Enhanced Microwave Absorption of Reduced Graphene Oxide/Ni_0.4Zn_0.4Co_0.2Fe₂O₄ Composite at Ultrathin Thickness

Reduced graphene oxide (rGO)-anchored Ni_0.4Zn_0.4Co_0.2Fe₂O₄ (NZCF) composites were successfully synthesized by a hydrothermal process and then mixed with paraffin wax. The phase composition and microstructure were investigated by Fourier transform infrared (FT-IR) spectroscopy, x-ray diffraction, and scanning electron microscopy. The results confirmed that the rGO particles covered the modified ferrite grains, and the NZCF particles exhibited a typical spinel structure with the characteristic of the Fd3m cubic groups. In addition, the electromagnetic parameters were measured via a vector network analyzer. The composites with paraffin wax exhibited excellent electromagnetic wave absorption performance, comparable or superior to that of most reported absorbers. The reflection loss was excellent, with a value of −47.10 dB with ultralow thickness of only 0.44 mm obtained from the rGO/NZCF composite with paraffin volume fraction of 20%, and the maximum bandwidth reached 3.7 GHz with merely 1.5 mm in thickness. Therefore, the rGO/Ni_0.4Zn_0.4Co_0.2Fe₂O₄ composites are potential candidates for electromagnetic wave absorption applications.