Exploring the Potential of Ag_1–xNi_x/RGO Nanocomposites for Spintronic Application

Increasing the demand of miniaturized devices, the research on lightweight and ultrathin layered material, particularly on graphene, has grown rapidly. Modification in pristine graphene is highly desirable to attain a finite band gap and magnetic properties to ensure its applicability in spintronic devices. We present here the study of electronic transport and magnetic properties of Ag 1– x Ni x nanoparticles (NPs) decorated on reduced graphene oxide (RGO) nanosheets. A combination of Hummer’s and reflux methods has been used to synthesize nanocomposites of 2–12 nm Ag 1– x Ni x (0 ≤ x ≤ 1) NPs anchored on the RGO sheet. Crystallinity and alloy formation have been confirmed by electron microscopies, X-ray diffraction, and X-ray photoelectron spectroscopy techniques. Raman spectra reveal the presence of a significant amount of defects and the occurrence of charge transfer from RGO to the NPs. The temperature dependence of electrical resistivity studies revealed that the nanocomposites are disordered semiconductors that follow the thermally assisted band conduction mechanism. Electron paramagnetic resonance spectra suggest that all of the samples in the whole x range (0 ≤ x ≤ 1) are ferromagnetic to some extent. DC magnetization results also substantiate the electron paramagnetic resonance results. The 300 K saturation magnetic moments obey a qualitatively negative linear variation with the amount of charge transfer, indicating that the charge transfer has an influence on the nanocomposite magnetism.