Electromagnetic Wave Absorption Properties of Resin Composites Containing α-Fe/Co_0.5Fe_2.5O₄ Mixed Powders

Abstract

In this work, resin composites of α-Fe and Co_0.5Fe_2.5O₄ mixed powders were prepared and their electromagnetic wave absorption properties were investigated. Two peaks were observed in the frequency dependence of relative permeability, and the magnetic resonance frequency (f_r) corresponding to the highest peak of the imaginary part of relative permeability (μ_rʺ) could be controlled from 0.91 to 13.3 GHz according to the mixing ratio of the magnetic powders. The results suggest that changes in the effective demagnetizing field H_d^eff with changes in the mixing ratio influenced the peak shift of permeability. A matching frequency with reflection loss of less than -20 dB could be tuned from 0.30 to 9.95 GHz by controlling mixing ratio of the α-Fe and Co_0.5Fe_2.5O₄ mixed powders and the thickness of the composites.