Sohail Ahmad, Majid Niaz Akhtar, Sijie Zhang, Fatimah Mohammed A. Alzahrani, Imran Shakir, Muzamil Ahmed Warsi, Poppy Puspitasari, Hao Zhang, Sagr Alamri, Tayba Chudhary, M.S. Al-Buriahi, Muhammad Azhar Khan
The rapid advancement of electronic systems and wireless communication technologies has intensified concerns over electromagnetic interference and environmental electromagnetic pollution. This escalating issue has spurred a critical demand for advanced absorbing materials capable of attenuating EM waves and minimizing both functional disruptions and environmental impact. In this work, Yb3+-doped lithium ferrites with the formula Li0.5Fe2.5-xYbxO4 (x = 0.000-0.100) were synthesized via the sol-gel method and systematically investigated for their structural, optical, magnetic, dielectric, and electromagnetic absorption properties. X-ray diffraction confirmed a cubic spinel phase (Fd-3m), with lattice parameters increasing from 8.446 Å to 8.455 Å as Yb3+concentration increased. The band gap narrows from 2.84 eV to 2.20 eV, indicating enhanced photon absorption due to increased defect states. FTIR and Raman spectroscopy confirmed the presence of characteristic metal oxygen stretching vibrations. Magnetic measurements revealed soft ferrimagnetic behavior, with saturation magnetization decreasing from 59.52 to 54.77 emu/g and coercivity increasing from 72.04 to 93.79 Oe. The dielectric constant decreased with increasing frequency and increased with Yb3+-doping, reflecting enhanced space charge polarization. AC conductivity enhanced with frequency, confirming polaron hopping. The Q-factor and tangent loss indicated strong dielectric relaxation, while the real and imaginary parts of the electric modulus and impedance revealed reduced grain boundary effects and improved electrical response at high frequencies. Remarkably, the x = 0.10 sample achieved an ultra-high reflection loss of −80.1 dB at 14.19 GHz, along with a broader absorption bandwidth, confirming its potential for EMI and radar absorption applications. These results demonstrate the feasibility of tuning multifunctional behavior in Li-ferrites via rare-earth doping for next-generation electronic, magnetic, and microwave technologies. © 2025 Elsevier Ltd and Techna Group S.r.l. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
School of Mechanical Engineering, Guizhou University of Engineering Science (GUES), Guizhou, 551700, China; School of Science, Guizhou University of Engineering Science, Bijie, 551700, China; College of Physics, Sichuan University, Chengdu, 610065, China; Institute of Physics, The Islamia University of Bahawalpur, Bahawalpur, 63100, Pakistan; Mechanical and Industrial Engineering Department, Faculty of Engineering, Universitas Negeri Malang, 65145, Indonesia; Department of Chemistry, College of Science, Princess Nourah bint Abdulrahman University, P .O. Box 84428, Riyadh, 11671, Saudi Arabia; Department of Physics, Faculty of Science, Islamic University of Madina, 42351, Saudi Arabia; School of Chemical Engineering, Guizhou University of Engineering Science, Bijie, 551700, China; Department of Mechanical Engineering, College of Engineering, King Khalid University, Abha, 61421, Saudi Arabia; School of Chemistry, Zhejiang University, Hangzhou, 310027, China; Department of Physics, Sakarya University, Sakarya, Turkey; Center for Engineering and Technology Innovations, King Khalid University, Abha, 61421, Saudi Arabia
