Umama Saeed, Muhammad Azhar Khan, Asif Jamil, Marcus Vinicius Castegnaro, Abdul Majeed, Mohammed A. Amin, Shagufta Gulbadan, Zaki I. Zaki, M. Irfan, Mohamed E. Khalifa, Majid Niaz Akhtar
BaCr2O4 nanocrystallites with Mg substitution (0.0 ≤ x ≤ 0.75) were synthesized using the sol-gel auto-combustion technique. After preparation, all samples were sintered at 700 °C for 5 h to achieve the Ba1-xMgxCr2O4 phase. A comprehensive analysis of the material's properties was performed using XRD for structural insights, FTIR for molecular bonding information, and UV–Vis spectroscopy for optical characterization. Additionally, Raman spectroscopy was utilized to determine molecular structure, while dielectric measurements assessed electrical and microwave absorption characteristics. XRD measurements confirmed a pure orthorhombic structure (space group Pnma, No. 62) with crystallite sizes ranging from 25 to 42 nm. The replacement of Mg2+ at both the A and B sites was confirmed using FTIR spectroscopy. FTIR analysis of Ba1−xMgxCr2O4 nanoparticles showed structural modifications with Mg substitution, influencing metal-oxygen bond strength and lattice stability. Vibrational modes show variations in bond lengths and force constants. The material exhibits strong absorption bands between 400 and 600 nm. Raman spectroscopy detects six active Raman modes attributed to metal-oxygen and Cr-O vibrations. The dielectric properties demonstrate a decrease in dielectric constant as frequency decreases, and conduction dominates as frequency increases, aligning with Wagner and Koop's theory. Notably, the material exhibits high dielectric losses and higher Q-values, making it suitable for applications in the microwave range, such as absorption and shielding of electromagnetic interference. © 2025 Elsevier Ltd and Techna Group S.r.l.
Institute of Physics, The Islamia University of Bahawalpur, Bahawalpur, 63100, Pakistan; Institute of Physics, Federal University of Rio Grande do Sul (UFRGS), Brazil; Department of Physics, The Islamia University of Bahawalpur, Bahawalnagar Campus, Bahawalnagar, 62301, Pakistan; Department of Chemistry, College of Science, Taif University, P.O. Box 11099, Taif, 21944, Saudi Arabia; Mechanical and Industrial Engineering Department, Engineering Faculty, Universitas Negeri Malang, 65145, Indonesia
