Properties of K,Rb-intercalated C60 encapsulated inside carbon nanotubes called peapods derived from nuclear magnetic resonance
2015 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 118, no 11, 114305Article in journal (Refereed) Published
We present a detailed experimental study on how magnetic and electronic properties of Rb, K-intercalated C-60 encapsulated inside carbon nanotubes called peapods can be derived from C-13 nuclear magnetic resonance investigations. Ring currents do play a basic role in those systems; in particular, the inner cavities of nanotubes offer an ideal environment to investigate the magnetism at the nanoscale. We report the largest diamagnetic shifts down to -68.3 ppm ever observed in carbon allotropes, which is connected to the enhancement of the aromaticity of the nanotube envelope upon intercalation. The metallization of intercalated peapods is evidenced from the chemical shift anisotropy and spin-lattice relaxation (T-1) measurements. The observed relaxation curves signal a three-component model with two slow and one fast relaxing components. We assigned the fast component to the unpaired electrons charged C-60 that show a phase transition near 100 K. The two slow components can be rationalized by the two types of charged C-60 at two different positions with a linear regime following Korringa behavior, which is typical for metallic system and allow us to estimate the density of sate at Fermi level n(E-F).
Place, publisher, year, edition, pages
2015. Vol. 118, no 11, 114305
IdentifiersURN: urn:nbn:se:umu:diva-110518DOI: 10.1063/1.4931146ISI: 000361843300020OAI: oai:DiVA.org:umu-110518DiVA: diva2:866329