Zahra dastjerdi - Department of Materials Engineering, M.Sc., University of Sistan and Baluchestan, Zahedan, Iran
Mahdi Shafiee Afarani - Department of Materials Engineering , Associate Professor, Faculty of Engineering, University of Sistan andBaluchestan, Zahedan, Iran,
Amir masud Aarabi - Department of Inorganic Pigments and Glazes, Assistant Professor Institute for Color Science and Technology(ICST), Tehran, Iran
Ebrahim Ghasemi - Department of Inorganic Pigments and Glazes, Associate Professor, Institute for Color Science and Technology(ICST), Tehran, Iran

In the present work, magnetite nano particles were synthesized by precipitation method in thepresence of polyoxyethilen (۸۰), sorbitan monoleate (Tween ۸۰), surface modifier under N۲atmosphere, using Iron (II) chloride (FeCl۲) and Iron (III) chloride (FeCl۳) as starting materials.Then samples were dispersed in water media to investigate the stability. Structure, microstructure, magnetic and optical properties were studied using X-ray diffraction (XRD), scanningelectron microscopy (SEM), vibrating sample magnetometer (VSM), UV-Vis spectrometrytechniques. Results showed that synthesis in the presence of surface modifier increased theuniformity of spherical nano magnetite particles. Moreover, VSM results at room temperatureshowed that the samples were superparamagnet without hysteresis loop. Band gap of sampleswere estimated as ۲.۸ eV which was ۰.۱ eV, larger than for bulk samples. Nano particles weresynthesized in the presence of ۰.۵ g/l Tween ۸۰ showed the best stability in aqueous media.

Fe۳O۴, magnetic nano fluid, precipitation, surface modifier, stability