Synthesis and Magnetic Properties of ZnFe2O4 obtained by mechanochemical assisted low-temperature annealing of mixtures of Zn and Fe Oxalates

The mechanism of formation of zinc ferrite (ZnFe2O4) from ZnC2O4·1.8H2O-2FeIIC2O4·2H2O and ZnC2O4·1.8H2O-Fe2III(C2O4)3·6H2O mixtures is investigated. By combination of TG and XRPD measurements it has been shown that microcrystalline ZnFe2O4 forms from physical mixtures after prolonged annealing at 1000 °C while nanocrystalline ZnFe2O4 powders are produced by mild annealing (1 h at 500 °C in air) of mechanically activated mixtures. The magnetic properties of ZnFe2O4 powders obtained from physical and from milled mixtures are compared.