Electromagnetic wave absorption properties of Fe1−xCox/Y2O3 (x = 0.33, 0.5, 0.67) nanocomposites in gigahertz range

The electromagnetic wave absorption properties of Fe1−xCox/Y2O3 (x = 0.33, 0.5, 0.67) nanocomposites were characterized in a frequency range of 0.05-20.05 GHz. The real part (ε′r) and imaginary part (ε″r) of relative permittivity almost kept at low constant in 0.05-12 GHz. The imaginary part of relative permeability (μ″r) exhibited a wide peak over 0.5-12 GHz range, in which the μ″r value pertained still high. Compared with α-Fe/Y2O3 composites, the natural resonance frequency (fr) of Fe1−xCox/Y2O3 shifted to the higher frequency range due to the larger magnetic anisotropy of Fe1−xCox nanoparticles. As a result, the resin composites with 80 wt.% Fe1−xCox/Y2O3 powders exhibited good electromagnetic wave absorption properties (RL < −20 dB) in the frequency range of 1.9-9.7 GHz, with thickness of 2.0-7.4 mm, respectively.