Magnetite/Mn-ferrite nanocomposite with improved magnetic properties

摘要

Magnetic nanocomposites can show enhanced properties compared to their single phase counterparts. Novel soft ferrite Fe_3O_4/soft ferrite MnFe_2O_4 nanocomposite, as well as pure MnFe_2O_4 and Fe_3O_4 for the sake of comparison, were synthesized by co-precipitation method. The spinel type of structure (space group Fd(3)m) of the samples was confirmed by XRPD and SAED. Samples are composed of spherical particles with size in the range 5-15 nm Nanocomposite (92 wt%) MnFe_2O_4/(8 wt%) Fe_3O_4 exert single phase like magnetic behavior. Saturation magnetization (M_s) of Fe_3O_4/MnFe_2O_4 is 26% greater than M_s of MnFe_2O_4 and even 50% than M_s of Fe_3O_4. At the same time coercivity field of the nanocomposite is twice less value (H_c= 180 Oe) than in binary ferrites (H_c=360 Oe). Magnetization enhancement and softening in Magnetite/Mn-ferrite is discussed related to particle interactions among two different ferrites and intrinsic properties of nanoparticles. Tailoring phase ratio and synthesis conditions can be a tool for tuning magnetic properties of nanocomposites.