Electromagnetic Response Characteristics Of Fe₃O₄ And Their Composite Nanostructure

Nano-sized magnetite materials have drawn considerable attention for their special physical and chemical characteristics, such as quantum size effect, mesoscopic effect and quantum-tunnel effect. Ferroferric oxide is an important magnetic material, and is widely applied in the biomedicine, gas sensing, photocatalysis, optical modulation, magnetic memory.The focus of the research is the electromagnetic wave absorption properties of ferroferric oxide in this article. The contents of the research show as follows:1. Controlled synthesis and electromagnetic wave response of porous Fe3O4 nanoparticles with various morphologiePorous Fe3O4 nanoparticles with sphere-like, cube-like and walnuts-like morphologies were obtained by hydrothermal method. Morphologies of porous Fe3O4 nanoparticles were controlled by the additives and the reaction temperature. The microstructure of three Fe3O4 nanoparticles were determined by Scanning Electron Microscope,Transmission Electron Microscope,X-ray Diffraction and X-ray photoelectron spectroscopy.40 wt% of the nanospheres, nanocubes and nanowalnuts were added into wax matrix for measuring the electromagnetic parameters of the composites. The reflection loss values were all less than-10 dB at the different frequency region for the three composites with the thickness of 2-5 mm.2. Controlled synthesis and electromagnetic wave response of Fe3O4/ZnO core/shell nanorodsβ-FeOOH nanorods were fabricated by a hydrothermal method.β-FeOOH nanorods were dispersed in ethylenediamine and Zn (AC)2 aqueous solution. Fe2O3/ZnO core/shell nanorods were synthesized by hydrothermal method. Fe2O3/ ZnO core/shell nanorods were deoxided under the Ar/H2 flow. Fe3O4/ZnO core/shell nanorods were obtained. The microstructure of Fe3O4/ZnO core/shell nanorods were measured and determined by Scanning Electron Microscope,Transmission Electron Microscope,X-ray Diffraction and X-ray photoelectron spectroscopy.50 wt% of Fe3O4/ZnO core/shell nanorods were added into wax matrix for measuring the electromagnetic parameters of the composite to measure the electromagnetic wave absorption properties of Fe3O4/ZnO core/shell nanorods. The reflection loss reaches-30 dB for the absorber with the thickness in only 1.5 mm, and up to-35 dB for the absorbe with the thickness in 2 mm.3. Controlled synthesis and electromagnetic wave response of Fe3O4/TiO2 core/shell nanotube.Fe2O3 nanotubes were synthesized by a hydrothermal method. Fe2O3 nanotubes was dispersed into distilled water under vigorously stirring. The Ti(SO4)2 aqueous solution was added into the suspension. Then, Fe2O3/TiO2 core/shell nanotubes were obtained. Fe2O3/TiO2 core/shell nanotubes were deoxided under the Ar/H2 flow. Fe3O4/TiO2 core/shell nanotubes were obtained. The characterization of Fe3O4/TiO2 core/shell nanotubes were measured and determined by Scanning Electron Microscope,Transmission Electron Microscope,X-ray Diffraction and X-ray photoelectron spectroscopy.50 wt% of Fe3O4/TiO2 core/shell nanotubes were added into wax matrix for measuring the electromagnetic parameters of the composite to measure the electromagnetic wave absorption properties of Fe3O4/TiO2 core/shell nanotubes. The reflection loss values were all less than-10 dB at the different frequency region for the the composite with the thickness of 2-5 mm.