Gigahertz range electromagnetic wave absorbers made of amorphous-carbon-based magnetic nanocomposites

Jiu Rong Liu, Masahiro Itoh, Takashi Horikawa, Ken Ichi MacHida, Satoshi Sugimoto, Toru Maeda

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94 Citations (Scopus)


Nanocomposite magnetic materials α-FeC (a), Fe2 BC (a), and Fe1.4 Co0.6 BC (a) were prepared by mechanically grinding α-Fe, Fe2 B, or Fe1.4 Co0.6 B with amorphous carbon [C (a)] powders. Complex permittivity, permeability, and electromagnetic wave absorption properties of resin compacts containing 40-vol % composite powders of α-FeC (a), Fe2 BC (a), and Fe1.4 Co0.6 BC (a) were characterized according to a conventional reflection/transmission technique. The real part (εr′) and imaginary part (εr″) of the relative permittivity are low and almost independent of frequency between 0.05 and 40 GHz. The Imaginary part (μr″) of the relative permeability exhibited wide peaks in the 1-9-GHz range for α-FeC (a), in the 2-18-GHz range for Fe2 BC (a), and in the 18-40-GHz range for Fe1.4 Co0.6 BC (a) owing to their different magnetocrystalline anisotropy field (HA) values. Consequently, the resin compacts of 40-vol % α-FeC (a), Fe2 BC (a), and Fe1.4 Co0.6 BC (a) powders provided good electromagnetic (em) wave absorption performances (reflection loss<-20 dB) in ranges of 4.3-8.2 GHz (G band), 7.5-16.0 GHz (X band), and 26.5-40 GHz (Q band) over absorber thicknesses of 1.8-3.3, 1.2-2.2, and 0.63-0.82 mm, respectively. Our experimental results demonstrate that the amorphous-carbon-based magnetic nanocomposites are promising for the application to produce thin and light EM wave absorbers.

Original languageEnglish
Article number054305
JournalJournal of Applied Physics
Issue number5
Publication statusPublished - 2005 Sep 1
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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