High spin injection polarization at an elevated dc bias in tunnel-junction-based lateral spin valves

Submicron metallic lateral spin valves are fabricated with AlOx tunnel junctions as spin injection and detection barriers. The spin polarization is estimated to be ∼20%, determined by both Hanle effect and variations of device dimensions. The polarization is maintained at a large dc injection current density >2×106 A/cm2. Both the spin polarization and spin diffusion length are weakly temperature dependent.