Microstructure and magnetoimpedance studies of NiFe films electrodeposited on ITO substrate: Experiments and simulations

Abstract

Structure and magnetoimpedance (MI) properties of Permalloy films electrodeposited on Indium Tin Oxide (ITO) coated on glass substrate have been investigated. Microstructure and magnetic measurements confirm the composition and formation of single phase films with varying thickness. The MI values increased from 2.8% to 50%, while the frequency at which maximum MI is observed shifted to lower frequency when thickness of the NiFe film is increased. Present results show that MI is not only weak but also exhibits a sign change in the lower frequency range. It is shown that the magnetoinductive component is dominant at lower frequencies. Thickness and frequency dependence of MI values are compared with numerically calculated results on the basis of Maxwell’s and Landau- Lifshitz equations. It is found that the thickness and effective conductivity of the film play a significant role in variation of MI values. We have attempted to extract the relative magnetic permeability (μr), the damping factor (α), the angle between the equilibrium state of magnetization and easy axis (θ) and the magnetic anisotropy field (Hk) by fitting the experimental MI data to the standard equations. Experimental results are consistent with the physical parameters obtained from the phenomenological model. The relative permeability values extracted from the MI data corroborate well with magnetic measurements of literature.