  Graphene (Gr), a well-known 2D material, has been under intensive
investigation in the last decade due to its high potential applications in
industry and advanced technological elements. The Gr, while composed with
magnetic materials, has opened new opportunities for further developments of
magnetic based devices. Here, we report a mass production of Gr/Ni composite
powders using electrochemical exfoliation/deposition method with different
magnetic strengths of the final composite material. We applied the magnetic
composite materials in a magnetoimpedance (MI) based sensor and observed
significant enhancement in the MI effect and its field sensitivity. Such
magnetic composites with controlled magnetization strengths are coated on the
MI-ribbon sensor surface and different MI responses are observed. The MI
response of a ribbon coated with a Gr/Ni layer is theoretically determined
based on an electrodynamic model with a qualitative consistency between the
experimental results and the theoretical model. Our comprehensive study can be
applied in high performance functionalized MI based magnetic sensors and
devices.
