Room temperature electrical injection and detection of spin polarized carriers in silicon using MgO tunnel barrier

We are reporting room-temperature, all electrical injection and detection of spin polarized carriers in silicon using NiFe/ MgO tunnel-barrier-contacts. From the magnetic field dependence of the spin accumulation voltage, spin-lifetime, and diffusion-length of the carriers were determined to be 276 ps and 328 nm, respectively. For comparison, similar experiments were also performed using NiFe/Al2O3 tunnel-barrier-contacts. However, in the latter case spin-lifetime and diffusion-length were found to be lower (similar to 107 ps, 204 nm) demonstrating the superiority of MgO barrier for spin-injection application. Attaining spin diffusion lengths of >320 nm in Si channels is a ground breaking step and opens tremendous opportunities for integrating spin functionality into post-Moore-era electronic devices. (C) 2011 American Institute of Physics. [doi:10.1063/1.3564889]