Construction and boosted electromagnetic wave absorption performance of porous aggregates of multi-element doped Fe3O4/(Fe, Co, Ni, Cu) alloy with magnetic/magnetic heterostructure

Pure magnetic materials always exhibit mediocre microwave absorption performance due to the poor impedance matching and negligible dielectric loss capability. In this study, a novel porous aggregates of multi-element doped Fe 3 O 4 /(Fe, Co, Ni, Cu) alloys (denoted as DF/alloys) composite which is composed of magnetic/magnetic heterostructure with excellent microwave absorption performance were prepared. By reducing part of the ferrimagnetic spinel into ferromagnetic alloy, the saturation magnetization M s was enlarged which is beneficial to exceeding the Snoek′s limit, and the magnetic loss capability was further enhanced significantly. Furthermore, the abundant heterogeneous interfaces in the DF/alloys composites have greatly improved the dielectric loss capability and balanced the complex permittivity and the complex permeability, and achieved superior impedance matching of the magnetic/magnetic heterogeneous DF/alloys composites. When the loading ratio (DF/alloys to paraffin mass ratio) was only 30 wt%, the widest effective absorption bandwidth ( EAB ) reached 5.58 GHz (3.2 mm). when the loading ratio was up to 50 wt%, the widest EAB (6.4 GHz) was achieved at 2.0 mm and the minimum reflection loss ( RL min ) reached −49.3 dB at 4.15 GHz. As microwave absorption materials, the DF/alloys composites are extremely promising and competitive.