Direct ESR evidence for magnetic behavior of graphite oxide

Rao, Suchetha; Stesmans, André; Wang, Y.; Chen, Y.

doi:10.1016/j.physe.2011.07.019

Cited by 25 publications

(24 citation statements)

References 26 publications

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“…When our results are consistent with those published by iri¢ et al [7,8] the K-band spectra, published by Rao et al [9] indicate presence of two signals with g ≈ 2. Dierences in so far reported EPR spectra [79] can be explained by the fact that GO is randomly functionalized.…”

Section: Resultssupporting

confidence: 94%

Magnetic Centres in Functionalized Graphene

et al. 2015

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Discussion of the origin of paramagnetic centres observed by electron paramagnetic resonance in graphene oxide (GO) and reduced graphene oxide (rGO) is done on the assumption that GO can be considered as a functionalized graphene. This leads to the conclusion that the narrow signal with g close to 2, observed for GO and thermally reduced GO, is due to paramagnetic centres localized on defects and exchange coupled to conduction electrons. Randomness of graphene modication results in variety of parameters of EPR signals. The broad signals observed in GO and rGO and ascribed to magnetic clusters on the zig-zag edge states indicate that the edge magnetism can be preserved by functionalization.

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Section: Resultssupporting

confidence: 94%

Magnetic Centres in Functionalized Graphene

et al. 2015

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“…Consequently, diamagnetic behavior in graphene-based materials with no d or f electrons is commonly accepted, but diverse magnetism has been reported based on non-trivial mechanisms, such as zigzag edges, defects, vacancies, adatoms, negative Gaussian curvature, and terminal groups at edges. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] The magnetic properties in graphene-based materials have attracted interest because of their potential applications to spintronics for which these properties could incubate high mobility, flexibility, and transparency. Conversely, the magnetic properties of insulating graphene oxides (GO) have not been studied so much, despite versatile applications for these materials in, for example, DNA detectors, high dielectric capacitors, batteries, and so on.…”

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confidence: 99%

Magnetism in graphene oxide induced by epoxy groups

Lee

Seo

Zhu

et al. 2015

Applied Physics Letters

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We have engineered magnetism in graphene oxide. Our approach transforms graphene into a magnetic insulator while maintaining graphene's structure. Fourier transform infrared spectroscopy spectra reveal that graphene oxide has various chemical groups (including epoxy, ketone, hydroxyl, and C-O groups) on its surface. Destroying the epoxy group with heat treatment or chemical treatment diminishes magnetism in the material. Local density approximation calculation results well reproduce the magnetic moments obtained from experiments, and these results indicate that the unpaired spin induced by the presence of epoxy groups is the origin of the magnetism. The calculation results also explain the magnetic properties, which are generated by the interaction between separated magnetic regions and domains. Our results demonstrate tunable magnetism in graphene oxide based on controlling the epoxy group with heat or chemical treatment.

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“…When the size of graphite is reduced to nanodimensions, the localized edge states couple with itinerant electrons, thus leading to a narrow EPR signal, while antiferromagnetism develops when the experiment temperature decreases below 23 Although the magnetic properties of graphene have recently been attracting high attention, due to the graphene's potential application in spintronics devices, there have been only few EPR studies performed on graphene and graphenelike structures. Rao et al 19 observed two EPR signals of rGO: a broad signal at g ¼ 2.0027, which can be attributed to graphitic-like carbon, and a narrower signal at g ¼ 2.0028 associated with carbon radicals. Beckert et al 20 monitored an in situ EPR spectrum to observe free-radical grafting of homo-and copolymers onto functionalized graphene during polymerization.…”

mentioning

confidence: 99%

Comparative electron paramagnetic resonance investigation of reduced graphene oxide and carbon nanotubes with different chemical functionalities for quantum dot attachment

Pham¹,

Krueger²,

Eck³

et al. 2014

Applied Physics Letters

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Electron paramagnetic resonance (EPR) spectroscopy has been applied to different chemically treated reduced graphene oxide (rGO) and multiwalled carbon nanotubes (CNTs). A narrow EPR signal is visible at g = 2.0029 in both GO and CNT-Oxide from carbon-related dangling bonds. EPR signals became broader and of lower intensity after oxygen-containing functionalities were reduced and partially transformed into thiol groups to obtain thiol-functionalized reduced GO (TrGO) and thiol-functionalized CNT (CNT-SH), respectively. Additionally, EPR investigation of CdSe quantum dot-TrGO hybrid material reveals complete quenching of the TrGO EPR signal due to direct chemical attachment and electronic coupling. Our work confirms that EPR is a suitable tool to detect spin density changes in different functionalized nanocarbon materials and can contribute to improved understanding of electronic coupling effects in nanocarbon-nanoparticle hybrid nano-composites promising for various electronic and optoelectronic applications.

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Direct ESR evidence for magnetic behavior of graphite oxide

Cited by 25 publications

References 26 publications

Magnetic Centres in Functionalized Graphene

Magnetic Centres in Functionalized Graphene

Magnetism in graphene oxide induced by epoxy groups

Comparative electron paramagnetic resonance investigation of reduced graphene oxide and carbon nanotubes with different chemical functionalities for quantum dot attachment

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