Synthesis and characterization of MoS2/Fe@Fe3O4 nanocomposites exhibiting enhanced microwave absorption performance at normal and oblique incidences

Herein,we attempted to prepare MoS2/Fe@Fe3O4 nanocomposites capable of strongly absorbing broadband incident electromagnetic(EM)radiation and probed the effects of their composition on complex permittivity and permeability at 2-18 GHz.Calculations of normal-incidence reflection losses(RLs)based on EM parameters revealed that the Fe@Fe3O4 to MoS2 mass ratio strongly influenced the absorption peak intensity and bandwidth.Specifically,an RL peak of-31.8 dB@l5.3 GHz and a bandwidth(RL<-lOdB)of4.8 GHz(13.2-18 GHz)were achieved at a thickness of 1.52 mm and a Fe@Fe3O4 to M0S2 mass ratio of 60:40.Further,RL and bandwidth were investigated for oblique incidence,in which case two kinds of EM waves(TE-electric field perpendicular to plane of incidence;TM-electric field in the plane of incidence)were considered.The absorption peaks of TE and TM waves did not exceed-2 0 dB when the incidence angle increased to 3 0,and the bandwidth(R L<-10 dB)reached 4.2 GHz(TE wave)and 4.0 GHz(TM wave)when this angle was further increased to 40.0°and 50.4,respectively.Finally,the mechanism of microwave absorption was discussed in detail.

Herein,we attempted to prepare MoS2/Fe@Fe3 O4 nanocomposites capable of strongly absorbing broadband incident electromagnetic（EM）radiation and probed the effects of their composition on complex permittivity and permeability at 2-18 GHz.Calculations of normal-incidence reflection losses（RLs）based on EM parameters revealed that the Fe@Fe304 to MoS2 mass ratio strongly influenced the absorption peak intensity and bandwidth.Specifically,an RL peak of-31.8 dB@15.3 GHz and a bandwidth（RL<-10 dB）of 4.8 GHz（13.2-18 GHz）were achieved at a thickness of 1.52 mm and a Fe@Fe3 O4 to MoS2 mass ratio of60:40.Further,RL and bandwidth were investigated for oblique incidence,in which case two kinds of EM waves（TE-electric field perpendicular to plane of incidence;TM-electric field in the plane of incidence）were considered.The absorption peaks of TE and TM waves did not exceed-20 dB when the incidence angle increased to 30°,and the bandwidth（RL<-10 dB）reached 4.2 GHz（TE wave）and 4.0 GHz（TM wave）when this angle was further increased to 40.0° and 50.4°,respectively.Finally,the mechanism of microwave absorption was discussed in detail.