Fabrication of Co0.5Ni0.5CrxFe2−xO4 materials via sol–gel method and their characterizations

Abstract

Co0.5Ni0.5CrxFe2−xO4 nanoparticles have been designed by the sol–gel auto combustion method, using nitrates of the respective metal ions, and citric acid as the starting materials. The process takes only a few minutes to obtain as-received Cr-substituted Co–Ni ferrite powders. X-ray diffraction (XRD), vibrational sample magnetometer (VSM), transmission electron microscopy (TEM) are utilized in order to study the effect of variation in the Cr3+ substitution and its impact on particle size, lattice constant, specific surface area, cation distribution and magnetic properties. Lattice parameter, particle size found to decrease with increasing Cr3+ content, whereas specific surface area showed increasing trend with the Cr3+ substitution. Cation distribution indicates that the Cr, Co and Ni ions show preference toward octahedral [B] site, whereas Fe occupies both tetrahedral (A) and octahedral [B] sites. Saturation magnetization (MS) decreased from 65.1 to 40.6emu/g with the increase in Cr3+ substitution. However, Coercivity increased from 198 to 365Oe with the Cr3+ substitution.