Studies on Structural, Magnetic and Thermal Properties of xFe2TiO4-(1−x)Fe3O4 (0≤x≤1) Pseudo-binary System

Abstract The x Fe 2 TiO 4 -(1− x )Fe 3 O 4 pseudo-binary systems (0≤ x ≤1) of ulvospinel component were synthesized by solid-state reaction between ulvospinel Fe 2 TiO 4 precursors and commercial Fe 3 O 4 powders in stochiometric proportions. Crystalline structures were determined by X-ray powder diffraction (XRD) and it was found that the as-obtained titanomagnetites maintain an inverse spinel structure. The lattice parameter a of synthesized titanomagnetite increases linearly with the increase in the ulvospinel component. 57 Fe room temperature Mossbauer spectra were employed to evaluate the magnetic properties and cation distribution. The hyperfine magnetic field is observed to decrease with increasing Fe 2 TiO 4 component. The fraction of Fe 2+ in both tetrahedral and octahedral sites increases with the increase in Ti 4+ content, due to the substitution and reduction of Fe 3+ by Ti 4+ that maintains the charge balance in the spinel structure. For x in the range of 0 ≤ x ≤0.4, the solid solution is ferrimagnetic at room temperature. However, it shows weak ferrimagnetic and paramagnetic behavior for x in the range of 0.4 x ≤0.7. When x >0.70, it only shows paramagnetic behavior, with the appearance of quadrupole doublets in the Mossbauer spectra. Simultaneous differential scanning calorimetry and thermogravimetric analysis (DSC–TGA) studies showed that magnetite is not stable, and thermal decomposition of magnetite occurs with weight losses accompanying with exothermic processes under heat treatment in inert atmosphere.