Method to improve high-frequency magnetic characteristics of Fe₈₀Ni₂₀–O alloy films by introducing low-dose oxygen

In this letter, we propose a method to fabricate Fe₈₀Ni₂₀–O film with improved static and high-frequency, magnetic and electrical properties. Fe₈₀Ni₂₀–O alloy films were prepared by direct current magnetron sputtering at room temperature. The results show that the in-plane uniaxial magnetic anisotropy fields can be adjusted in a broad range by solely adding a very low dose of oxygen into Fe₈₀Ni₂₀ alloy films without applying any inducing field on substrates during deposition. By increasing the oxygen flow ratio from 0.75% to 3%, Fe₈₀Ni₂₀–O alloy films could be achieved with an adjustable ferromagnetic resonance frequency fᵣ (from 2.2 to 5.9GHz), a large saturation magnetization 4πMs (from 16.7 to 15.2kG), and a high resistivity ρ (from 56.7 to 108μΩcm).