chromium substituted cobalt ferrites by glycine-nitrates process

Chromium substituted cobalt ferrites (CoFe_2–xCr_xO₄, 0 ≤ x ≤ 2) were synthesized through solution combustion method using glycine as fuel, named glycine-nitrates process (GNP). As evidenced by X-ray diffraction data (XRD), single cubic spinel phase was formed for all CoFe_2–xCr_xO₄ (0 ≤ x ≤ 2) series. The cubic lattice parameter (a) decreases with increasing chromium content. Room temperature ⁵⁷Fe Mössbauer spectra revealed the Fe³⁺ and Cr³⁺ site occupancy, the local hyperfine magnetic fields and the substitution of Fe³⁺ by Cr³⁺ in the lattice. Scanning electron microscopy (SEM) showed a refinement of particle size with the increase of Cr³⁺ content. Magnetic measurements from 5 K to 120 K have shown a dropping in the saturation magnetization as the chromium content increases. This behaviour has been explained in terms of substitution of Fe³⁺ by Cr³⁺ in the cubic lattice of cobalt ferrite.