Abstract
Iron-manganese oxide (MnxFe1-xO) nanoplates were prepared by the thermal decomposition method. Irregular development of crystalline phases was observed with the increase of annealing temperature. Magnetic properties are in accordance with their respective crystalline phases, and the selective magnetic evolution from their rich magnetism of MnxFe1-O-x and MnFe2O4 is achieved by controlling the annealing conditions. Rock-salt structure of MnxFe1-O-x (space group Fm3m) is observed in as-synthesized nanoplates, while MnFe2O4 and MnxFe1-xO with significant magnetic interactions between them are observed at 380 degrees C. In nanoplates annealed at 450 degrees C, soft ferrites of Mn0.48Fe2.52O4 with MnxFe1-xO are observed. It is assumed that the differential and early development of crystalline phase of MnxFe1-xO and the inhomogeneous cation mixing between Mn and Fe cause this rather extraordinary magnetic development. In particular, the prone nature of divalent metal oxides to cation vacancy and the prolonged annealing time of 15 h which enables ordering are also thought to contribute to these irregularities.