Room-temperature local magnetoresistance effect in n-Ge devices with low-resistive Schottky-tunnel contacts

Two-terminal local magnetoresistance (MR) effect in n-type germanium (Ge) based lateral spin-valve (LSV) devices can be observed at room temperature. By using phosphorus delta-doped Heusler-alloy/Ge Schottky-tunnel contacts, the resistance-area product of the contacts is able to be less than 0.20 k Omega mu m(2), which is the lowest value in semiconductor based LSV devices. From the one-dimensional spin drift-diffusion model, the interface spin polarization of the Heusler-alloy/Ge contacts in the present LSV devices can be estimated to be similar to 0.018 at room temperature. We experimentally propose that it is important for enhancing the local MR ratio in n-Ge based LSV devices to improve the interface spin polarization of the Heusler-alloy/Ge contacts. (C) 2019 The Japan Society of Applied Physics