▎ 摘　　要

A chemically synthesized graphitic material where the structural coherence between the layers is missing approximates very well the assembly of graphene sheets. Our multi-frequency (9.4-420 GHz) electron spin resonance (ESR) study clearly identifies itinerant and localized electrons below 50 K. The metallic signal ascribed to the conduction electrons in graphene is characterized by a remarkably long spin lifetime of 65 ns. Above this temperature incoherent in-plane and inter-plane scattering give a motionally narrowed single line at g = 2.0044. (C) 2014 Elsevier Ltd. All rights reserved.