Electromagnetic response of magnetic graphene hybrid fillers and their evolutionary behaviors

To understand the principles and mechanisms of the graphene-based electromagnetic response composites, we prepare magnetic graphene–Fe₃O₄ (G–F) hybrid materials and study the electromagnetic properties in the frequency region of 2–18 GHz. The introduction of Fe₃O₄ nanoparticles is found to play a dominant role in the complex permittivity, resulting in changing the surface polarization and interfacial resistivity of the graphene-based fillers. These influences have been found to greatly impact the corresponding microwave absorption and electromagnetic shielding performance. Owing to the syngeneic effects of G and Fe₃O₄, the wax-based composites with G–F presented effective microwave absorption (<−10 dB) and sufficient electromagnetic shielding performance (>20 dB) in the investigated region. The associated mechanisms based on tuning the electromagnetic response of the graphene-based composites via the unique Fe₃O₄ interfaces have been intensively discussed, which promises great guidance in rationally designing and fabricating advanced graphene-based electromagnetic response materials.