  We observed spin injection into silicon through Fe/MgO tunnel barrier by
using non-local magnetoresistance measurement technique. Fe/MgO tunnel barrier
contacts with a lateral spin valve structure were fabricated on phosphorous
doped silicon-on-insulator substrate. Spin injection signals in the non-local
scheme were observed up to 120K, which is the highest value where band
transferred spins in Si have ever been reported, and spin diffusion length was
estimated to be about 2.25um at 8K. Temperature dependence and injection
current dependence of the non-local voltage were also investigated. It is
clarified that MgO tunnel barrier is effective for the spin injection into
silicon.
