Electrical properties in magnetic field of macroscopic carbon nanotube objects

The electrical properties including zero-field resistivity, magnetoresistance and current-voltage (I-V) curves of macroscopic carbon nanotube (CNT) objects (yarns, bundles, films, and networks) have been measured. The macroscopic CNT objects exhibit semiconductor-like behaviors. Under the magnetic field applied perpendicular to the plane or axis of the Macroscopic CNT objects, a pronounced negative magnetoresistance have been observed. Due to the aligned, close-packed structure of MWNT yarn, its MR reach as high as -17% at 9 T. The I-V curves of the MWNT network exhibit a linear relationship even at low temperature, but the other samples exhibit a nonlinear relationship, indicating the effect of morphology and defects of CNTs in macroscopic CNT objects.