Dielectric and magnetic properties of BaZnZCo2-ZFe16O27/SiO2 microcrystalline glass ceramics prepared by citrate sol-gel

BaZnZCO2-ZFe16O27 (W-type hexaferrite)/SiO2 microcrystalline glass ceramics (Z = 0.0, 0.5, 0.8 and 1.1) were prepared by citrate sol-gel process, they were characterized by x-ray powder diffraction, scanning electron microscopy and thermogravimetry-differential scanning carlorimetry. The results show that the crystallizing temperature of W-type hexaferrite in the system BaO-Fe2O3-CoO-ZnO-SiO2 by sol-gel process is about 1200degreesC, the average grain size of BaZnZCO2-ZFe16O27/SiO2 microcrystalline glass ceramics is about 0.3 mum. The complex dielectric constant and complex permeability of BaZnZCO2-ZFe16O27/SiO2 has been studied as a function of the composition, frequency and annealing temperature. The real part of permeability decreases with increase of frequency, increases with increase of annealing temperature for all samples; the natural resonance, phenomena are observed in imaginary component of permeability-frequency curves for all the samples annealed at 1200degreesC, the natural resonance frequency shifts to lower frequency with increase of zinc content.