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 Pd 1 − x Ni x with x ≈ 0.7 which allows us to obtain devices with resistances as low as 5.6 k Ω at 300 K. The yield of device resistances below 100 k Ω , 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 ( A P ) orientation and the parallel ( P ) orientation is about 2%.