Two-dimensional heterostructures of graphene (Gr) and metal/semiconducting elements convey new direction in electronic devices. They can be useful for spintronics because of small spin orbit interaction of Gr as a non-magnetic metal host with promising electrochemical stability. In this paper, we demonstrate one-step fabrication of magnetic Ni-particles entrapped within Gr-flakes based on simultaneous electrochemical exfoliation/deposition procedure by two-electrode system using platinum as the cathode electrode and a graphite foil as the anode electrode. The final product is an air stable hybrid element including Gr flakes hosting magnetic Ni-nano-crystals showing superparamagnetic-like response and room temperature giant magnetoresistance (GMR) effect at small magnetic field range. The GMR effect is originated from spin scattering through ferromagnetic/non-magnetic nature of Ni/Gr heterostructure and interpreted based on a phenomenological spin transport model. Our work benefits from XRD, XPS, Raman, TEM, FTIR and VSM measurements We addressed that how our results can be used for rapid manufacturing of magnetic Gr for low field magneto resistive elements and potential printed spintronic devices.

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In this study, Au/Pd(II) core-shell colloidal nanoparticles (NPs) were prepared by pulsed laser (Nd:YAG, λ = 1064 nm) ablation synthesis in solution (LASiS) of gold target in PdCl 2 solution of different concentrations. From X-ray diffraction, metallic Au, PdO, or PdCl 2 crystal phases were obtained in this process. Surface plasmon resonance investigations, by means of UV−vis spectrophotometer, revealed damping of Au peak by increasing PdCl 2 concentration. Transmission electron microscope showed the bimetallic particles are spherical core Au NPs covered by a Pd(II) shell whose thickness is dependent on PdCl 2 concentration. X-ray photoelectron spectroscopy was used for surface chemical analysis. On the basis of the results from the previously described measurements, a mechanism for Au/Pd(II) core-shell formation was given.

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.

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