Superparamagnetic Cu2+ substituted Mn–MgFe2O4 powders prepared through co-precipitation strategy: structural, microstructure and magnetic properties

Abstract

Manganese magnesium ferrites Mn x Mg1−x Fe2O4 nanopowders (x = 0.2, 0.4, 0.5, 0.6, 0.8 molar ratios) with have been purposefully fabricated using a co-precipitation strategy. The manipulation of the synthesis conditions such as annealing temperature, annealing time, Mn2+ ion molar ratio and Cu2+ ion substituted Mg2+ ion (Mn0.5Mg0.5−z Cu z Fe2O4 with z = 0.1, 0.2 and 0.3) on the crystal structure, microstructure and the magnetic properties was considered using X-ray diffraction, scanning electron microscopy and vibrating sample magnetometer, respectively. The results demonstrated that well crystalline single cubic spinel Mn x Mg1−x Fe2O4 phase was acquired at annealing temperature 1200 °C for time 2 h at pH value 10 using sodium carbonate as a base. The crystallite size, lattice parameter (a) and the unit cell volume were predestined to increase as the annealing temperature as well as the annealing time were increased. Remarkably, Mn content was found to impact on the microstructure of the formed Mn x Mg1−x Fe2O4 nanopowders. Evidently, the produced powders were evinced a well-defined triangle-like structure with high homogeneity by increasing Mn concentration up to 0.8 molar ratio. The magnetic properties were sensitive to annealing temperature, annealing time as well as Mn2+ ion molar ratio and Cu2+ ion content. The saturation magnetization of Cu2+ ion substituted Mn0.5Mg0.5−z Cu z Fe2O4 ferrite powders was continuously increased with an increase in the Cu2+ ion concentration at annealing temperature 1200 °C for 2 h. Finally, high saturation magnetization (M s = ~ 54.2 emu/g) was achieved for the ferrite composition Mn0.8Mg0.2Fe2O4 phase formed at annealing temperature 1200 °C for 2 h.