Magnetic zigzag edges of graphene are considered as a basis for novel spintronics devices despite the fact that no true long-range magnetic order is possible in one dimension. We study the transverse and longitudinal fluctuations of magnetic moments at zigzag edges of graphene from first principles. We find a high value for the spin wave stiffness D = 2100 meV \AA2 and a spin-collinear domain wall creation energy Edw = 114 meV accompanied by low magnetic anisotropy. Above the crossover temperature Tx≈10 K the spin correlation length ξ∝T−1 limits the long-range magnetic order to ~1 nm at 300 K while below Tx it grows exponentially with decreasing temperature. We discuss possible ways of increasing the range of magnetic order and effects of edge roughness on it.
@article{arxiv.0711.0207,
title = {Magnetic Correlations at Graphene Edges},
author = {Oleg V. Yazyev and M. I. Katsnelson},
journal= {arXiv preprint arXiv:0711.0207},
year = {2008}
}