Soft magnetic and high-frequency properties of FeCoB–SiO2 granular films deposited on flexible substrates

Abstract A series of FeCoB–SiO 2 granular films were deposited on Kapton flexible substrates by magnetron co-sputtering technique at room temperature. All films are amorphous with granular morphology. The coercivity in the easy axis ( H ce ) and the resistivity ( ρ ) decrease with the decrease of the Ar pressure, but they decrease with the increase of the film thickness. The granular films deposited at low Ar pressure exhibit obvious in-plane uniaxial magnetic anisotropy. Excellent soft magnetic properties with the H ce as low as 1.57 Oe was obtained in the 500 nm films deposited at 0.3 Pa. In addition, high ρ (∼3.5 mΩ cm), relatively high complex permeability ( μ ′ = 152.8 at low frequency and μ max ″ = 221.2 ) and ferromagnetic resonance frequency ( f r  ∼ 3.61 GHz) were simultaneously obtained.