Microstructural and Microwave Electromagnetic Properties of FeCoB-SiO_2 Film on PET Substrate

Microstructural and electromagnetic properties of FeCoB-SiO2 films prepared on PET substrates by radio-frequency sputtering were investigated.The as-deposited FeCoB-SiO2 films are found to be amorphous with an electrical resistivity of 1755.73 μ-.cm and a saturation magnetization of 0.7 T.Because of the existence of non-magnetic matrix resistance to magnetic wall displacement,those FeCoB-SiO2 films have a substantially higher co-ercivity of 13130.205 A/m over that of traditional amorphous magnetic films.Complex permeability μ was meas-ured by a microwave network analyzer using the coaxial transmission technique,and double resonance peaks in microwave magnetic permeability were observed in the frequency range of 3.8-5.0 GHz.This is beneficial for the films to be used as a micro absorber at large bandwidths,resulting in μ'2.5 in the frequency range of 500 MHz-12 GHz and μ''6 for 3.6-8.0 GHz.The experimental results demonstrate that the FeCoB-SiO2 films deposited on flexible substrates have good potential for high frequency applications.