Flowerlike iron oxide nanostructures and their application in microwave absorption

Self-assembled flowerlike α-Fe2O3, Fe3O4 and γ-Fe2O3 were fabricated by a simple calcination procedure. The structure characterization shows that the flowerlike morphology and the size of the nanostructures are perfectly maintained in the conversion of precursor to α-Fe2O3, Fe3O4, and γ-Fe2O3. The complex permittivity and permeability results indicate that the dielectric and magnetic loss of Fe3O4 flower are both higher than those of γ-Fe2O3 flower. In addition, Fe3O4 flower shows a good electromagnetic impedance match and its microwave absorption mainly originates from magnetic loss rather than dielectric loss. An optimal reflection loss of −46.0 dB is found at 3.4 GHz for flowerlike Fe3O4, which indicates that the sample can be used as a highly efficient microwave absorber.