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 5.9 GHz), a large saturation magnetization 4πMs (from 16.7 to 15.2 kG), and a high resistivity ρ (from 56.7 to 108 μΩ cm).

► Improve the high-frequency magnetic characteristics of Fe80Ni20–O film.
► In-plane uniaxial magnetic anisotropy fields can be adjusted only by adding oxygen.
► Adjustable ferromagnetic resonance frequency in a broad GHz range can be obtained.
► Promote the application of soft magnetic films as the materials for high-frequency.