▎ 摘　　要

The recent prediction of the edge modification by a magnetic impurity spin to create half-metallicity in a graphene sheet is demonstrated. Ultrafine Mn3O4 sheets of size 10 nm are grown on graphene to observe the remarkable effect of half-metallicity with a 90% change in magnetoresistance at room temperature. The demonstration of a huge negative magnetoresistance using a magnetic impurity spin will make graphene a potential candidate for spintronic devices. (C) 2013 Elsevier Ltd. All rights reserved.