The effect of SiO₂ interlayer on magnetic interactions in multilayer composites ribbons

This article studies the influence of dipole interactions on the magnetic properties. Specifically, FINEMET/SiO₂ and FINEMET/SiO₂/Fe₂₀Ni₈₀ composite ribbons were prepared by magnetron sputtering. During the manufacturing process, the Fe₂₀Ni₈₀ film with a fixed thickness of 260 nm and the FINEMET ribbon were separated by the SiO₂ layer, and the SiO₂ layer thickness could be adjusted within a range of 0–150 nm. This configuration enabled the exchange coupling gradually reduced with the SiO₂ layer thickness increased, allowing dipole interactions to become the dominant factor. This study not only excludes the influence of the SiO₂ in the composite ribbons but analyzes the effect of the exchange couple and dipole interactions for the GMI, respectively. The experimental results show the GMI ratio decreases initially and then increases with the thickness of SiO₂, where the optimization of GMI ratio was explored in FINEMET/Fe₂₀Ni₈₀ ribbons. On the other hand, the minimum peak field was shown with the SiO₂ thickness of 5 nm. Furthermore, the results also elucidate that both dipole interactions and exchange couple have affected the peak field of GMI, which could be used for the design of multilayer composite ribbons with better performance. Thus, the analysis we showed in this work is thought to be valuable in revealing the mechanism of multilayer composite ribbons for future sensing applications.