Bimetallic Oxalate Rod-Derived NiFe/Fe3O4@C Composites with Tunable Magneto-dielectric Properties for High-Performance Microwave Absorption

Development of microwave absorbing materials (MAMs) with strong and broadband absorption at thin thickness to address electromagnetic radiation and interference is still a huge challenge. Herein, bimetallic oxalate rod-derived NiFe/Fe3O4@carbon rods (NiFe/Fe3O4@CRs) composites as MAMs were structured by a facile coprecipitation followed by a carbothermal reduction process. The multiple interfaces existing in the composite can enhance the dielectric loss, and the rod structure can decrease the density of the NiFe/Fe3O4@carbon. The composite shows excellent microwave absorption properties. The minimum reflection loss (RL) value reaches −44.9 dB at an absorber thickness of 2.2 mm, and the efficient absorption bandwidth (RL ≤ −10 dB) is 5.1 GHz with a small thickness of only 1.58 mm. The high-performance microwave absorption mechanisms of the as-prepared NiFe/Fe3O4@CRs composites were mainly attributed to the synergistic of impedance matching, magnetic loss, and electrical loss. This work opens up a new prospect for developing high-performance microwave absorbers.