Spin-polarized transport in magnetically assembled carbon nanotube spin valves

Spin polarized transport over 5 mu m long carbon nanotubes (CNTs) is observed in magnetically assembled spin valves with electrochemically deposited ferromagnetic (FM) electrodes. An annealing procedure is developed to produce stable devices with highly transmissive FM/CNT contacts. The devices exhibit magnetoresistance (MR) with magnitudes up to 4%, and the sign of MR is consistently negative. The temperature dependence is investigated and MR is observed up to 14 K. Bias dependence is also investigated, with MR persisting up to similar to 300 mV. (c) 2006 American Institute of Physics.