Correlation of crystal structure and microwave dielectric characteristics of temperature stable Zn1−xMnxZrNb2O8 (0.02≤x≤0.1) ceramics

Wolframite-structured Zn 1−x Mn x ZrNb 2 O 8 (x=0.02, 0.04, 0.06, 0.08, 0.10) ceramics were synthesized by the conventional solid-state method. The effects of Mn 2+ substitution on the crystal structure, crystal chemistry and microwave dielectric properties of ZnZrNb 2 O 8 were investigated. Bond ionicity, lattice energy and thermal expansion of the ceramics were calculated by the complex chemical bond theory, which were used to investigate the correlation between intrinsic factors and microwave dielectric properties. The ε r values were dependent on the electronic oxide polarizabilities of Zn 1−x Mn x ZrNb 2 O 8 ceramics. The Q·f values decreased from 51,300 to 44,900   GHz, which could be explained in terms of packing fraction and lattice energy. The τ f values were shifted to positive direction with the increase of Mn 2+ contents, which indicated that the distortion of the [BO6] octahedral was closely related to τ f values. In addition, thermal expansion coefficient also affected the temperature stability of ceramics. Typically, an excellent microwave dielectric property was obtained in the Zn 0.9 Mn 0.1 ZrNb 2 O 8 with a ε r of 29.43, an appropriate Q·f of 44,900   GHz and a near zero τ f of −5.61   ppm/°C.