growth and densification of ceramics. The microwave dielectric properties were influenced by the intrinsic and extrinsic factors that varied with the increase of x value. An optimal performance ( ε _r = 7.62, Q × f = 600 45 GHz, and τ _f = −74 ppm/°C) was achieved at x = .01. The porosity and relative density played a significant role in the dielectric constant ε _r : the denser the ceramic structure, the larger the dielectric constant. The Q × f and τ _f values were negatively correlated with the full width at half maximum of the Raman vibrational peak at approximately 1049 cm ⁻¹ . Moreover, the Q × f value was improved compared to that of the undoped BaZnP ₂ O ₇ ceramics. Therefore, cobalt ion substitution is an effective strategy to enhance the performance of microwave dielectric ceramics.