High temperature magnetic properties of Co1-xMgxFe2O4 nanoparticles prepared by forced hydrolysis method

Abstract

In this work, we study the effect of Mg2+ nonmagnetic ions on the magnetic properties of cubic Co1-xMgxFe2O4 mixed nanostructured ferrites synthesized by a forced hydrolysis method. Magnetization measurements show that all specimens are superparamagnetic at room temperature, and the saturation magnetization (Ms) decreases with increasing the molar magnesium concentration, being 260 emu/cm3 and 160 emu/cm3 for x = 0.0 and 0.6, respectively. The Curie temperature TC, ∼740 K is determined by means of the inverse of the susceptibility versus temperature and slightly depends on the Mg content. The effective anisotropy constant, (Keff) decreases with substitution of Co2+ ion by nonmagnetic Mg2+ ions in the spinel structure. These results are discussed in terms of interparticle interactions induced by the thermal fluctuations, cation distribution and other imperfections that could increase with temperature.