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

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 Fe2+ or Ni2+ potential barrier, and became constant, which was consistent with the phenomenological theory of electrodeposition. The Fe2+ and Ni2+ 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, alpha-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.

Automated summary

Fe-Ni thin films electrodeposited using rectangular pulse voltages over a megahertz frequency range showed an increase in Ni content with cathode potential and significant changes at resonant frequencies. The Fe-Ni films comprised a body-centred cubic crystal structure alpha-Fe and an amorphous structure FeNi0.832 phase, with smooth surfaces indicating layer-by-layer growth.