Electrodeposited NiFe films for electronic applications: structure and magnetic properties

Abstract

Pulse and pulse-reverse current modes were used to electrodeposit Ni–Fe nanostructured films. Correlation between modes, chemical composition, structural features, and magnetic properties was observed. Iron content decrease was observed both with transition from pulse to pulse current electrodeposition mode (from 42.1 to 27.5 at.%) and with reverse pulse prolongation (from 27.5 to 17.4 at.%). It opens broad perspectives for control of the Fe/Ni ratio in wide region in permalloy films by the varying of the electrodeposition regimes. XRD data showed that Fe solid solution in Ni was formed in all the films. All samples were single phase. Pulse-reverse samples have rougher surface (R_q from 14.1 to 36.5 nm) with convex grains in comparison with pulse sample, which has smoother surface (R_q of 4.1 nm) and undistinguishable grains. Higher grain size uniformity with reverse pulse duration increase was observed. All the Ni–Fe films have a significant magnetic anisotropy observed from the hysteresis loops, measured in plane and out of plane. The easy magnetization axis is located in the plane of the film for all the samples. Coercive force H_c of the Ni–Fe films is ∼ 2–12 times greater during the sample in-plane investigations in comparison with sample out-of-plane investigations. This confirms possibility to obtain the highly anisotropy nanostructured film by varying the electrodeposition regimes. Such kind of films can be successfully applied for magnetic field sensors and for electromagnetic shields.