Observation of strongly enhanced inverse spin Hall voltage in Fe3Si/GaAs structures

We performed spin pumping experiment on high quality, epitaxial Fe3Si/GaAs structures grown by molecular beam epitaxy. By tailoring the thickness and doping (n, p) level of the conducting GaAs epi-layer, thermal heating common of ferromagnetic metal/semiconductor heterostructure was removed effectively. A large inverse spin Hall Effect (ISHE) voltage up to 49.2 mu V was observed for Fe3Si/p-GaAs. Smaller ISHE voltage (V-ISHE) by a factor of similar to 0.4 was obtained for Fe3Si/n-GaAs, as scaled with its resistivity. By taking into account of the self-induced ISHE apparently observed in our samples, the minimum value of spin Hall angle theta(ISHE) for n-GaAs and p-GaAs was estimated to be 1.9 x 10(-4) and 2.8 x 10(-5), respectively. (C) 2014 AIP Publishing LLC.