A study was made of the changes in the electronic structure caused by lattice defects in graphene planes. In many cases, lattice distortions gave rise to localized states at the Fermi level. Electron-electron interactions led to the existence of local moments. The RKKY interaction between these moments was always ferromagnetic, due to the semi-metallic properties of graphene.

Local Defects and Ferromagnetism in Graphene Layers. M.A.H.Vozmediano, M.P.López-Sancho, T.Stauber, F.Guinea: Physical Review B, 2005, 72[15], 155121 (5pp)