Spin relaxation in a germanium nanowire

We report experimental study of spin transport in nanowire spin valve structures consisting of three layers-cobalt, germanium, and nickel. The spin diffusion length in the Ge is estimated to be about 400 nm at 1.9 K and the corresponding spin relaxation time is about 4 ns. At 100 K, the spin diffusion length drops to 180 nm and the relaxation time is about 0.81 ns. These short relaxation times, which depend weakly on temperature, are caused by strong surface roughness scattering that causes rapid spin relaxation via the Elliott-Yafet mode [Elliott, Phys. Rev. 96, 266 (1954)]. (c) 2006 American Institute of Physics.