Magnetic iron oxides nanoparticles obtained by mechanochemical reactions from different solid precursors

In this study, iron oxide nanoparticles (NPs) were successfully prepared from three different reactive systems by using mechanochemical synthesis. The effect of using iron salts with different oxidation state and the addition of metallic Fe to the mixture reactive was investigated. The influence of different mechanochemical treatments times on the structural and magnetic properties of the obtained iron oxide NPs was also studied. Composition, crystal structure and morphology of the nanoparticles were analyzed by XRD, Raman spectroscopy, SEM, TEM and DLS techniques. The obtained crystalline NPs exhibited mean sizes of about 8–10 nm and agglomerate in clusters of about 300 nm. Also, magnetic properties as a function of temperature and applied field were determined for the obtained iron oxide NPs, showing high magnetization in the whole temperature range. The results indicated that the presence of metallic Fe in the starting mixture plays a crucial role in the formation of spinel magnetic phases (magnetite/maghemite). Structural and magnetic results are consistent with the formation of maghemite in the studied samples. [Display omitted] •Iron oxide NPs with high magnetization values are synthesized by a mechanochemical acid-base reaction at room temperature.•The simplicity and efficiency of the method allows obtaining mostly maghemite nanoparticles (with mean size about 8–10 nm).•The role of Fe° is crucial to the reactivity on the studied systems and the properties of the produced iron oxide NPs.