Ferromagnetism in Graphene Nanoribbons: Split versus Oxidative Unzipped Ribbons

• DOI: 10.1021/nl203512c
• Publication Date: 2012-02-09T19:24:12Z
• Authors: S. S. Rao; S. Narayana Jamma...; A. Stesmans; V. V. Moshchalkov; J. van Tol; D. V. Kosynkin; A. Higginbotham-D...; J. M. Tour
• Keywords: Exchange bias

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