Influence of MWCNTs on the formation, structure and magnetic properties of magnetite

Solvothermal method was utilized to prepare iron oxide powders and iron oxide-MWCNT nanocomposites using iron chloride III, ethylene glycol and sodium acetate. The influence of MWCNTs on the formation, structure and magnetic properties of magnetite was investigated. The contraction of lattice parameter was occurred in the magnetite-MWCNT nanocomposite, which indicated that there is a competition between the reduction of Fe3+ to Fe2+ by the decomposition of ethylene glycol assisted by sodium acetate, and the oxidation of Fe2+ to Fe3+ by MWCNTs leading to the vacancies. The amount of these vacancies represents the degree of phase transition from near magnetite to near maghemite. Magnetic properties of the product were investigated by vibrating sample magnetometer. Saturation magnetization of magnetite was 91 emu/g that is about the bulk magnetization. The observed magnetic moments per formula unit, estimated by saturation magnetization are in good agreement with magnetic moments per formula unit calculated from iron ion distribution among the two interstitial (tetrahedral and octahedral) sites. The results were confirmed by FESEM, TEM and UV-vis analyzes.