Synthesis of Fe-Co Nanobars using Sodium Sulfite Assisted Polyol Process and their Structural and Magnetic Studies G. Suresh 1 , P. Saravanan 2 and D. Rajan Babu 1,+ 1 School of Advanced Sciences, VIT University, Vellore-632 014, India 2 Defence Metallurgical Research Laboratory, Hyderabad-500 058, India + drajanbabu@vit.ac.in (corresponding author) Submitted: November 15, 2010; revised: January 6, 2011; accepted: January 18, 2011 Keywords: Alloy, Polyol, Sodium sulfite, Magnetic nanobars Abstract. We report the synthesis of soft magnetic Fe-Co nanobars by an improved polyol process using cetyltrimethylammonium bromide (CTAB) as stabilizer. The synthesized samples were studied by using Transmission Electron Microscopy. The Fe-Co nanoparticles were characterized by X-ray diffraction, UV-Vis spectroscopy, Fourier transform infrared spectroscopy and Vibrating Sample Magnetometer. The Fe-Co nanobars showed prominent UV-VIS absorption at 371 nm. This report discusses the effect of sodium sulfite and CTAB on the synthesis of Fe-Co nanoparticles. Introduction Owing to their superior properties, nanomaterials have sparked substantial curiosity among the research community. Especially, the synthesis of ultrafine magnetic nanoparticles with tailored properties is vital for a variety of applications such as ultra high density data storage [1], ferrofluids [2], magnetic resonance imaging [3], magnetic hyperthermia treatment [4], drug delivery [5], magnetic refrigeration [6] and other applications. Among the binary ferromagnetic alloys, body centered cubic (bcc) Fe-Co intermetallic alloys are well known for their unique combination of high saturation magnetization, high Curie temperature, low magnetocrystalline anisotropy, soft magnetic material and good strength. They are ideally suited for applications requiring high flux densities [7,8]. However, the chemical instability of Fe-Co nanoparticles has made the synthesis extremely challenging. Synthesizing magnetic nanoparticles with narrow size distribution is a significant task for advanced applications. A variety of chemical methods such as thermal decomposition [9], sonochemical synthesis [10], co-precipitation [11] and polyol process [12, 13] have been reported for the synthesis of nanoparticles. Among the various methods, the polyol process is believed to be one of the most appropriate, because of the possibility to kinetically control the experimental conditions and to easily scale up. The polyol process was first reported by Figlarz et al. [14]. This method has an experimental difficulty in that the precursors in ethylene glycol had to be refluxed at boiling point for a longer period. This method was later modified by Viau et al. [15] through the addition of sodium hydroxide which enhanced the reduction rate and reduced the reaction time. Kodama et al. [13] synthesized Fe- Co dice using polyol process and they were able to synthesize submicron to 35 nm sized cubes by varying the temperature and metal ion concentration. Sodium sulfite is well known to bind oxygen and thus to suppress oxidation in the reaction medium [16,17]. In the present work, we modified the process by replacing sodium hydroxide by sodium sulfite and studied its effect on the synthesis of Fe-Co nanoparticles. To the best of our knowledge no attempt has been made to synthesize Fe-Co nanoparticles by sodium sulfite assisted polyol process. Here we report the synthesis of Fe-Co nanoparticles by the polyol process and also its structural, magnetic properties. Journal of Nano Research Vol. 15 (2011) pp 21-28 Online available since 2011/Sep/13 at www.scientific.net © (2011) Trans Tech Publications, Switzerland doi:10.4028/www.scientific.net/JNanoR.15.21 All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP, www.ttp.net. (ID: 117.211.91.3-14/09/11,06:58:19)