Effect of formation of heterostructure of SrAl4Fe8O19/RGO/PVDF on the microwave absorption properties of the composite

Abstract

Radar absorbing materials (RAM) are of strategic importance to shield the targets from getting detected. The wave impedance matching at shield/air interface is an essential condition to absorb most of the incoming radiation which depends on the combination of permittivity, permeability and conductivity of the various components in the composite. Here, we report fabrication of a novel RAM through one port chemical reduction of graphene oxide (GO) in presence of magnetic inclusion of nano-strontium aluminium ferrite SrAl4Fe8O19 (SAF) to make ternary composite films in Poly (Vinylidene) Fluoride (PVDF). Two concentrations with varying ratio of RGO: SAF, 1:1 (RGOSAF11) and 1:2 (RGOSAF21) in PVDF were prepared. The films were tested for RAM properties in transmission line in X-band (8–12 GHz). Morphology using Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) and Elemental analysis using Energy Dispersive X-Ray Analysis (EDAX) revealed that there was more non-uniformity in the dispersion as well as elemental composition in RGOSAF11 compared to RGOSAF21. This was also reflected in the magnetic studies using vibrating sample magnetometer (VSM) and Magnetic Force Microscopy (MFM). RGO plays a crucial role in not only providing the conductive paths in the EM wave absorption but also in the magnetic domain communication of magnetic entities within the RGO network. This further facilitates the effective trapping of incoming radiation and therefore exhibited shielding effectiveness of more than 40 dB. Study of dielectric properties suggests that this optimized ratio of RGO and SAF in the composite provides perfect opportunity for various effects like interfacial polarization and scattering centres which are responsible for the improved absorption properties. Such material can be an impressive absorption block in emerging EMI shielding technology.