Soft magnetic property and high-frequency permeability of [Fe80Ni20–O/TiO2]n multilayer thin films

• Fe80Ni20–O/TiO2n multilayer thin films were fabricated by magnetron sputtering.
• In-plane magnetic anisotropy can be adjusted only by the thickness of TiO2 layer.
• Excellent high-frequency characteristics in gigahertz range can be obtained.
• Promote the application of the multilayer thin films in the GHz range.

Multilayer thin films with excellent magnetic property and high-frequency permeability possess a significant position in electromagnetic miniaturization devices applied in GHz range. In this work, by controlling the alternately magnetron sputtering time at room temperature, we fabricated [Fe80Ni20–O/TiO2]n multilayer thin films with different TiO2 interlayer thicknesses (t = 0.25–4 nm) and fixed Fe80Ni20–O layer thickness without applying inducing magnetic field. The static and dynamic magnetic properties of these films were investigated and evident in-plane uniaxial magnetic anisotropy field can be adjusted in a broad range only by changing the thickness of the TiO2 interlayer. When the t increases gradually from 0.25 to 4 nm, the resistivity and in-plane uniaxial magnetic anisotropy field increase monotonically. In particular, by controlling the thickness of each TiO2 interlayer to an optimized value, good soft magnetic property and high-frequency performances in GHz range have been observed.