Ankit JainSachin Kumar GodaraRajshree B. JotaniaBishakha RaySuwarna DatarCharanjeet Singh2025-08-062025-08-062025-06http://doi.org/10.1016/j.ceramint.2025.06.028https://gnanaganga.alliance.edu.in/handle/123456789/8479In this study, Co2+ and Ce3+ substituted BaCoxCexFe12-2xO19 hexaferrites, combined with polyaniline (PANI), were synthesized via the sol-gel combustion method to explore their structural, dielectric, magnetic, and microwave absorption properties. Substitution levels (x = 0.0 (XP1), 0.6 (XP2), and 1.0 (XP3)) were investigated, revealing significant modifications in structural and electromagnetic characteristics with increasing Co-Ce doping. Field Emission Scanning Electron Microscopy (FESEM) confirmed a transition from well-separated grains in XP1 to densely packed and fused grains in XP3. Dielectric analysis showed a frequency-dependent decrease in real part of permittivity and imaginary part of permittivity, aligning with Maxwell-Wagner polarization. XP1 exhibited the highest real part of permittivity (ε′) of 12,791.13 at low frequencies, while XP3 demonstrated reduced imaginary part of permittivity, attributed to enhanced grain boundary effects. Magnetic measurements revealed a reduction in saturation magnetization (Ms) from 45.92 emu/g in XP1 to 33.42 emu/g in XP3, reflecting the impact of Co2+ and Ce3+ doping on Fe3+ superexchange interactions. Impedance spectroscopy highlighted significant grain boundary effects, with XP3 exhibiting the highest grain boundary resistance, while XP1 showed superior conductivity. Microwave absorption analysis demonstrated effective reflection loss (REL), with XP3 achieving the highest REL of −33.29 dB at 11.48 GHz at 9.9 mm thickness, attributed to superior impedance matching (|Zin| = 364.37 Ω). XP1 displayed effective broadband absorption, with a maximum REL of −36.34 dB at 10.05 GHz and broader frequency coverage. These results establish Co-Ce substituted BaCoxCexFe12-2xO19/PANI composites as promising materials for electromagnetic interference (EMI) shielding and broadband microwave absorption applications. © 2025 Elsevier Ltd and Techna Group S.r.l.enComplex PermeabilityComplex PermittivityElectricalHysteresis LoopsReflection Lossjournal-article