Anisotropic magnetic susceptibility of multiwalled carbon nanotubes

Magnetic susceptibility of partially aligned multiwalled carbon nanotubes has been studied using superconducting quantum interference device magnetometry. Partial alignment of multiwalled nanotubes was produced by uniaxially straining composites of carbon nanotubes embedded in polymer matrices. The degree of alignment was determined by x-ray diffraction. The observed magnetic response is diamagnetic and anisotropic with the component along the nanotubes less diamagnetic than that of the perpendicular. The observed anisotropy is consistent with theoretical predictions, but it contradicts earlier experimental findings. (C) 2000 American Institute of Physics. [S0003- 6951(00)04011-0].