Fe_3O_4-graphene hybrids: Nanoscale characterization and their enhanced electromagnetic wave absorption in gigahertz range

摘要

Fe_3O_4-graphene hybrid materials have been fabricated by a simple polyol method, and their morphology, chemistry and crystal structure have been characterized at the nanoscale. It is found that each Fe _3O_4 nanoparticles decorated on the graphene has a polycrystalline fcc spinel structure and a uniform chemical phase. Raman spectroscopy, Fourier transform infrared spectroscopy, thermogravimetry/ differential thermal analysis, X-ray diffraction, and transmission electron microscopy suggest that Fe_3O_4 nanoparticles are chemically bonded to the graphene sheets. Electromagnetic wave absorption shows that the material has a reflection loss exceeding -10 dB in 7.5-18 GHz for an absorber thickness of 1.48-3 mm, accompanying a maximum reflection loss value of -30.1 dB at a 1.48-mm matching thickness and 17.2-GHz matching frequency. Theoretic analysis shows that the electromagnetic wave absorption behavior obeys quarter-wave principles. The results suggest that the magnetic Fe _3O_4-graphene hybrids are good candidates for the use as a light-weight electromagnetic wave-absorbing material in X- and K _u-bands.