Gigahertz range absorption properties of /spl alpha/-Fe/Y/sub 2/O/sub 3/, FeCo/Y/sub 2/O/sub 3/, and /spl alpha/-Fe/Fe/sub 3/B/Y/sub 2/O/sub 3/ nanocomposites

Complex permittivity, permeability, and electromagnetic wave absorption properties of resin compacts containing 50 vol% composite powders of /spl alpha/-Fe/Y/sub 2/O/sub 3/, FeCo/Y/sub 2/O/sub 3/, and /spl alpha/-Fe/Fe/sub 3/B/Y/sub 2/O/sub 3/ were investigated in this study. Real part (/spl epsiv//sub r/') and imaginary part (/spl epsiv/"/sub r/) of the relative permittivity almost kept low constant between 0.05 and 18 GHz. Imaginary part (/spl mu/"/sub r/) of the relative permeability exhibited wide peaks in the 1-4 GHz range for /spl alpha/-Fe/Y/sub 2/O/sub 3/, in the 1-8 GHz range for FeCo/Y/sub 2/O/sub 3/, and in the 2-10 GHz range for /spl alpha/-Fe/Fe/sub 3/B/Y/sub 2/O/sub 3/ owing to their different magnetocrystalline anisotropy field (H/sub A/) values. Consequently, the resin compacts of 50 vol% /spl alpha/-Fe/Y/sub 2/O/sub 3/, FeCo/Y/sub 2/O/sub 3/, and /spl alpha/-Fe/Fe/sub 3/B/Y/sub 2/O/sub 3/ 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.