Non-local detection of spin-polarized electrons at room temperature in Co50Fe50/GaAs Schottky tunnel junctions

A clear spin-valve signal and a Hanle signal were observed in a Co50Fe50/n-GaAs Schottky tunnel junction through a four-terminal non-local geometry. The sign and magnitude of the spin-valve signal were strongly dependent on the bias current, suggesting that the spin polarization at the Co50Fe50/n-GaAs interface had strong energy dependence. A clear spin-valve signal was observed at temperatures up to 290 K. The magnitude of the spin-valve signal monotonically decreased by a factor of 7.9 as the temperature increased from 10 K to 290 K; this factor was significantly smaller than the factors reported for Fe/n-GaAs junctions which range from 35 to 80.