Enhanced giant magnetoimpedance effect in FINEMET/TiO₂ composite ribbons

In order to study the influence of semiconductors on the magnetic properties and giant magnetoimpedance effect of FINEMET ribbon, titanium dioxide coating layer with different thickness was sputtered onto the free surface of the FINEMET ribbon by RF magnetron sputtering to prepare the FINEMET/TiO₂ composite ribbons. The morphology, magnetic properties, and giant magnetoimpedance of the FINEMET/TiO₂ composite ribbons were analyzed. The results show that the GMI ratio of composite ribbons first increases and then decreases with the increase of TiO₂ layer thickness (0 ~ 150 nm). When the thickness of TiO₂ thin film is 100 nm, the GMI ratio reaches the maximum 57.3%, which indicates that a certain thickness of TiO₂ thin film can significantly improve the GMI effect. The result can be explained by the combined result of electromagnetic interaction and stress between TiO₂ thin film and the FINEMET ribbon.