Sohail Ahmad, Faisal Imtiaz, Hao Zhang, Kamal Mustafa, Majid Niaz Akhtar, Irfan Ali Abro, Fatimah Mohammed A Alzahrani, Sami Ullah, Muzamil Ahmed Warsi, M.S. Al-Buriahi, Imran Shakir
The lightweight, high-absorption properties of microwave materials are crucial for addressing electromagnetic challenges in stealth technology. In the present work, the synthesis of Ce-Ni co-doped Sr0.7Mn0.3Fe12-xCexNixO19 (0.0 ≤ x ≤ 0.5) M-type hexaferrite samples using the sol-gel technique is utilized. This study investigated the potential synergistic effects of rare-earth and transition-metal doping on the morphological, optical, and magnetic properties of these materials. XRD patterns actually show that there are some minor secondary phases (mainly attributed to Fe2O3, CeO2, and NiO2) in the samples at higher doping concentration, with consistent increases in lattice parameters and crystallite size (from 63.14 to 86.20 nm) as the Ce-Ni concentration increased. The grain morphology exhibited irregular to plate-like characteristics under scanning electron microscopy (SEM). XPS research verified the existence of Ce3+/Ce4+ and Ni2+ ions, the manifestation of mixed-valence states of Fe and Mn ions, and a charge-compensation process through lattice distortions. With the increase in Ce-Ni content, the optical properties exhibited enhancement through doping: the band gap diminished from 2.47 to 2.0 eV, the refractive index augmented from 2.54 to 2.72, and electrical conductivity markedly increased from 7.88 to 459.25 S/m, indicating improved optical absorption and photocatalytic capability. Alterations in lattice vibrations and Fe–O bonding configurations were validated using FTIR and Raman spectroscopy. The saturation magnetisation (Ms) decreased as the coercivity (Hc) increased, attributed to magnetic dilution, lattice strain, and modified superexchange interactions. Dielectric studies demonstrated a consistent increase with elevated Ce-Ni content, with frequency-dependent behavior. Maxwell-Wagner interfacial polarization at low frequencies and electronic-ionic polarization at elevated frequencies. AC conductivity was observed in small-polaron hopping devices. A complex impedance study revealed improved low-frequency properties suitable for mitigating electromagnetic interference. Notably, reflection-loss experiments demonstrated outstanding microwave absorption at the ideal composition (x = 0.4), attaining an absorption efficiency of -76.92 dB. Owing to enhanced dielectric, magnetic, and impedance-matching properties, Ce–Ni-doped Sr–Mn M-type hexaferrites represent potential prospects for high-performance microwave absorbers in electromagnetic interference shielding, radar stealth coatings, and telecommunication technology. © 2026 Elsevier B.V.
School of Mechanical Engineering, Guizhou University of Engineering Science, Guizhou, 551700, China; School of Chemical Engineering, Guizhou University of Engineering Science, Bijie, 551700, China; Institute of Physics, Bahauddin Zakariya University, Multan, Pakistan; School of Materials Science and Engineering, Beijing Institute of Technology (BIT), Beijing, 100081, China; Institute of Physics, The Islamia University of Bahawalpur, Bahawalpur, 63100, Pakistan; Mechanical and Industrial Engineering Department, Engineering Faculty, Universitas Negeri Malang, 65145, Indonesia; National Key Laboratory of Science and Technology on Materials under Shock and Impact, Beijing Institute of Technology, Beijing, 100081, China; Department of Chemistry, College of Science, Princess Nourah bint Abdulrahman University, P.O. Box 84428, Riyadh, 11671, Saudi Arabia; Department of Chemistry, College of Science, King Khalid University, Abha, 61421, Saudi Arabia; Department of Physics, Sakarya University, Sakarya, Turkey; Department of Physics, Faculty of Science, Islamic University of Madinah, Madinah, Saudi Arabia; Research Center for Advanced Materials Science (RCAMS), King Khalid University, Abha, 61421, Saudi Arabia
