MnFe2O4

MnFe2O4, commonly known as manganese ferrite, is a ferrimagnetic oxide that adopts the spinel crystal structure. In the inverse spinel arrangement, Fe3+ ions occupy both tetrahedral (A) sites and part of the octahedral (B) sites, while Mn2+ ions occupy octahedral sites alongside Fe3+. The general formula can be written as [Fe3+]A[Mn2+Fe3+]BO4, indicating the cation distribution between tetrahedral and octahedral sublattices. The lattice is cubic, with a typical lattice constant around 8.4 Å.

Magnetic and physical properties: MnFe2O4 is ferrimagnetic at room temperature and its Curie temperature depends on synthesis, particle size, and alloying or doping. It is regarded as a soft magnetic material, often exhibiting relatively low coercivity and moderate saturation magnetization, particularly in nanoparticle or thin-film forms. These magnetic traits, combined with chemical stability, make MnFe2O4 suitable for various applications where magnetic manipulation is advantageous.

Synthesis and forms: MnFe2O4 is synthesized through methods such as co-precipitation, hydrothermal or solvothermal processes, sol-gel techniques, and thermal decomposition of metal precursors. Nanoparticles, nanowires, and thin films of MnFe2O4 are studied to tailor surface area, particle size, and magnetic behavior for specific uses.

Applications: In nanomaterial form, MnFe2O4 is explored for magnetic separation, data storage and high-frequency devices, ferrofluids, and catalysis. It has potential in biomedical imaging as a magnetic resonance imaging (MRI) contrast agent, as well as in drug delivery and environmental remediation as a magnetic adsorbent or catalyst in Fenton-like reactions.

Occurrence and safety: MnFe2O4 is primarily encountered in synthetic materials for research and industrial applications. Handling of nanoparticulate forms requires standard safety practices to minimize inhalation and exposure.