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

Abstract

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 Fe3O4/(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 Ms 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 (RLmin) reached −49.3 dB at 4.15 GHz. As microwave absorption materials, the DF/alloys composites are extremely promising and competitive.