Interconnected magnetic carbon@NixCo(1-x)Fe(2)O(4) nanospheres with core-shell structure: An efficient and thin electromagnetic wave absorber

摘要

The applications of cobalt ferrite and nickel ferrite composite materials on electromagnetic (EM) wave absorption are the research hotspot currently. However, the systematical comparison study between these two ferrites composites have rarely been carried out. Thus, the EM wave absorption performance of interconnected carbon@NixCo1-xFe2O4 composites with core-shell structures were investigated comprehensively in this work. A series of magnetic nanospheres including NiFe2O4, cobalt-doped nickel ferrite, nickel-cobalt ferrite, nickel-doped cobalt ferrite and CoFe2O4 were synthesized firstly, and then uniformly encapsulation by carbon rendered the corresponding C@NixCo1-xFe2O4 composites nano spheres. Synthesis reactions involved for C@NixCo1-xFe2O4 formation were investigated in detail, and afterwards their magnetic behavior, EM wave absorption performance and absorbing mechanism were thoroughly explored and analyzed. Results show that when nickel is dominant element and cobalt is doping element (Ni0.75Co0.25Fe2O4), the composite nanosphere exhibits optimum EM wave absorption performance. When the sample thickness is just 1.9 mm, its RLmin value can reach-51 dB, and the corresponding EAB width is 3.3 GHz. The synthesized C@Ni0.75Co0.25Fe2O4 can be qualified as an efficient and thin electromagnetic wave absorber, which is mainly attributed to its special structure, fair electromagnetic matching and impedance matching. (C) 2021 Elsevier Inc. All rights reserved.