Temperature and bias voltage dependencies of spin injection signals for Co ₂FeAl _0.5Si _0.5/n-GaAs schottky tunnel junction

We investigated the temperature and bias voltage dependencies of spin injection signals for Co ₂FeAl _0.5Si _0.5 (CFAS)/n-GaAs schottky tunnel junction. Clear voltage change was observed at 10K for the junction by 3 Terminal Hanle measurements. The maximum voltage change, ΔV _MAX, was decreased with increasing temperature and observed up to 100 K. The estimated spin relaxation time, τ, was 290 ps at 10K and was also decreased with increasing temperature. In addition, temperature dependency of τ was lower than that of ΔV _MAX. The ΔV _MAX was increased with increasing bias voltage, and the sign of ΔV _MAX was reversed by opposite bias voltage direction. Moreover, bias dependency of ΔV _MAX became insensitive with increasing temperature.