Electrochemical Synthesis of Nanocrystalline Ni0.5Zn0.5Fe2O4 Thin Film from Aqueous Sulfate Bath

Nanocrystalline nickel-zinc ferrites Ni0.5Zn0.5Fe2O4 thin films have been synthesized via the electrodeposition-anodization from the aqueous sulfate bath. The electrodeposited (Ni-Zn)Fe2 alloy was anodized in aqueous 1？M KOH solution to form the corresponding hydroxides which annealed at different temperatures ranging from 800 to 1000°C for various periods from 1 to 4？h, to get the required ferrite. SEM micrograph of the formed ferrite particles, annealed at 1000°C for 4？h appeared as the octahedral-like structure. A good saturation magnetization of 28.2？emu/g was achieved for Ni0.5Zn0.5Fe2O4 thin film produced after the aforementioned conditions. The kinetic studies of the crystallization of Ni0.5Zn0.5Fe2O4 films appeared to be first-order reaction and the activation energy was found to be 10.5？k Joule/mole. 1. Introduction In recent years, soft magnetic Ni-Zn ferrite films with good magnetic properties, high resistivity, and low coercivity have critical need for high-frequency applications such as RF broad “band choke band,” planar inductors, magnetic sensors, transformers cores, rod antennas, microwaves devices, and telecommunication [1–6]. Therefore, numerous deposition techniques are used for synthesis of required ferrites thin films. They include ferrite plating [7], chemical vapor deposition [8], sputtering [7], dip coating [9], spray pyrolysis [10], and pulsed laser deposition [11] processes. The main difficulties of these methods are that the substrate during or after deposition must be kept at high temperatures, which imposes restrictions on the selection of the substrate material [7]. Also, some of these processes require expensive equipment for a high degree of control. Furthermore, on sintering, the possibility of nonreproducible products and toxic gases are produced [12]. To avoid the problems arising from the high-temperature processes, room temperature synthesis of metal ferrites thin films using electrochemical deposition methods has attracted much attention [13, 14]. In comparison, the electrodeposition technique provides not only the possibility of using low synthesis temperature but also low cost of starting materials and a high purity of the product yield [15–17]. In our previous work, Ni-Zn ferrites thin films have been synthesized via the electrodeposition from ethylene glycol nonaqueous solution [13]. The results obtained indicate the production of NixZn1-x Fe2O4. A high saturation magnetization (48？emu/g) is achieved for Ni0.5Zn0.5Fe2O4 phase. The activation energy of its crystallization is found to be 32？kJ/mol. The present