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We have synthesized r-GO-ATA-Fe2O3 nanocomposites and studied their microstructural and electromagnetic properties for future possible magnetic resonance imaging for biomedical application. X-ray diffraction, transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and X-ray absorption near edge spectroscopy were used to study the structural and electronic properties, while a superconducting quantum interface device magnetometer was used for investigating the magnetic behavior of the nanocomposites. The nanocomposites have been found to reduce the graphitic structure of GO due to the substitution of carbon/oxygen and/or iron nanoparticles. Conversely, the electrical conductivity of nanocomposites is found to be high due to the formation of Fe—C/Fe—O bonds in the structure of the nanocomposites. The composites also exhibit superparamagnetic features as observed from the M-H hysteresis loop with saturation magnetization of ≈0.1 emu/g at 1.8 K temperature. The results, in general, suggest possible applicability of r-GO/Fe2O3 nanocomposites as an effective multifunctional platform for magnetic resonance imaging in biomedical applications.

There has been rapid growth in research activities on the potential of graphene oxide/Au (GO:Au) composite for different applications. The GO:Au composite has been widely explored in applications such as biomedicine, electrochemical biosensors, optical limiters, and organic dye degradation. The increased interest in GO:Au for these applications is the consequence of harvesting the electronic bonding structure that is due to the formation of sp 3 C C clusters from defected sp 2 C═C and attachment of Au atoms onto the C═C carbon matrix.The defection of the sp 2 cluster of GO can be achieved by the method of improved synthesis and functionalization with Au surfactants. The current review explores an overview of the different synthesis techniques for producing GO:Au composites, which is an important factor in controlling the particle and size distribution of the composites. The electronic, electrical, and magnetic properties of GO:Au composites are covered as it relates to photochemical, memristive, and biomedical imaging applications. The low coercivity and remanence are consistent with superparamagnetic behavior. Although, GO:Aunanocomposite (NC) are widely explored for biomedicine and drug delivery applications, future applications of the composite can be useful for magnetic resonance imaging owing to the superparamagnetic behavior. The future possibilities of GO:Au-NP are promising in the field of bioimaging and electronic devices. The electrical property of GO:Au-NC can be fused with its electrochemical property for supercapacitor applications. In some cases, GO:Au-NC is used as an anchor material with conducting polymers to enhance the supercapacitor properties. Furthermore, the synthesis of mono-disperse few-layer graphene is still challenging owing to economic cost and the graphite exfoliation process. The review of GO:Au composite from a material physics perspective aims to elucidate the current trends as well the future possibilities offered by the composite for various promising applications. Novelty Statement• This review focused on the graphene oxide-gold nanocomposite which is an outstanding composite material for different applications.

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Silicon-oxide-nanoparticle (SiO2-NP) heteroatoms were decorated/deposited onto multiwall carbon nanotube (MWCNT) surface to tune the properties of MWCNTs for electronic and magnetic applications. To achieve this objective, SiO2-NPs and MWCNTs were prepared and suspended together into toluene and heated at <100 °C for the formation of MWCNTs/SiO2-NP nanocomposites. A change in the microstructure, electronic, electrical, and magnetic behaviors of MWCNT nanocomposites decorated/deposited with silicon content was investigated using different techniques, viz., scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy for structural, compositional, and electronic structure, while current–voltage was used for electrical properties and field-dependent magnetization and electron spin resonance techniques were used for magnetic properties. The results indicated that SiO2-NPs adhered onto MWCNTs, resulting in variation in the material conductivity with the Si-NP content. The coercivity of MWCNT nanocomposites adhered with 1.5 atom % Si-NPs (HC@40 K = 689 Oe) is higher than that of those adhered with 5.75 atom % Si-NPs (HC@40 K = 357 Oe). In general, the results provide information about the possibilities of tuning the electronic, electrical, and magnetic properties of MWCNTs by adherence of SiO2-NPs onto them. This tuning of material properties could be useful for different electronic and magnetic device applications.

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