Asymmetric magnetoimpedance effect and dipolar interactions of FINEMET/SiO2/FePd composite ribbons


 The dipolar interactions were investigated through the asymmetric magnetoimpedance in FINEMET/SiO2/FePd composite ribbons. The interface between the hard (FePd layer) and soft (FINEMET ribbon) phases was coherent by SiO2 layer in FINEMET/SiO2/FePd composite ribbons, which effectively induced dipolar interactions. The contribution of dipolar interactions to the bias field (H
 
 b
 ) by asymmetrical giant magnetoimpedance and magnetic properties was analyzed. The results show that H
 
 b
 response decreases with the increase of the SiO2 layer thickness. It indicated that the linear region near-zero field can be tuned by the thickness of SiO2 layer. These results allowed the GMI ratio (58 %) and characteristic frequency (500 kHz) were optimized. The transverse and longitudinal magnetic domain structure of FINEMET ribbon and FePd film were confirmed, respectively. The composite ribbons with high GMI ratio and low frequency can apply in linear magnetic sensors.