# Graphene and Iron Reinforced Polymer Composite Electromagnetic Shielding Applications: A Review
## 4 Graphene-Based Composites
### Graphene@Iron Composites
#### 4.1.2 Interpretation of Graphene@Iron Composites Articles
The results showed a better absorption performance due to the impedance matching ability of Fe\({}_{3}\)O\({}_{4}\)@f-GNPs compared to dielectric f-GNPs and magnetic Fe\({}_{3}\)O\({}_{4}\), with a reflection loss of \(-\)25 dB at 10 GHz frequency when having 2 mm sample thickness and 2.4 GHz (below \(-\)10 dB) effective absorption bandwidth. Moreover, the absorption and total efficiencies were 32 dB and 25 dB respectively, when the Fe\({}_{3}\)O\({}_{4}\)@f-GNPs exhibited shielding efficiency properties with 232 nm Fe\({}_{3}\)O\({}_{4}\) in the X band. [PERSON] et al. [86] investigated the EMI shielding effectiveness of epoxy nanocomposites containing Fe\({}_{3}\)O\({}_{4}\) nanoparticles coated graphene nanoplatelets, where by using a co-precipitation technique and a solvent-less approach, hybrid nanostructures were synthesized in situ. The results showed the high EMI shielding effectiveness of Fe\({}_{3}\)O\({}_{4}\)@GCNP compared to other samples having equivalent loading of GNP and Fe\({}_{3}\)O\({}_{4}\). The sample containing a 1:3 ratio of Fe\({}_{3}\)O\({}_{4}\):GNP hybrid with 1 mm thickness reduced incident wave power up to 89% with EMI shielding effectiveness of 9.6 dB. [PERSON] et al. [87] fabricated a multilayer sandwich structure from graphene nanoplates (GNPs), ferric metal-organic frameworks (MOFs) (MIL-88B)-derived magnetic carbon-based materials (C-MIL-88B) via a filtration assisted self-assembly method. With the insertion of Fe\({}_{3}\)O\({}_{4}\)-C, C-MIL-88B/GNP adequate results in terms of magnetization and conductivity were shown, where the composite film consisting of five layers with the thickness of 0.12 mm showed effective EMI shielding with the value of 28 dB in the X-band frequency range with 86% of power coefficient absorption. [PERSON] et al. [88] synthesized porous graphene (PG) with Fe\({}_{3}\)O\({}_{4}\) via in situ growth. It was revealed that PG-Fe\({}_{3}\)O\({}_{4}\) provides excellent microwave absorption where the reflection loss came as \(-\)53 dB at 5.4 GHz frequency. PG which is formed by structure modification is important in achieving the results and showed better performance when get compared with the ordinary graphene. Graphene oxide (GO) was synthesized with carbonyl iron particles (CIP) by the wet stirring process. The shielding effectiveness of the composite was examined within the range of 0-18 GHz where the maximum reflection loss of \(-\)56.4 dB was achieved while keeping the thickness as 1.9 mm. The composite is proposed to be used in X-band as well as Ku-band [89]. Ag@Fe\({}_{3}\)O\({}_{4}\) was synthesized with reduced graphene oxide by using the solvothermal method. In the testing range (2-18 GHz) the maximum reflection loss came as \(-\)40.05 dB at 11.9 GHz [90]. In another study, Fe\({}_{3}\)O\({}_{4}\)@C/RGO was synthesized using the solvothermal method where the reflection loss of \(-\)59.23 dB was achieved at 6.24 GHz within the frequency range of 2-18 GHz while keeping the thickness at 3.57 mm [91]. [PERSON] et al. [92] synthesized natural rubber with magnetic iron oxide and reduced graphene oxide, forming an NRMG composite. The shielding effectiveness of 26.4 dB was achieved within the testing range of X-band while keeping the sample thickness as 1.6 mm. [PERSON] et al. [92] synthesized graphene and Fe\({}_{3}\)O\({}_{4}\) with carbon (C) nanoparticles to form a shielding composite. The reflection loss of \(-\)55.05 dB was achieved within the 2-18 GHz frequency range. [PERSON] et al. [93] synthesized magnetic graphene (G) with Fe\({}_{3}\)O\({}_{4}\) (F) hybrid material via the hydrothermal method. The shielding effectiveness was tested within the 2-18 GHz frequency range. While keeping the sample thickness as 1.9 mm, shielding effectiveness of 20 dB was achieved. [PERSON] et al. [94] Ni\({}_{0.5}\)Co\({}_{0.5}\)Fe\({}_{2}\)O\({}_{4}\)/graphene via a hydrothermal method to form a shielding composite, where it was tested within the range of 0.58-1.19 GHz. A reflection loss of \(-\)30.92 dB was achieved at 0.84 GHz with 4 mm thickness. [PERSON] et al.