Electrical spin injection and accumulation in CoFe/MgO/Ge contacts at room temperature

Abstract

We report the all-electrical spin injection and detection in CoFe/MgO/moderately doped n-Gecontact at room temperature (RT), employing three-terminal Hanle measurements. A sizable spin signal of similar to 170 k Omega mu m(2) has been observed at RT, and the analysis using a single-step tunneling model gives a spin lifetime of similar to 120 ps and a spin diffusion length of similar to 683 nm in Ge. The observed spin signal shows asymmetric bias and temperature dependences which are strongly related to the asymmetry of the tunneling process.