▎ 摘　　要

In this work, magnesium ferrite (MgFe2O4) microspheres decorated nitrogen-doped reduced graphene oxide (NRGO) hybrid composite was fabricated through a solvothermal and hydrothermal two-step method. Results manifested that the three-dimensional netlike structure consisting of MgFe2O4 microspheres and crumpled NRGO was well constructed in the as-synthesized hybrid composite. Significantly, both hybridization with reduced graphene oxide (RGO) and nitrogen doping had few effects on the size of MgFe2O4 microspheres. Furthermore, the influences of hybridization with RGO, nitrogen doping and filler loadings on the electromagnetic absorption properties were carefully examined. It was found that both hybridization with RGO and nitrogen doping were effective strategies to enhance the electromagnetic absorption capacity of MgFe2O4 microspheres. Remarkably, the as-prepared NRGO/MgFe2O4 hybrid composite presented excellent electromagnetic absorption performance, that was the minimum reflection loss of -48.0 dB at 5.2 GHz, and maximum absorption bandwidth of 4.8 GHz under a low filler loading of 25.0 wt% and a small matching thickness of 2.0 mm. In addition, the potential electromagnetic absorption mechanisms were revealed. Therefore, our results could be beneficial to fabricating graphene-based dielectric/magnetic hybrid composites as high-efficiency electromagnetic absorbers. (C) 2020 Elsevier B.V. All rights reserved.