Int. J. Thin Film Sci. Tec. 2 No. 3, 233-243 (2013) 233 @ 2013 NSP Natural Sciences Publishing Cor. International Journal of Thin Films Science and Technology http://dx.doi.org/10/12785/ijtfst/020309 Effects of Diammonium Citrate Concentration on Structural and Magnetic Properties of Nano Structured NiFeWS Alloy Thin Films R. Kannan 1* , S. Ganesan 2 , V.Balasubramanian 3 , M.Rajeswari 4 *1 Department of Physics, KSR College of Engineering, Tiruchengode-637215, Tamil Nadu, India. 2 Department of Physics, Government College of Technology, Coimbatore-641001, Tamil Nadu, India. 3 Department of Physics, Tamilnadu College of Engineering, Karumathampatti, Coimbatore- Tamil Nadu, India. 4 Department of Physics, Government College of Technology, Coimbatore-641001, Tamil Nadu, India. E-mail: kannanarjun13@gmail.com Received: 19 Jul. 2013, Revised: 29 Jul. 2013; Accepted: 19 Aug. 2013 Published online: 1 Sep. 2013 Abstract: Electro deposition of NiFeWS thin films was carried out from diammonium citrate bath at a constant current density (1 A/dm 2 ) and controlled pH of 8 by varying the citrate bath concentration(0.2, 0.3, 0.4, 0.5 mol / lit). Physical properties such as surface morphology, microstructure and magnetic properties such as coercivity, saturation magnetization and magnetic flux density were investigated for electrodeposited NiFeWS soft magnetic thin films. The SEM micrographs of the electrodeposited films from the highly concentrated citrate bath (0.5 mol / lit) have no micro cracks and also the films have more uniform surface morphology. The predominant peaks in X- ray diffraction pattern reveal the crystalline nature of the film and the structure belongs to FCC. From the VSM results of the coated film the various magnetic analysis such as coercivity, saturation magnetization and magnetic flux density are calculated. The hardness and adhesion of the electroplated films were also investigated. Reasons for variation in magnetic properties and structural characteristics were discussed. Keywords: Diammonium citrate, microstructure, concentration, magnetic properties 1. Introduction Electro deposition is a simple and well accepted method for depositing thin films of metals and alloys onto conductive substrates. This method offers several practical advantages over more sophisticated vacuum deposition techniques in terms of cost and growth [1]. The magnetic recording head is a key device for achieving high density magnetic recording, with soft magnetic thin films being used as core materials. For fabricating the magnetic recording head, electro deposition is the most suitable method because with electro deposition it is possible to deposit high aspect ratio films of high thickness [2]. As NiFe based alloy posses high saturation flux density, low coercivity and low magnetostriction, NiFe based alloys are more suitable for MEMS. NiFe based thin films were most commonly fabricated by sputtering technique and electro deposition method [3]. Electro deposition offers several practical