The preparation and microwave properties of Ba 2Zn xCo 2− xFe 28O 46 hexaferrites

Abstract

Ba 2Zn x Co 2− x Fe 28O 46 hexaferrites with x=2.0, 1.6, 1.2, 0.8, 0.4 and 0.0 were prepared by citrate sol–gel process. The reaction temperature was much lower than that of the conventional ceramic method. The complex dielectric constant and complex permeability of hexaferrite–paraffin wax composites were measured by the transmission/reflection coaxial line method in the range from 200 MHz to 6 GHz. The measurement results showed that both the complex dielectric constant and dielectric loss tangent showed no significant variation as frequency increases with dielectric loss tangent near to zero at all measuring frequencies. It also showed that the real part of permeability decreased with frequency increase for all samples in the whole measuring frequency range, and the natural resonance phenomenon could be observed in μ″ spectrum. The substitution of zinc ion had a close effect on the microwave properties of Ba 2Zn x Co 2− x Fe 28O 46 ferrites, as increasing zinc ion content lowered the natural resonance frequency.