Effects of particle morphology and crystal structure on the microwave properties of flake-like nanocrystalline Fe3CO2 particles

Flake-like nanocrystalline Fe3CO2 powders synthesized by mechanical alloying have been studied by morphological, structural and magnetic measurements, and compared with sphere-like samples. Complex permeability (mu(r) = mu(r)' - i mu(r)'') and permittivity (epsilon(r) = epsilon(r)' - i epsilon(r)'') was measured in microwave range of frequency (2-18 GHz). Combined with the nature of nanostructure and the dynamics of magnetism, the particle morphology and crystal structure dependence of microwave properties for nanocrystalline particles were studied. By virtue of fine particle size, ultrathin thickness (similar to 0.3 mu m) and nano-sized structure, the flake-like Fe3CO2 particles increased the value of microwave permeability. Simultaneously, multiresonances emerged from the behind of eddy current loss, and were attributed to the surface anisotropy of nanograins. (C) 2006 Elsevier B.V. All rights reserved.