A low temperature synthesis of MnFe2O4 nanocrystals by microwave-assisted ball-milling

In this paper, well-dispersed MnFe2O4 nanocrystals with high saturation magnetization were successfully prepared at a low temperature (below 100 °C) by a one step process through microwave-assisted ball milling in aqueous solution. The obtained nanocrystals were characterized by XRD, TEM, VSM. A lattice structure transition at a constant-temperature between tetragonal and cubic Mn3O4 intermediate product phases was observed during the reaction process. By the comparison of the as-milled products obtained with and without microwave-assistance, it was found that the coupling effect of ball-milling and microwave played a key role in the lattice transition and synthesis of MnFe2O4 nanocrystals.

• Well-ordered MnFe2O4 nanoparticles were directly obtained without subsequent calcinations. • The synthesized MnFe2O4 nanoparticle has a high saturation magnetization. • The approach is microwave-assisted ball milling technology for obtained nanoparticle. • A interesting reciprocating Mn3O4 isothermal phase transition was observed.