Controllable electromagnetic response of onion-like carbon based materials

Here discussed electromagnetic response of onion-like carbon (OLC) powders with variable ratio of decreasing in size diamond core and defective curved graphitic shells (sp(2)/sp(3) nanocomposites) in Ka-band (26-37 GHz) band. sp(2)/sp(3) ratio in OLC was regulated by increasing of annealing temperature of explosive nanodiamond (ND) using as initial product. The observed one dimensional variable range hopping conductivity (4-300 K) combined with HR TEM data was attributed to the formation of variable length ribbon-like defective graphene scales. The increase of ND annealing temperature results in the increase of density states of conductive electrons and corresponding increase of conductivity of OLC produced. The increase of conductivity of OLC provides the increase of EM wave attenuation ability along with light increase of reflecting ability. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim