Influence of carbon black addition on the microwave absorption properties of neodymium-doped barium hexaferrite

The effect of carbon black (CB) addition on the microwave absorption properties of neodymium-doped barium hexaferrite (BaNd0.04Fe11.96O19) nanoparticles has been studied in X-band. The BaNd0.04Fe11.96O19 nanoparticles are synthesized by the sol-gel auto-combustion reaction. The XRD and SEM analysis confirmed the formation of hexagonal shaped barium hexaferrite particles. The doping of neodymium in barium hexaferrite is confirmed from EDAX pattern. Composites of magnetic BaNd0.04Fe11.96O19 nanoparticles and conducting CB are developed by ball milling process. The addition of carbon black in ferrite increases the complex dielectric constant of the ferrite due to interfacial polarization. The magnetic properties of the composites such as saturation magnetization and magnetic losses are observed to decrease with the increasing content of carbon black. The maximum reflection loss of -51.35 dB is observed for the composite containing 80% BaNd0.04Fe11.96O19 and 20% CB at coating thickness of 2.35 mm. Also, the - 10 dB bandwidth for microwave absorption reaches to 2.55 GHz in X-band. The high microwave absorption resulted from the high EM attenuation and impedance matching of material with free space.