Effects of Zn2+ substitution on the dielectric properties, chemical bonding properties, and crystal structure of Mg3(PO4)2 ceramics

A series of (Mg_1-xZn_x)₃(PO₄)₂ (x = 0.02-0.10) microwave dielectric ceramics were fabricated by the solid-state reaction method and investigated in terms of crystal structure, chemical bond properties, and dielectric properties were analyzed. The XRD data indicates that (Mg_1-xZn_x)₃(PO₄)₂ samples belong to the monoclinic crystal with P2₁/c space group and no detectable secondary phases. The Rietveld refinement was employed to obtain crystal parameters. In addition, the results of chemical bond properties reveal that the lattice energy and ionicity of Mg(2)-O(3) bonds play a primary effect on the dielectric loss and dielectric constant, respectively. The bond energy of Mg(l)-O(2) bonds plays a dominant role in thermal stability. The far-infrared spectroscopy was employed to explore the intrinsic dielectric parameters, and the results showed that peaks below 400 cm^-l contributed 78.9% to ε′ and 99.1% to ε″. The Raman data demonstrated that the Raman shift and FWHM exhibit an important influence on Q × f. The optimal performance was achieved in (Mg_0.94Zn_0.06)₃(PO₄)₂ ceramics: ε_r = 5.00, Q × f = 84,674 GHz, τ_f = -59.98 ppm/°C.