Study on the Complex Permeability of NiCuZn Ferrites

초록

In characterization of frequency dependence of spinel ferrite materials, the dispersion phenomena due to relaxation cal be observed at same frequency range, and this is related with the ferrite composition and their initial permeability. Therefore it is important to investigate the variation of complex permeability with frequency for the applications, which gives useful information for application in the high-frequency range. In this work, the cole-cole plots for NiCuZn ferrites were presented to describe its relaxation process with a semi-circle curve of complex permeability is characterized by the magnitude of initial permeability. The characteristics of the complex permeability of (NiyCu0.2Zn0.8-yO)1-w(Fe2O3)1+w with various Ni and Co3O4 contents were also investigated in this work. The resonance frequency increased as Ni content becomes higher, where the loss was low. the μ" value decreased with increasing Fe2O3 deficiency, but the resonance frequency(fμ"max) was only slightly affected by Fe2O3 deficiency. In case of Co3O4 addition to the NiCuZn ferrites, the fμ"max increased since the initial permeability decreased with the amount of Co3O4. It is concluded that the Ni content in the NiCuZn ferrite is a dominant factor for the total loss of these spinel ferrites.