Antiferro-ferromagnetic transition in ultrathin Ni(OH)2 layer grown on graphene surface and observation of interlayer exchange coupling in Ni(OH)2/graphene/Ni(OH)2 nanostructures

The major limitation of using graphene as a potential spacer element in interlayer exchange coupling (IEC) might be due to destruction of ferromagnetism as a result of the charge transfer effect at the interface if a transition metal based ferromagnetic layer is grown on the graphene surface. To overcome this problem, we have used the antiferromagnetic Ni(OH)(2) layer grown on the graphene surface to convert it ferromagnetic due to the charge transfer effect. By growing thin layers of Ni(OH)(2) on both sides of the graphene surface, strong antiferromagnetic IEC with ultralow coercivity (7 Oe) is observed. By lowering the nickel content, an ultrathin layer of Ni(OH)(2) is grown on either side of graphene and shows complete ferromagnetism with a giant coercivity of 4154 Oe. Ab initio calculations have been done to substantiate this kind of charge transfer effect at the interface of Ni(OH)(2) and graphene. Magnetotransport of the composite material is also investigated to understand the role of IEC in transport properties. Published by AIP Publishing.