The improvement of radar absorption performance in MnxFe3–xO4/PANI/AC nanocomposites by manipulating the composition of 3d transition metal elements

Radar-absorbing materials (RAMs) have been extensively employed, particularly in national security stealth technologies. Even though various novel RAMs have been invented, iron oxides still attract tremendous attention due to their distinctive properties that are suitable for radar absorption applications. However, some development should still be carried out to improve the feasibility of iron oxides as RAMs. In this study, iron oxides-based RAMs were developed by manipulating the composition of 3 d metal transition elements, Fe and Mn, which mainly influence the radar absorption performance. We also use a compositing strategy by combining this iron oxide with conductive and dielectric polymer materials to form Mn _xFe _3–xO ₄/PANI (polyaniline)/AC (activated carbon) nanocomposites. The nanocomposites were synthesized using the coprecipitation method with x = 0–1.2 variation. The RAMs functioned in the X-band frequency range (approximately 7–13 GHz) with a thickness of 2 mm to 5 mm. The Mn _xFe _3–xO ₄/PANI/AC nanocomposites were successfully fabricated by various examinations. The Mn ²⁺ ion was incorporated into Fe ₃O ₄, while the nanocomposites exhibited sphere-like morphologies constructed from Mn _xFe _3–xO ₄, AC, and PANI having aggregates, granules, and chains forms, respectively. Moreover, the nanocomposite sample exhibited superparamagnetic properties, with the saturation magnetization decreasing with the increase in the Mn ²⁺. Interestingly, the Mn _xFe _3–xO ₄/PANI/AC nanocomposites with x = 1.2 showed a high radar absorption performance with a reflection loss of –42 dB at 9.3 GHz, which mainly attributed to the magnetic loss mechanism and, thus, makes the obtained nanocomposite very potential for radar absorption applications. We believe our findings could pave the way for the realization of iron oxide-based RAMs for radar absorption applications.