摘要
The crystal structure,Raman vibration,chemical bond characteristics,and microwave dielectric properties of Zn_(1-x)Cu_(x)WO_(4)(x=0-0.15)ceramics prepared by a solid-state reaction were investigated by XRD refinement,Raman spectroscopy,P-V-L theory and XPS.According to the P-V-L theory,the properties of the W-O bond are stronger than those of the Zn-O bond,which makes a major contribution to the dielectric properties.The relative permittivity is mainly affected by the average bond ionicity,and the variations in the dielectric loss and tf are mainly attributed to the lattice energy and bond energy.XPS shows that the presence of Cut could produce oxygen vacancy defects,increasing the dielectric loss.Additionally,Raman spectra show that the increasing molecular polarizability causes the Raman shift to move to a low wavenumber,and the changes in Raman intensity and FWHM lead to a decrease in the degree of short-range ordering.Particularly,Zn_(0.97)Cu_(0.03)WO_(4) ceramics sintered at 925℃ showed satisfactory properties(εr=14.20,tanδ=1.473×10^(-4) at 9.087 GHz,and tf=-40 ppm/℃),which can potentially be applied to LTCC technology and indicate that Cu substitution can not only reduce the sintering temperature,but also optimize the dielectric properties.
基金
This work was supported by the National Natural Science Foundation of China under Grant Nos.61771104,U1809215 and 62071106.
