Nanocrystalline spinel ferrite (MFe2O4, M = Ni, Co, Mn, Mg, Zn) powders prepared by a simple aloe vera plant-extracted solution hydrothermal route

Nanocrystalline spinel ferrite MFe2O4 (M = Ni, Co, Mn, Mg, Zn) powders were synthesized by a novel hydrothermal method using Fe(acac)3, M(acac)3 (M = Ni, Co, Mn, Mg, Zn) and aloe vera plant extracted solution. The X-ray diffraction and selected-area electron diffraction results indicate that the synthesized nanocrystalline have only spinel structure without the presence of other phase impurities. The crystal structure and morphology of the spinel ferrite powders, as revealed by TEM, show that the NiFe2O4 and CoFe2O4 samples contain nanoparticles, whereas the MnFe2O4 and MgFe2O4 samples consist of many nanoplatelets and nanoparticles. Interestingly, the ZnFe2O4 sample contains plate-like structure of networked nanocrystalline particles. Room temperature magnetization results show a ferromagnetic behavior of the CoFe2O4, MnFe2O4 and MgFe2O4 samples, whereas the samples of NiFe2O4 and ZnFe2O4 exhibit a superparamagnetic behavior.

Graphical abstractThis figure shows the specific magnetization curves of the as-prepared MFe2O4 (M = Ni, Co, Mn, Mg, Zn) powders obtained from room temperature VSM measurement. These curves are typical for a soft magnetic material and indicate hysteresis ferromagnetism in the field ranges of ±500 Oe, ±1000 Oe, and ±2000 Oe for the CoFe2O4, MgFe2O4 and MnFe2O4 respectively, whereas the samples of NiFe2O4 and ZnFe2O4 show a superparamagnetic behavior.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Nanocrystalline MFe2O4 powders were synthesized by a novel hydrothermal method. ► Metal acetylacetonates and aloe vera plant-extracted solution are used. ► This biosynthetic route is very simple and provides high-yield oxide nanomaterials. ► XRD and TEM results indicate that the prepared samples have only spinel structure. ► The maximum Ms of 68.9 emu/g at 10 kOe were observed for the samples of MnFe2O4.