We report on a systematic temperature dependent X-band electron paramagnetic resonance (EPR) study of nano-sized graphite particles prepared by ball-milling. In as-prepared samples a very intense and sharp EPR resonance at g=2.0035 has been measured. The EPR linewidth shows a Korringa-like linear temperature dependence arising due to the coexistence and strong exchange coupling of itinerant and localized edge states. With a prolonged aging in inert atmosphere changes in the EPR signal suggest gradual structural reconstruction where the localized edge-states dominate the EPR signal. In this case the EPR spin susceptibility shows a maximum at ≈23K indicating the development of antiferromagnetic correlations as expected for the graphene lattice with a bipartite symmetry.
Cite
@article{arxiv.1108.4259,
title = {EPR study of nano-structured graphite},
author = {Jonas Kausteklis and Pavel Cevc and Denis Arcon and Lucia Nasi and Daniele Pontiroli and Marcello Mazzani and Mauro Ricco},
journal= {arXiv preprint arXiv:1108.4259},
year = {2011}
}
Comments
6 pages, 5 figures; accepted in Phys. Rev. B as regular article