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Description
The magnetite Fe$_3$O$_4$ nanoparticles have been synthesized successfully by hydrothermal method in the egg white solution. The egg white solution was used as a surfactant and it can also reduce impurity phase in samples. This work aims to study the influence of different reaction temperatures (160-220 $^o$C) on the structure and magnetic properties of the synthesized Fe$_3$O$_4$ nanoparticles. The results of X-ray diffraction (XRD) and selected area electron diffraction (SAED) indicate that the synthesized Fe$_3$O$_4$ nanoparticles have the inverse cubic spinel structure without the presence of any other phase. The particle sizes of samples are in the range of ∼10–50 nm as revealed by transmission electron microscopy (TEM). X-ray absorption near edge structure (XANES) spectra show the oxidation state of Fe$^{3+}$ and Fe$^{2+}$ in the samples. The hysteresis loops of the Fe$_3$O$_4$ nanoparticles exhibit superparamagnetic behavior at room temperature for all conditions. The saturation magnetization increases with increasing reaction temperature except at 220 $^o$C.
