Spin injection, transport, and detection at room temperature in a lateral spin transport device with Co₂FeAl_0.5Si _0.5/n-GaAs schottky tunnel junctions

We observed spin-valve signals and Hanle signals in four-terminal nonlocal measurements on a lateral spin transport device with Co₂FeAl _0.5Si_0.5(CFAS)/n-GaAs Schottky tunnel junctions. The estimated spin injection/detection efficiency was 0.06 at 4.2 K, which is larger than those of the devices with Fe and CoFe electrodes [Nature Physics 3 (2007) 197 and Appl. Phys. Lett. 99 (2011) 082108]. The spin diffusion length estimated from Hanle signals was consistent with the gap length dependency of the spin-valve signals. Furthermore, the spin-valve signals were observed at up to 290 K. This is the first demonstration of detecting spin accumulation in semiconductor with full-Heusler alloys electrodes at room temperature.