Synthesis and Characterization of Manganese-copper Spinel Ferrite Powders

Magnetic Mn1-xCuxFe2O4(x=0.2, 0.5, 0.8 and 1.0) nanoparticles were synthesized by single citrate precursor method. The samples were characterized by powder X-ray diffraction, vibrating sample magnetometry and electron paramagnetic resonance(EPR). For samples with a low copper content(x<0.5), the copper ions have a tendency to occupy and substitute the Fe3+ at the tetrahedral(A) sites. For samples with a high copper content(x>0.5), most Cu2+ enter into the octahedral(B) sites. Transfer of Fe3+ from octahedral sites to tetrahedral sites leads to the decrease of the saturation magnetization. Maximum coercivity is observed for CuFe2O4 nanoparticles due to the strengthened magnetic anisotropy arisen from the Jahn-Teller effect of the octahedral copper ions. The dependence of magnetic properties of Mn0.8Cu0.2Fe2O4 nanoparticles on calcination temperature was investigated. The cation distribution in Mn0.8Cu0.2Fe2O4 is sensitive to the calcination temperature.