Title: Ferromagnetism in Graphene Nanoribbons: Split versus Oxidative Unzipped Ribbons
Authors: Rao, S. S ×
Jammalamadaka, S. Narayana
Stesmans, Andre
Moshchalkov, Victor
van Tol, J
Kosynkin, D. V
Higginbotharn-Duque, A
Tour, J. M #
Issue Date: 2012
Publisher: American Chemical Society
Series Title: Nano Letters vol:12 issue:3 pages:1210-1217
Abstract: Two 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 a 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 suggest that the carbon-related defects may be responsible for the observed magnetic behavior in both types of ribbons. Furthermore, information on the proton hyperfine coupling strength has been obtained from hyperfine sublevel correlation experiments performed on the GNRs. Electron spin resonance finds no evidence for the presence of potassium (cluster) related signals, pointing to the intrinsic magnetic nature of the ribbons. Our combined experimental results may indicate the coexistence of ferromagnetic dusters with antiferromagnetic regions leading to disordered magnetic phase. We discuss the possible origin of the observed contrast in the magnetic behaviors of the two types of ribbons studied.
ISSN: 1530-6984
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Semiconductor Physics Section
Solid State Physics and Magnetism Section
× corresponding author
# (joint) last author

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