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

Abstract

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 δ-doped Heusler-alloy/Ge Schottky-tunnel contacts, the resistance-area product of the contacts is able to be less than 0.20 kΩ μm2, 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 ∼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.