Electromagnetic-wave-absorption properties of wire-like structures self-assembled by FeCo nanocapsules

Abstract

Al2O3-coated FeCo nanocapsules were synthesized by the arc-discharge method and three-dimensional wire-like macro-aggregates were self-assembled simultaneously by nanocapsules. The electromagnetic (EM) parameters (i.e. the relative permeability and permittivity) were measured at 2–18 GHz. As a consequence of the surface- and shape-anisotropy energy of the nanocapsules, a natural resonance at 6 GHz is dominant in the microwave absorption properties. A reflection loss (RL) exceeding −20 dB was obtained in the frequency range 4.2–18 GHz for absorber thicknesses of 1.3–6 mm. An optimal RL of −51 dB was found at 10.2 GHz for an absorber thickness of 2 mm. As a result, the Al2O3-coated FeCo nanocapsules show good prospects of being applied in EM wave absorptive devices. (Some figures in this article are in colour only in the electronic version)