Investigation on permeability–frequency characteristics and microstructure of composite ferrites

The initial permeability in composite ferrites consisting of low-temperature sintering (Ni 0.15 Cu 0.25 Zn 0.60 )Fe 2 O 4 ferrite and Co 2 Z (Ba 3 Co 2 Fe 24 O 41 ) hexaferrite matrix has been measured from 1 to 1000 MHz. The results reveal that frequency dependence of initial permeability in the composite ferrites is much different from that of pure (Ni 0.15 Cu 0.25 Zn 0.60 )Fe 2 O 4 spinel or Co 2 Z hexagonal ferrite. A simple quantitative estimation of permeability for the composite ferrite materials is proposed and possible magnetic mechanisms generating this kind of difference are discussed.