Spin Injection, Transport, and Detection in a Lateral Spin Transport Devices with Co₂FeAl_0.5Si_0.5/n-GaAs, Co₂FeSi/MgO/n-Si, and CoFe/MgO/n-Si Junctions

Abstract

We demonstrate spin injection, transport, and detection in a lateral spin transport devices with Co₂FeAl_0.5Si_0.5/n-GaAs, Co₂FeSi/MgO/n-Si, and CoFe/MgO/n-Si junctions. Non-local four- and three-terminal Hanle-effect signals indicate large spin injection/detection efficiency in Si for Co₂FeSi/MgO/Si on insulator (SOI) devices compared with CoFe/MgO/SOI devices, whereas the preparation methods of MgO layers on SOI are exactly same in both devices. The estimated spin injection/detection efficiency in GaAs is 0.06 at 4.2 K, which is also larger than those of the devices with Fe and CoFe electrodes. Different properties in the bias voltage dependences on the amplitude of spin accumulation signals are also observed between Co₂FeSi/MgO/SOI and CoFe/MgO/SOI devices. These results indicate that the species of ferromagnetic material definitely influences the amplitude and the behavior of the spin signals.