Synthesis and characterization of Co0.8Fe2.2O4 nano ferrite

Co0.8Fe2.2O4 nano ferrite has been synthesized by sol gel auto-combustion method. X-ray diffraction (XRD) and Mossbauer spectroscopy were used to characterize the synthesized as burnt and thermally annealed (600 degrees C for 3 hours) samples. Both XRD and Mossbauer measurements confirm the formation of spinel phase with Scherrer's grain diameter (D-s) approximate to 37 nm. Presence of alpha-Fe and, Fe2O3 was also observed. Thermal annealing induced decrease of rho(xrd) (from 5267.9 to 5262.7 Kg/m(3)) for the annealed samples is ascribable to the fact that, increase of unit cell volume overtakes the increase in mass of the unit cell. Comparison of dry gel and thermally annealed sample shows that in dry gel, B site is more populated with Fe ions, whereas thermal annealing leads to migration of Co from A to B site with simultaneous migration of Fe from B to A site, thus dropping the Neel magnetic moment. Bond angle values clearly reveal that thermal annealing leads to strengthening of B-O-B interaction with simultaneous wreaking of A-O-B, and, A-O-A interaction.