Anisotropic magnetic susceptibility of multiwalled carbon nanotubes

Magnetic susceptibility of partially aligned multiwalled carbon nanotubes h as been studied using superconducting quantum interference device magnetome try. 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 magne tic response is diamagnetic and anisotropic with the component along the na notubes less diamagnetic than that of the perpendicular. The observed aniso tropy is consistent with theoretical predictions, but it contradicts earlie r experimental findings. (C) 2000 American Institute of Physics. [S0003- 69 51(00)04011-0].