Effect of amorphous SiO2 matrix on structural and magnetic properties of Cu0.6Co0.4Fe2O4/SiO2 nanocomposites

This study presents the structural and magnetic characterization of alpha Cu0.6Co0.4Fe2O4/(100-alpha)SiO2 (alpha = 0, 25, 50, 75 and 100%) nanocomposites prepared by sol-gel method, followed by thermal treatment at 200, 500, 800 and 1200 degrees C. The SiO2 matrix was found to be amorphous. At low ferrite contents, the obtained Cu-Co ferrite is unpurified by crystalline CoO, while at high ferrite contents single-phase Cu-Co ferrite is obtained. The particle sizes increase from 30 to 120 nm with increasing ferrite content embedded in the SiO2 matrix, while the crystallinity increases at higher thermal treatment temperature. The atomic force microscopy revealed the morphology of the Cu0.6Co0.4Fe2O4/SiO2 nanocomposites. For samples treated at 200 and 500 degrees C, the specific surface area increases and the crystallinity decreases with increasing SiO2 content. For all samples, the surface area decreases with the increasing annealing temperature. The SiO2 matrix is diamagnetic and does not show hysteresis curve. The saturation magnetization and remanent magnetization improved, while the coercivity and magnetic anisotropy decreased with increasing Cu-Co ferrite content embedded in SiO2 matrix. (C) 2020 Elsevier B.V. All rights reserved.