Complex permittivity, permeability, and microwave absorption of barium ferrite by citrate sol-gel process

摘要

BaFe_(12)O_(19) hexaferrites were prepared by citrate sol-gel process. The formation temperature was much lower than that of the conventional ceramic method. The complex dielectric constant and complex permeability of hexaferrite-paraffin wax composites had been 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 exhibited no significant variation with the measuring frequency increase. It also showed that the real part of permeability decreased as the frequency increasing for all samples, the resonance phenomena due to domain wall resonance was observed in μ″ spectra, the calcining temperature strongly affects the microwave properties of BaFe_(12)O_(19) ferrites, the higher the calcining temperature, the lower the resonance frequency.