Effect of shape of Fe3Al particles on their microwave permeability and absorption properties

Flake-shaped and sphere-shaped Fe3Al powder-paraffine composites have been studied in the microwave frequency range. Mössbauer results show that the flake-shaped Fe3Al particles have easy magnetization plane, which indicates that it is planar-anisotropy. Enhanced permeability is achieved in flake-shaped Fe3Al compared with the sphere-shaped Fe3Al. The permeability is further enhanced by using a rotational orientation method. The complex permeability can be characterized by the superposition of two types of magnetic resonance. The resonance peak at high frequency is attributed to the natural resonance, while the peak at low frequency is attributed to the domain-wall resonance. By employing the shape effect and the rotational orientation, the peak frequency of reflection loss for the oriented sample was adjusted to L-band. The planar-anisotropy Fe3Al powder-paraffine composite can be attractive candidates for thinner microwave absorbers in L-band (1–2 GHz).

► The permeability of composite is enhanced by employing the shape effect.
► A rotational orientation method is used to further improve the permeability.
► The flake-shaped Fe3Al particle is proved to be planar-anisotropy.
► Peak frequency and matching thickness were related to the λ/4 matching condition.
► The sample can be attractive candidates for thinner microwave absorbers.