Superparamagnetic iron oxide nanoparticles: effect of iron oleate precursors obtained with a simple way Fatmahan Ozel • Hakan Kockar • Seda Beyaz • Oznur Karaagac • Taner Tanrisever Received: 24 January 2013 / Accepted: 26 March 2013 / Published online: 25 April 2013 Ó Springer Science+Business Media New York 2013 Abstract The objective of the study was to investigate the effect of different amounts of iron oleate precursor with different oleic acid amounts on the properties of the syn- thesised nanoparticles by thermal decomposition. The iron oleate precursors which formed from oleic acids in the order of 0.5, 1.0, 1.5 and 2.0 g, and 0.1 g iron powder was prepared under 200 °C seperately, using a facile solvo- thermal method under study. Thermal analysis of iron oleat precursors by a thermogravimetric analysis (TGA) revealed that the different amount of oleic acid was seen to have an impact on the thermal properties of iron oleat complexes. During the synthesis of nanoparticles, iron oleate complex in 1-hexadecane kept refluxing for 3 h under air atmo- sphere resulting in the formation of nanoparticles. The fourier transform infrared spectra measurements and the TGA analysis disclosed that nanoparticles were coated with oleic acid. To the X-ray diffraction patterns, all samples are iron oxide nanocrystals and their crystal sizes increased from 6.4 to 9.8 nm with decreasing oleic acid. Also, the sizes of nanoparticles were found to be in same range as confirmed with the surface observation by a transmission electron microscope. The magnetic properties obtained from a vibrating sample magnetometer revealed that all nanoparticles are superparamagnetic at room tem- perature. Also, their saturation magnetizations were up to 33.2 emu/g. It is seen that the nanoparticles are super- paramagnetic with the desired structural and corresponding magnetic properties and therefore, they could be thought to be convenient for biomedical applications as the particles can be transferred to aqueous phase. 1 Introduction Since the novel physical and chemical properties of nanosized particles differ from the bulk materials, they become suitable for broad range of disciplines, including magnetic fluids, data storage, catalysis and bioapplications [1–4]. When the size of nanoparticles is below a critical value, the thermal energy, k B T exceed the magnetic anisotropic energy barrier and consequently nanoparticles become superparamagnetic [2, 5]. Nanoparticles can also be modified with some coating agents, therefore their sizes can be kept with desired values and become soluble in different solvents and avoid agglomeration which makes them preferable for specific applications such as drug delivery, molecular detection, contrast agents in magnetic resonance imaging [6, 7]. Magnetic nanoparticles can be mostly synthesized with several methods such as thermal decomposition [8], co- precipitation [9], microemulsion [10] and hydrothermal synthesis [11]. Among them, the thermal decomposition is one of the most used method and can be addressed to control of size, shape and monodispersity during synthesis of the nanoparticles [2, 12]. Therefore, the method is useful F. Ozel (&) Á H. Kockar Á O. Karaagac Physics Department, Science and Literature Faculty, Balikesir University, Cagis Yerleskesi, 10145 Balikesir, Turkey e-mail: fatmahanzel@hotmail.com H. Kockar e-mail: hkockar@balikesir.edu.tr O. Karaagac e-mail: karaagac@balikesir.edu.tr S. Beyaz Á T. Tanrisever Chemistry Department, Science and Literature Faculty, Balikesir University, Cagis Yerleskesi, 10145 Balikesir, Turkey e-mail: sedacan@balikesir.edu.tr T. Tanrisever e-mail: taner@balikesir.edu.tr 123 J Mater Sci: Mater Electron (2013) 24:3073–3080 DOI 10.1007/s10854-013-1213-3