Achieving excellent tunability of magnetic property and microwave absorption performance of FeZn-C core–shell nanoparticles by designing the Fe/Zn ratio

Composition design is vital for the excellent microwave absorption (MA) of core–shell nanoparticles (NPs). In this work, FeZn-C core–shell NPs were synthesized by metal organic chemical vapor deposition with the mixture of zinc (II) acetylacetonate and iron acetylacetonate as precursor. The Fe/Zn ratio of the nanocores could be facilely tuned by adjusting the Zn/Fe ratio in the mixture precursor, and their magnetic behavior could therefore be tuned from super-paramagnetic to ferromagnetic. The Fe/Zn ratio might change the resonance intensity and peak position of the nanoparticle absorbers, and thus be able to tune the attenuation property and improve the thickness matching, leading to double reflection loss peaks and broad effective bandwidth. The optimal reflection loss value of −58.0 dB and effective bandwidth of 8.3 GHz have been achieved from the NP absorbers. These results demonstrated that the introducing of non-magnetic metal atom in C-coated core–shell ferromagnetic NPs endowed them with excellent tunability in magnetic and MA performance, and could also provide a bench for the design of other core–shell NPs.