Effect of Magnetic Field on NiFe Alloy Electrodeposition Ibro Tabakovic, Steve Riemer, Vladyslav Vas’ko, Victor Sapozhnikov and Mark Kief Seagate Technology, 7801 Computer Avenue, Bloomington, Minnesota 55435 An external applied magnetic field during electrodeposition can alter mass-transport and deposit morphology [1,2]. The effect of a magnetic field on mass transport, resulting in induced convection in solution, is well-established [3]. The aim of the present work is to summarize the results of the experiments obtained during the electrodeposition of NiFe films carried out with and without an applied external magnetic field. Here we studied the effect of a magnetic field on electrochemical mass-transport as well as on the properties of NiFe deposits including elemental composition, magnetics, stress, surface morphology, and structure. The NiFe films were electrodeposited from chloride-based electrolytes containing boric acid, saccharin, and sodium lauryl sulfate as additives. The electrodeposition of NiFe films on Cu seed layers (2000 ) was carried out in two paddle cells (0.66 cycle/sec) of identical geometry. One cell was equipped with an external magnetic field (B=0.1T) applied parallel to the electrode surface and another cell was without an applied magnetic field. The concentrations of electrolytes and additives were exactly the same in both cells. The NiFe films of different thicknesses were electrodeposited at constant current density (5.6 mA/cm 2 ) and pH 2.5. Electrochemistry. In the current plateau region with potentials from –0.7 to –0.9 V vs. SCE where mass- transport of protons limits the current, the effect of the magnetic field is to increase the cathodic current. At more negative potentials, corresponding to metal ion reduction, the enhancement of currents obtained with a magnetic field was also observed. Composition. The average iron content in the NiFe deposits increases with increasing film thickness (0.25-5.0 μm) without an applied magnetic field. Thick films (5 μm) produced with an applied magnetic field showed lower Fe contents than films produced without an applied magnetic field. Magnetic Properties. The magnetic field applied during the electrodeposition of NiFe alloys induced uniaxial anisotropy in the soft magnetic films. The NiFe films obtained without an applied magnetic field showed isotropic magnetic behavior. Stress. Tensile stress (100-180 MPa) is dependent on applied magnetic field. NiFe films produced with an applied magnetic field showed smaller tensile stress. Surface Roughness. The roughness of NiFe films decreases with an increase in NiFe film thickness from 0.05 to 5 μm. The NiFe films obtained in the presence of an applied magnetic field are generally smoother than the films obtained without an applied magnetic field. . Texture. As NiFe films start to grow on Cu seed layer, large (111) texture grains are formed first. With increasing thickness, (200) texture with small grains takes over. The magnetic field exhibits a strong effect by enhancing (200) texture. References 1. T.Z. Fahidy, J. Appl. Electrochem., 13, 553 (1983). 2. R. A. Tacken and L. J. J. Janssen, J. Appl. Electrochem., 25, 1 (1995) 3. C. O’Reilly, G. Hinds and J. M. D. Coey, J. Electrochem Soc., 148, C674 (2001).