Mixed-metal carbonates as precursors for the synthesis of nanocrystalline Mn–Zn ferrites

A mixed Mn–Zn–Fe carbonate was prepared by precipitation of metal ions with ammonium carbonate and control of pH=7. Nanocrystalline Mn–Zn ferrite powders were synthesized by thermal decomposition of the carbonate precursor at 500 °C in air. The mean crystallite size of the ferrite particles is 14 nm with a specific surface of 74 m2/g. The magnetization at 5 K of the Mn–Zn ferrite powders (66 emu/g) is smaller than the saturation magnetization of the bulk material. Hysteresis loop measurements indicate ferrimagnetic behavior at 5 and 298 K with a small coercivity at room temperature.