Crystal structure and microwave dielectric properties of BaZnP2O7-based ceramics with Sr2+ substitution.

In this study, Ba 1- x Sr x ZnP 2 O 7 (0 ≤ x ≤ 0.1) ceramics were synthesized at 875–950 °C. The X-ray diffraction and SEM test revealed that Ba 1- x Sr x ZnP 2 O 7 (0 ≤ x ≤ 0.1) ceramics formed a single phase with a P-1 triclinic structure. Moreover, a moderate substitution of Sr2+ is conducive to grain growth and pore reduction. The ε r value was primarily affected by the average bond ionicity (A f i) and porosity, while the unit molecule polarizability contribution was insignificant. The Q × f value was closely related to the packing fraction, U total , and FWHM value of the strongest peak with a wavelength of approximately 1050 cm−1 in Raman spectra. Additionally, the P–O bond significantly influenced the bond ionicity and lattice energy. The Ba 0.92 Sr 0.08 ZnP 2 O 7 ceramic sintered at 925 °C for 4 h exhibits satisfactory microwave performance: ε r = 8.26 ± 0.06, Q × f = 61,677 ± 1781 GHz, τ f = −18.34 ± 0.21 ppm/°C. [ABSTRACT FROM AUTHOR]