R&D: Impact of Cobalt Substitutions on Optical, Magnetic, Dielectric, and Structural, Properties of BaFe11.6-xAl0.4CoxO19 Hexaferrites Prepared by Co-Precipitation Process Followed by Rapid Sonochemical Synthesis

Materials Chemistry and Physics has published an article written by Hafeez Ullah, Institute of Physics, Gomal University, Dera Ismail Khan, 29220, KPK, Pakistan, and Department of Physics, University of Buner, Sowari Buner, 19220 KPK, Pakistan, Gamil A.A.M. Al-Hazmi, Department of Chemistry, College of Science, King Khalid University, P.O.Box 9004, Abha 61413, Saudi Arabia, Raed H. Althomali, Department of Chemistry, College of Science and Humanities in Al-Kharj, Prince Sattam Bin Abdulaziz University, 11942, Al-Kharj, Saudi Arabia, and Sana Ullah Asif, School of Materials and Energy. Yunnan University, Kunming, 650091, PR China.

Abstract: “The dielectric along with magnetic features of hexaferrites could be remarkably improved by cationic substitutions. Therefore, in the current work we synthesized cobalt substituted BaFe_11.6-xAl_0.4Co_xO₁₉ (0 ≤ x ≤ 1.2) hexaferrites via co-precipitation process followed by rapid sonochemical procedure. Structural analysis showed that, as the concentration of Co increased, the lattice-parameters ‘a’, ‘c’, crystallites-size, and volume increased. The SEM micrographs revealed the uniform and homogeneous distributions of particles in all samples. The two strong absorption bands indicated by FTIR analysis confirm the successful formation of M-type hexaferrites. The decreasing trend of optical band gape with cobalt doping is indicated by UV vis spectroscopy analysis. The dielectric-loss(ε”), dissipation factor, and dielectric-constant(ε′), increased as the content of cobalt is raised. The produced M-type hexaferrite exhibits increased AC electrical conductivity with frequency and doping concentration. Non-Debye-type relaxation is suggested by the cole–cole diagrams (Mʹ vs. Mʹʹ) for prepared samples. As Co concentrations increased, the magnetic moments per formula unit(m_B) and saturation magnetization increased up to the optimal doping content of x = 0.9, after that these parameters showing decreasing trend. The magnetic anisotropy constant (K), coercivity (H_c), anisotropy-parameter(B), and anisotropy-field(H_a) were all showing increasing tendency with doping content. The investigations above revealed that Co replaced BaFe_11.6-xAl_0.4Co_xO₁₉ (0≤x ≤ 1.2) hexaferrites will be suitable for use as a permanent magnet, magnetic recording media, and other magnetic applications.“