Ni-Zn Ferrite-graphene Nanohybrids: Synthesis and Characterization of Magnetic and Microwave Absorbing Properties

An in-situ deposition technique was used in the synthesis of Ni-Zn ferrite-graphene (NZFG) nanohybrids. The XRD patterns revealed the presence of cubic spinel structure of Ni-Zn ferrite (NZF) nanoparticles with good crystallinity and small crystallite sizes. The SEM images showed NZF nanoparticles were uniformly deposited on graphene sheets. The effect of different loading amounts of NZF nanoparticles in the nanohybrids was also investigated by tuning the mass ratio of FeCl3 and expanded graphite (EG). The magnetic measurements showed ferromagnetic behaviour with low coercivity. Improvements in saturation magnetization of the nanohybrids can be seen with increasing mass ratio of FeCl3: EG. The microwave absorption properties were determined based on the measured relative complex permittivity and permeability. For the nanohybrids, the minimum reflection loss (R-L) obtained is -37.57 dB at 7.54 GHz and the absorbing bandwidth in which the R-L is less than -10 dB is 7.30 GHz when the NZF content was 79 wt. % at 7 mm thickness. The enhancement in the minimum R-L was due to the synergistic effect between NZF nanoparticles and graphene.