Features of pulse-reverse modes for Ni–Fe nanogranular films electrodeposition: Correlation of structural parameters and MI effect

Abstract

Through pulse-reverse electrodeposition with various reverse durations, the Ni–Fe films were synthesized. The film's structure was different. With an increase in the reverse duration, the average grain size and porosity increased to a certain point. As the reversal duration is increased, the porosity and average grain size decrease. Magnetic anisotropy was revealed through an analysis of magnetic characteristics. In particular, when the magnetic field was perpendicular to the samples, the remnant magnetization increased from 0.3 to 2.3 emu/g. The remnant magnetization varied from 77 to 91 emu/g with a parallel orientation. Research on the magnetoimpedance has revealed that at a frequency of 100 kHz, the magnetoimpedance coefficient is at a minimum due to resonance effects in both directions of the magnetic field. The magnetostatic model can be used to explain the mechanism of change in the magnetoimpedance in the low-frequency range. The magnetoimpedance occurs in the medium frequency range (from 10 kHz to 1 MHz) due to changes in the magnetic permeability caused by the impact of a magnetic field and an increase in current frequency, which modify the depth of the skin layer.With an increase in current frequency passing through the sample, the current density on the near-surface layer becomes non-uniform. This non-uniformity is significantly influenced by microstructure parameters such as porosity, average grain size, and the degree of texturization, all of which contribute to the conductor's impedance. It opens new direction for smart sensors development.