Electromagnetic wave absorption properties of α-Fe/Fe3B/Y2O3 nanocomposites in gigahertz range

Nanocomposites alpha-Fe/Fe3B/Y2O3 were prepared by a melt-spun technique, and the electromagnetic wave absorption properties were measured in the 0.05-20.05 GHz range. Compared with alpha-Fe/Y2O3 composites, the resonance frequency (f(r)) of alpha-Fe/Fe3B/Y2O3 shifted to a higher frequency range due to the large anisotropy field (H-A) of tetragonal Fe3B (similar to0.4 MA/m). The relative permittivity (epsilon(r)=epsilon(r)(')-jepsilon(r)()) was constantly low over the 0.5-10 GHz region, which indicates that the composite powders have a high resistivity (rho=similar to100 Omega m). The effective electromagnetic wave absorption (reflection loss <-20 dB) was obtained in a frequency range of 2.7-6.5 GHz on resin composites of 80 wt % alpha-Fe/Fe3B/Y2O3 powders, with thickness of 6-3 mm, respectively. A minimum reflection loss of -33 dB was observed at 4.5 GHz with an absorber thickness of 4 mm. (C) 2003 American Institute of Physics.