Small magnetic Co-doped NiZn ferrite/graphene nanocomposites and their dual-region microwave absorption performance

In this study, novel CNZF (Co-doped Ni-Zn ferrite)/GN (graphene) nanocomposites were prepared by using a facile one-pot hydrothermal method. The phase structure, morphology, and magnetic and electromagnetic performance of the nanocomposites were studied by means of modern measurement techniques. Both sides of the GN sheets were densely covered by CNZF nanoparticles. Moreover, the magnetic nanoparticles had a uniform distribution without the presence of significant agglomeration. The electromagnetic performance indicated that the content of GN played a significant role in determining the dielectric behavior and magnetic anisotropy of the carbon materials, which further influenced the impedance matching and attenuation ability of absorbers. The microwave absorption properties showed that the CNZF/GN-10 nanocomposite exhibited dual-region microwave absorption, with two strong reflection loss peaks of -53.5 dB and -58.3 dB at 9.6 GHz and 5.2 GHz, respectively. The effective absorption bandwidths were as wide as 14.8 GHz, with thicknesses in the range of 1.5-6.0 mm. In addition, such dual-region absorption performance was also observed in CNZF/GN nanocomposites with other compositions. The appearance of dual-region absorption and the mechanism of microwave absorption were discussed in detail. It is expected that this CNZF/GN nanocomposite can be used as a new type of an efficient microwave absorber with light weight.