Monodomain Design and Permeability Study of High-Q-Factor NiCuZn Ferrites for Near-Field Communication Application

Abstract

For application in near-field communication (NFC) systems, monodomain NiCuZn ferrite has been prepared by the conventional solid-state reaction method. The results show that the monodomain design is effective; the Q factor of this kind of sample with 0.3 wt.% Co2O3 doping could be as high as 118.19. To obtain guidelines for preparing high-quality materials, the magnetic spectra of monodomain ferrite samples are studied via a numerical fitting method. According to the results of this permeability spectra fitting, the magnetic spectra of our prepared samples are mainly determined by the static spin susceptibility K s, spin resonance frequency ω 0, and relaxation frequency ω r. Specifically, we find that ω r varies with the frequency of the external field f. Furthermore, we demonstrate that Co2O3 influences the relationship between ω r and the frequency of the external field. According to theoretical expectations, a higher Q factor at frequency of 13.56 MHz could be obtained by using an appropriate Co2O3 content.