Structural and magnetic studies of Mg substituted cobalt composite oxide catalyst Co1− x Mg x Fe2O4

The article synthesized the Co_1−xMg_xFe₂O₄ sample of single phase spinel structure with sol-gel auto-combustion. The lattice parameter increases, the X-ray density and average crystal sized decrease with an increase in the Magnesium content. The average crystallite size increases with an increase in the calcinating temperature. The ferrimagnetic behaviour of all samples is confirmed by room temperature Mössbauer spectra, and the magnetic hyperfine field decrease with an increase in Mg substitution, which can be attributed to the decrease of the A-B super-exchange interaction. The calcining temperature influences the magnetic hyperfine field and the distribution of Fe³⁺ ions at the tetrahedral A site and the octahedral B site. The saturation magnetization and coercivity have significant change with increasing Mg²⁺ ions, the decrease in the coercivity suggests that the sample towards soft magnetic material transformation. Magnesium substituted for Cobalt both having preference to occupy B sites (octahedral sites) reduces. Besides that increased particle size with Mg substitution causes increased distance, and reduces magnetic moment of the B sublattice.