Magnetic carbon: Explicit evidence of ferromagnetism induced by proton irradiation

Esquinazi, P.; Höhne, R.; Han, K.‐H.; Setzer, A.; Spemann, D.; Butz, T.

doi:10.1016/j.carbon.2004.01.026

Cited by 50 publications

(34 citation statements)

References 21 publications

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“…On the other hand, impurities, structural disorder and/or topological defects may tune the amorphous disordered nature to slightly ordered states. [13] Indeed, a FM state in CBM was achieved by proton irradiation, [14] or by adsorbed foreign atoms such as hydrogen [15] and/or oxygen [16]. Ferromagnetism was also observed in graphitic sheets with positive or negative curvatures, [17] i n fullerene-related carbon, [18] in carbon nano-spheres encapsulating silver nanoparticles, [19] and in carbon nano-foam (CNF).…”

Section: Of 19mentioning

confidence: 99%

Peculiar Magnetic Features and Superconductivity in Sulfur Doped Amorphous Carbon

Felner¹

2016

Preprint

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Abstract:We report on magnetic studies of inhomogeneous commercial and synthesized amorphous carbon (a-C) and a-C doped with sulfur (a-CS) powders which exhibit (i) peculiar magnetic behavior and (ii) traces of two superconducting (SC) phase ~ Tc=33 and at 65 K. (i) The temperature dependence of zero-field-cooled (ZFC) curves measured up to room temperature show a well distinguish elusive peaks around 50-80 K, their origin is not yet known. These peaks are totally washed-out in the second ZFC sweeps and in the FC branches as well. As a result, in the vicinity of the peaks, the FC curves lie below the ZFC peaks (FC

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Section: Of 19mentioning

confidence: 99%

Peculiar Magnetic Features and Superconductivity in Sulfur Doped Amorphous Carbon

Felner¹

2016

Preprint

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“…In addition to that, the occurrence of carrier induced FM in GNRs has also been envisaged [7]. Theoretical work suggests the presence of strong ferromagnetic interaction ranging several 10 3 K between the edge-state spins in the zigzag edge that can create carbon only FM [8]. The most recent and outstanding works on these materials showed that the magnetic properties are not exclusively related to the presence of extrinsic magnetic ions but strongly determined by the defects.…”

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Ferromagnetism in Graphene Nanoribbons: Split versus Oxidative Unzipped Ribbons

et al. 2012

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* These authors contributed equally to this workTwo types of graphene nanoribbons: (a) potassium-split graphene nanoribbons (GNRs), and (b) oxidative unzipped and chemically converted graphene nanoribbons (CCGNRs) were investigated for their magnetic properties using the combination of static magnetization and electron spin resonance measurements. The two types of ribbons possess remarkably different magnetic properties. While the low temperature ferromagnet-like feature is observed in both types of ribbons, such room temperature feature persists only in potassium-split ribbons. The GNRs show negative exchange bias, but the CCGNRs exhibit a 'positive exchange bias'. Electron spin resonance measurements infer that the carbon related defects may responsible for the observed magnetic behaviour in both types of ribbons. Furthermore, proton hyperfine coupling strength has been obtained from hyperfine sublevel correlation experiments performed on the GNRs. Electron spin resonance provides no indications for the presence of potassium (cluster) related signals, emphasizing the intrinsic magnetic nature of the ribbons. Our combined experimental results may infer the coexistence of ferromagnetic clusters with anti-ferromagnetic regions leading to disordered magnetic phase. We discuss the origin of the observed contrast in the magnetic behaviours of these two types of ribbons.

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“…[9,10,11,12] Ferromagnetism was also reported in a number of carbon systems. [13,14,15,16,17,18,19,20,21,22,23] Some of these studies have speculated that intrinsic carbon defects could be responsible for the observed magnetic properties. Carbon adatoms on carbon nanotube [24] and carbon substitutional doping in boron nitride nanotube [25] were predicted to induce magnestism in the respective systems.…”

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confidence: 99%

Room-Temperature Ferromagnetism in Carbon-Doped ZnO

et al. 2007

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We report magnetism in carbon doped ZnO. Our first-principles calculations based on density functional theory predicted that carbon substitution for oxygen in ZnO results in a magnetic moment of 1.78 µ B per carbon. The theoretical prediction was confirmed experimentally. Cdoped ZnO films deposited by pulsed laser deposition with various carbon concentrations showed ferromagnetism with Curie temperatures higher than 400 K, and the measured magnetic moment based on the content of carbide in the films (1.5 − 3.0µ B per carbon) is in agreement with the theoretical prediction. The magnetism is due to bonding coupling between Zn ions and doped C atoms. Results of magneto-resistance and abnormal Hall effect show that the doped films are ntype semiconductors with intrinsic ferromagnetism. The carbon doped ZnO could be a promising room temperature dilute magnetic semiconductor (DMS) and our work demonstrates possiblity of produing DMS with non-metal doping.

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Magnetic carbon: Explicit evidence of ferromagnetism induced by proton irradiation

Cited by 50 publications

References 21 publications

Peculiar Magnetic Features and Superconductivity in Sulfur Doped Amorphous Carbon

Peculiar Magnetic Features and Superconductivity in Sulfur Doped Amorphous Carbon

Ferromagnetism in Graphene Nanoribbons: Split versus Oxidative Unzipped Ribbons

Room-Temperature Ferromagnetism in Carbon-Doped ZnO

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