Electromagnetic properties of Cr-substituted nickel ferrite nanoparticles and their microwave absorption performance

Abstract Chromium (Cr) substituted nickel ferrite nanoparticle was fabricated via a facile coprecipitation route and the microwave absorption performance was investigated within 8.2–18 GHz range. Several characterization approaches have been employed to investigate the morphology, phase composition, chemical composition, and structure of the Ni0·5Cr0·5Fe2O4 nanoparticles. We observed that the nanoparticles are spherical, having compact arrangement and traces of inter-particle porosity. This suggests that the morphology would favor multiple transmission routes for the absorption of EM wave. Analysis of the sample's microwave absorption performance reveals that 20 wt percent loading of Ni0·5Cr0·5Fe2O4 nanoparticles in paraffin can effectively attenuate a large portion of EM wave within 8.2–18 GHz frequency range. The sample achieved an optimum reflection loss value −47.3 dB at 16.0 GHz at 2.5 mm thickness. The EM wave absorption observed can be credited to impedance match, interfacial polarization, and good dielectric/magnetic loss coupling. The absorption bandwidth of the sample covers the X-band and P-band frequency via tuning of the absorber thickness between 2.5 and 4.5 mm. These results show that the Cr-substituted nickel ferrite has good EM properties and can be considered as a possible EM wave absorbing filler.