Static and dynamic magnetic properties of CoZn substituted Z-type barium ferrite Ba3CoxZn2-xFe24O41Ba3CoxZn2-xFe24O41 composites

The static and dynamic magnetic properties were studied for Z-type barium ferrites Ba3CoxZn2-xFe24O41Ba3CoxZn2-xFe24O41 with x=0x=0–2.0 and the corresponding composites, and the attenuation spectra of the composite materials were calculated from the complex permittivity and permeability. The anisotropy of Ba3CoxZn2-xFe24O41Ba3CoxZn2-xFe24O41 is modified from easy cc-axis to easy cc-plane at x=0.4x=0.4–0.8. The resonance and reflection characteristics of the composites are significantly different for cc-axis and cc-plane anisotropy. For cc-plane anisotropy, only natural resonance exists, while for cc-axis anisotropy, two resonances, the natural resonance and wall resonance, are observed. The static permeability μ0′ and the maximum imaginary permeability μmax″ are increased, while the resonance is shifted to lower frequency, as the Co substitution is decreased. The predicted frequency response of reflection loss showed that Ba3CoxZn2-xFe24O41Ba3CoxZn2-xFe24O41 composites are good electromagnetic materials with low reflectivity and broad bandwidth at microwave frequency.