Verification of electrical spin injection into InGaAs two-dimensional electron gas from CoFe electrode by four-terminal non-local geometry

We performed electrical spin injection into In0.75Ga0.25As two-dimensional electron gases from Co0.8Fe0.2 electrodes by four-terminal non-local spin-valve (NLSV) measurement. We observed clear SV signals in NL resistance at 1.5 K. From the electrode spacing dependence of the signals, we estimated spin diffusion length and spin polarization to be similar to 5.1 mu m and similar to 5.7 %, respectively. These are larger than those reported in similar systems.