In-plane anisotropy of tunneling magnetoresistance and spin polarization in lateral spin injection devices with (Ga,Mn)As/GaAs spin-Esaki diode contacts

We report here on in-plane anisotropy observed in the tunneling magnetoresistance of (Ga,Mn)As/n+-GaAs Esaki diode contacts and in the spin polarization generated in lateral all-semiconductor, all-electrical spin injection devices, employing such Esaki-diode structures as spin aligning contacts. The uniaxial component of the registered anisotropies, observed along [1 1 0] directions, does switch its sign as an effect of the applied bias, however the switching occurs at different bias values for magnetoresistance and for spin polarization cases.