Analysis of Fe–Ni Thin Films Using the Phenomenological Theory of Electrodeposition

Abstract

Fe–Ni thin films electrodeposited using rectangular pulse voltages over a megahertz frequency range were investigated through scanning electron microscopy-energy dispersive X-ray spectroscopy and Xray diffraction. The Ni content of the Fe–Ni thin films increased with the cathode potential; further, it significantly changed at resonant frequencies when the cathode potential was equal to the Fe or Ni potential barrier, and became constant, which was consistent with the phenomenological theory of electrodeposition. The Fe and Ni potential barriers were determined to be 1.48 and 2.22 V, respectively. The Fe–Ni thin films comprised a body-centred cubic crystal structure, namely, α-Fe, and an amorphous structure FeNi0.832 phase (corresponding to the stoichiometric molar ratio of Fe–Ni thin films containing 29.8 at% Ni). The Fe–Ni films had smooth surfaces, which indicated that they were formed by layer-by-layer growth and not by island growth.