Enhanced asymmetric giant magneto-impedance effect and linearity in sandwich FePd/FINEMET/FePd composite ribbons

The FePd/FINEMET/FePd composite ribbons with sandwich structure were designed by magnetron sputtering. The morphology, magnetic properties and asymmetric giant magneto-impedance (AGMI) effect of FePd/FINEMET/FePd composite ribbons show that the sandwich structure can significantly improve the GMI effect of FINEMET ribbon with a homogeneous structure. Results have demonstrated that the magnetic dipole interaction between the FePd layer and the FINEMET ribbon makes the FePd/FINEMET/FePd composite ribbons obtain a larger GMI effect at low frequencies. The maximum GMI ratio of FePd/FINEMET/FePd composite ribbons reaches 51 %, which is 2.2 times that of bare FINEMET ribbon. The asymmetry degree of GMI curves is up to 85 %. It has the ability to significantly enhance the GMI effect, linearity and reduced the characteristic frequency of composite materials. The experimental results can be explained by the magnetic dipole interaction model. It is a profound significance in the development of a magnetic sensor that can increase the GMI ratio and the linearity.