Magnetoresistance and spin diffusion in multi-wall carbon nanotubes

Studies of the spin diffusion and magnetoresistance of multiwall carbon nanotubes contacted to by both cobalt and gold electrodes in magnetic fields of up to 4T are reported. The measured room temperature contact resistance of the Au and Co electrodes ranged from 10^3 to 10^[email protected] The magnetoresistance of tubes contacted to by Au electrodes and measured up to 4T at 4.2 and 2.2K was observed to be negative. The maximum negative magnetoresistance for the nanotubes contacted to by Co electrodes was 25%. As the temperature was increased the magnetoresistance decreased and disappeared above 25K. The spin diffusion length was calculated to be 650nm.