Electrical Determination Of The Spin Relaxation Time Of Photoexcited Electrons In Gaas

Spin-dependent transport for photoexcited electrons in an epitaxial Fe/GaAs interface was characterized from 5 to 300 K. The presence of spin-dependent transport was confirmed at all the measured temperatures and the spin polarization across the interface is found to increase with decreasing temperature. A time-of-flight-type model based on the Dyakonov-Perel (DP) spin relaxation mechanism was employed to explain the temperature dependence, providing that the estimated spin relaxation time in GaAs is 62 ps at 5 K. This short spin relaxation time can be explained by the stronger efficiency of the DP mechanism for hot-electrons.