Diamagnetism of some quasi-two-dimensional graphites and multiwall carbon nanotubes

The diamagnetic susceptibility (DMS) of quasi-two-dimensional graphites (QTDGs) and multiwall carbon nanotubes (MWCNs) was measured at 4-950 K. The DMS of these carbons was explained by means of the band model of QTDG. The high average DMS value of QTDGs and MWCNs is associated with DMS normal to graphene sheets: the orbital diamagnetism of 2D conduction carriers. The DMS values along the sheets and nanotubes axes are close to the atomic one, i.e. they are 2 orders of magnitude less than those normal to the sheets and to MWCNs axes. (C) 1997 Elsevier Science B.V.