Gigahertz range absorption properties of α-Fe/Y2O3, FeCo/Y2O3, and α-Fe/Fe3B/Y2O3 nanocomposites

Complex permittivity, permeability, and electromagnetic wave absorption properties of resin compacts containing 50 vol% composite powders of α-Fe/Y₂O₃, FeCo/Y₂O₃, and α-Fe/Fe₃B/Y₂O₃ were investigated in this study. Real part (ε_r\´) and imaginary part (ε"_r) of the relative permittivity almost kept low constant between 0.05 and 18 GHz. Imaginary part (μ"_r) of the relative permeability exhibited wide peaks in the 1-4 GHz range for α-Fe/Y₂O₃, in the 1-8 GHz range for FeCo/Y₂O₃, and in the 2-10 GHz range for α-Fe/Fe₃B/Y₂O₃ owing to their different magnetocrystalline anisotropy field (H_A) values. Consequently, the resin compacts of 50 vol% α-Fe/Y₂O₃, FeCo/Y₂O₃, and α-Fe/Fe₃B/Y₂O₃ powders provided good electromagnetic wave absorption performances (reflection loss<-20 dB) in ranges of 2.0-3.5 GHz, 2.1-5.0 GHz, and 2.7-6.5 GHz over absorber thicknesses of 3.0-5.0 mm, 3.1-7.2 mm, and 3.0-6.0 mm, respectively.