Structural, magnetic, and electromagnetic wave absorption properties of AC/CB–Fe2O3 nanocomposites in the Ku-Band

The increasing demand for efficient microwave absorbers to curtail electromagnetic interference (EMI) and reduce radar cross-sections, indispensable for electronic shielding and stealth technologies, propels the pursuit of materials with excellent absorption, lightweight properties, and broadband performance. This study investigates the magnetic and Ku-band microwave performance of ferrite nanoparticles (α-Fe2O3) blended with carbon-based materials, Activated Carbon (AC), and Carbon Black (CB), synthesized via high-energy ball milling (HEBM) and heat treatment. Fe2O3 nanoparticles were milled for 5, 7, and 9 h to evaluate the milling time on structural and magnetic properties. Blended Fe2O3/AC and Fe2O3/CB composites were subjected to 1-h heat treatment at 200 °C. X-ray diffraction (XRD) analysis confirmed phase formation and crystallinity, while Vibrating Sample Magnetometer (VSM) characterization evaluated magnetic properties. Increasing milling time reduced crystallite size and coercivity (Hc), enhancing soft magnetic behaviour. The result obtained shows that the sample milled for 9 h exhibited higher saturation (Ms) and remanent magnetization (Mr). The blended Fe₂O₃/AC composite, prepared using 9-h milled Fe₂O₃ and 20% AC, achieved a remarkable reflection loss (RL) of -39.10 dB at 16.95 GHz (Ku-band) for a 2.0 mm thick sample, demonstrating almost complete microwave absorption (99.99%). These findings advance the production of high-performance and lightweight absorbers by linking crystallite refinement, carbon allotrope selection, and electromagnetic response.