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

Wolframite-structured Zn1−xMnxZrNb2O8 (x=0.02, 0.04, 0.06, 0.08, 0.10) ceramics were synthesized by the conventional solid-state method. The effects of Mn2+ substitution on the crystal structure, crystal chemistry and microwave dielectric properties of ZnZrNb2O8 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 εr values were dependent on the electronic oxide polarizabilities of Zn1−xMnxZrNb2O8 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 τf values were shifted to positive direction with the increase of Mn2+ contents, which indicated that the distortion of the [BO6] octahedral was closely related to τf values. In addition, thermal expansion coefficient also affected the temperature stability of ceramics. Typically, an excellent microwave dielectric property was obtained in the Zn0.9Mn0.1ZrNb2O8 with a εr of 29.43, an appropriate Q·f of 44,900 GHz and a near zero τf of −5.61 ppm/°C.