Preparation and microwave hexaferrites by a sol-gel process

Ba4ZnzCo2-zFe36O60 hexaferrites with Z = 2.0, 1.5, 1.0, 0.5, and 0.0 were prepared by a citrate Sol-gel process. The complex dielectric constant and complex permeability of hexaferrite-paraffin wax composites were measured in the range from 0.1 to 6.0 GHz. Measured results showed that both the complex dielectric constant and the dielectric loss exhibited no significant change as the measuring frequency increasing except for the sample with Z = 0.0. The real part of permeability decreased with increasing frequency for all samples in the whole measuring frequency range, and the natural resonance phenomena were observed in all μ" spectrum but Co2U. The results also indicate that the content of zinc closely affects the microwave properties of Ba4ZnzCo2-zFe36O60 ferrites, and the greater the zinc content, the lower the natural resonance frequency is.