Frequency Dependence of FINEMET/Ni/G Composite Ribbons Coated with As-Grown Graphene Layer via Chemical Vapor Deposition

Enhanced Giant Magneto-Impedance (GMI) effects of composite materials play a crucial role in producing devices with a good soft magnetic property. To improve this soft magnetic property, graphene is introduced to increase the conductivity of composite materials. However, the quality of graphene layers restricts the enhancement of GMI effects. There are few reports on the direct growth of graphene on Fe_73.5Si_13.5B₉Cu₁Nb₃ (FINEMET). In this paper, the composite ribbons of FINEMET coated with as-grown graphene are prepared by chemical vapor deposition (CVD), which is much better than previous results obtained by methods such as the transfer method or electroless plating in quality. The Ni layer, with good magnetic conductivity, is induced to the FINEMET as an auxiliary layer by the magnetron sputtering method for high-quality graphene-layer growth due to its high carbon dissolution rate. The results show that the growth temperature of the as-grown graphene layer on the FINEMET with the best GMI ratio could reach as high as 560 °C. Moreover, it was found that an Ni layer thickness of 300 nm has a crucial impact on GMI, with the maximum ratio reaching 76.8%, which is 1.9 times that of an initial bare FINEMET ribbon (39.7%). As a result, the direct growth of graphene layers on FINEMET ribbons by the CVD method is a promising way to light GMI-based devices.