Electrical spin injection in multiwall carbon nanotubes with transparent ferromagnetic contacts

We report on electrical spin injection measurements on multiwall carbon nanotubes (MWNTs). We use a ferromagnetic alloy Pd1-xNix with x approximate to 0.7 which allows us to obtain devices with resistances as low as 5.6 k Omega at 300 K. The yield of device resistances below 100 k Omega, at 300 K, is around 50%. We measure at 2 K a hysteretic magneto-resistance due to the magnetization reversal of the ferromagnetic leads. The relative difference between the resistance in the antiparallel (AP) orientation and the parallel (P) orientation is about 2%. (C) 2005 American Institute of Physics.