Cubic NiFe2O4 particles on graphene–polyaniline and their enhanced microwave absorption properties

The geometrical morphology of magnetic particles has an important influence on microwave absorption properties, but seldom researches have been focused on this issue. In this paper, cubic NiFe2O4 particles on graphene–polyaniline hybrid material were synthesized by a two-step method. TEM results show that most of NiFe2O4 particles have a cubic geometrical morphology. The investigation of the microwave absorbability reveals that the composites exhibit enhanced microwave absorption properties and wide absorption bandwidth. The maximum reflection loss is up to −50.5 dB at 12.5 GHz and the absorption bandwidths exceeding −10 dB are 5.3 GHz (from 11.0 to 16.3 GHz) with a thickness of 2.5 mm. The Cole–Cole plots demonstrate that there are multi-dielectric relaxation processes and the values of C0 indicate that the magnetic loss of the composites is mainly caused by natural resonance and eddy-current effects. Furthermore, our development strategies confirm that the surface modification of polyaniline and cubic NiFe2O4 particles on graphene makes the composites have a promising future in microwave absorption materials.