The preparation and microwave properties of Ba3ZnZCo2-ZFe24O41/SiO2 microcrystalline glass ceramics by citrate sol-gel process

A series of Ba3ZnZCo2-ZFe24O41/SiO2 microcrystalline glass ceramics with Z=0.0,0.4,0.8 and 1.2 were prepared by citrate sol-gel process. The result showed that Ba3ZnZCo2-ZFe24O41 hexferrite crystallites could be obtained by this process at 1200 degreesC in the system of BaO-Fe2O3-CoO-ZnO-SiO2. The complex dielectric constant and complex permeability of Ba3ZnZCo2-ZFe24O41/SiO2 microcrystalline glass ceramics calcined at different temperature were measured in the range of 200MHz-6 GHz by transmission/reflection coaxial line method. The complex dielectric constant and dielectric loss exhibited insignificant variety in the whole range of measuring frequencies for all samples. The real part of the permeability decreased as the measuring frequency increasing, and calcining temperature had a clear influence on the value of W for Ba3ZnZCo2-ZFe24O41/SiO2 microcrystalline glass ceramics, and so did the content of Zn2+ and Co2+. The natural resonance phenomenon was observed in mu" spectra for all the Ba3ZnZCo2-ZFe24O41/SiO2 microcrystalline glass ceramics. The substitution of Zn2+ ion and annealing temperature closely affect the resonance frequency, the more the Zn2+ ion, the higher the annealing temperature and the lower the resonance frequency.