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 in morphology, having closely compact arrangement and traces of inter-particle porosity, suggesting that the morphology would favor multiple transmission routes for the propagation of EM wave. Analysis of the electromagnetic wave absorption 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. 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 was credited to impedance match, interfacial effects, and good dielectric/magnetic loss coupling. The absorption bandwidth of the sample covers the X-band and P-band frequency through tuning of the 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.