Realization of negative permittivity of Co2Z hexagonal ferrite and left-handed property of ferrite composite material

The complex permeability and complex permittivity of Co2Z hexagonal ferrite and the microwave properties of ferrite composite material consisting of Co2Z and yttrium iron garnet (YIG) slabs have been discussed in this paper. Negative permittivity is obtained in the semiconductive Co2Z, and Zn doping can further enhance the dielectric resonance. However, the high conductivity prevents Co2Z from producing negative permeability that originates from ferromagnetic resonance, i.e. double negative properties cannot be obtained in semiconductive or metallic ferromagnet. When Co2Z is combined with YIG, the composite structure shows magneto-tunable left-handed properties where Co2Z provides negative permittivity and YIG provides negative permeability.