Microwave absorbing properties of iron nanowire at x-band frequencies

Iron nanowires and nanoparticles are fabricated via the reduction of iron salts (FeCl3•6H2O) with or without a parallel magnetic field, respectively. Polyvinyl pyrrolidone was added during the reduction process and formed a thin passive layer to minimize the oxidation. The as-obtained iron nanomaterials were then used as magnetic fillers, added to an epoxy resin, and iron nanoparticle or nanowire composites were prepared. The complex permittivity (ɛ' – jɛ") and permeability (μ' – jμ") of these composites are measured by a cavity perturbation method from 7 to 14 GHz. The iron nanowire composites exhibited superior microwaving absorbing properties compared to iron nanoparticle composites. The optimal absorption peak of iron nanowire composites reached −10.5 dB (>90% power absorption) and −15.5 dB (>97% power absorption) with a thickness of 2 and 3 mm, respectively.