Magnetic metal/carbon hybrid nanostructures are novel materials having multifunctional properties. Here we report the microwave absorbing properties of nickel/carbon nanostructures synthesized by a controlled pyrolysis method. Their complex dielectric permittivity and magnetic permeability were measured at different microwave frequencies using the technique of cavity perturbation. Reflection losses were evaluated and found to be less than −10 dB over the entire X-band (8–12 GHz) for a thickness of 2.2–2.8 mm. A minimum reflection loss of −45 dB was attained for an absorber thickness of 6.6 mm at 3.13 GHz.
Keywords: Magnetic materials; Carbon; Nickel; Nanocomposites; Microwave absorber; Aerospace materials
Fig. 1. (a) XRD pattern, (b) TEM image (inset: high resolution TEM image), (c) Raman spectrum and (d) Room temperature M–H curve of Ni/C.
Fig. 2. (a) Dielectric permittivity and (b) magnetic permeability spectra of Ni/C in the S and X-band.