Structural analysis and magnetic-microwave absorption properties of natural mineral-derived silica-coated magnetite nanocomposites

• Published in: Journal of magnetism and magnetic materials 2022-08, Vol.556, p.169458, Article 169458
• Main Authors: Husain, H., Dewi, R., Adi, W.A., Taryana, Y., Pratapa, S.
• Format: Article
• Language: English
• Subjects: Chemical reactions; Coercivity; Diffraction patterns; Dipole moments; Electric dipoles; Electron micrographs; Fourier transforms; Infrared spectra; Iron oxides; Lattice parameters; Magnetic dipoles; Magnetic properties; Magnetic saturation; Magnetite; Microwave absorption; Nanocomposites; Nanoparticles; Natural resources; Remanence; Silica-coated; Silicon dioxide; Structural analysis; Zircon
• ISSN: 0304-8853; 1873-4766
• DOI: 10.1016/j.jmmm.2022.169458

[Display omitted] •Synthesis of silica-coated magnetite by employing local natural resources.•Synchrotron XRD and XANES for crystal and electronic structure analysis of silica-coated magnetite.•Effect of SiO2 coating on magnetic and microwave absorption properties of Fe3O4 nanoparticles.•Combined dielectric and magnetic losses for enhanced microwave absorption properties. Herein, a green synthesis method to prepare silica-coated magnetite nanocomposites by employing ironstone (an Indonesian natural resource) and an industrial by-product of zircon sand purification is reported. The X-ray diffraction pattern confirmed the formation of the magnetite phase, with an increased lattice constant after the coating process. The absorbance peaks of Fourier transform infrared spectra and the clear boundary in high-resolution transmission electron micrographs suggested that no chemical reaction was involved between Fe3O4 and SiO2. Silica coating caused a decrease in magnetic saturation and initial susceptibility and an increase in the coercivity, remanence, and domain magnetic size of composites. The microwave absorption peaks for SiO2 and Fe3O4 nanoparticles were observed at approximately 10.00 and 11.00 GHz, respectively. Fe3O4/SiO2 nanocomposites exhibited both absorption peaks with improved absorption and a tunable frequency. Furthermore, the combination of Fe3O4 as a magnetic and SiO2 as a dielectric material provided an advantage in adjusting the direction of the magnetic dipole moment and electric dipole polarization for specific applications.