Room-temperature spin transport in n-Ge probed by four-terminal nonlocal measurements

Abstract

We demonstrate electrical spin injection and detection in n-type Ge (n-Ge) at room temperature using four-terminal nonlocal spin-valve and Hanle-effect measurements in lateral spin-valve (LSV) devices with Heusler-alloy Schottky tunnel contacts. The spin diffusion length (λGe) of the Ge layer used (n ∼ 1 × 1019 cm−3) at 296 K is estimated to be ∼0.44 ± 0.02 µm. Room-temperature spin signals can be observed reproducibly in the low bias voltage range (≤0.7 V) for LSVs with relatively low resistance–area product (RA) values (≤1 kΩ µm2). This means that the Schottky tunnel contacts used here are more suitable than ferromagnet/MgO tunnel contacts (RA ≥ 100 kΩ µm2) for developing Ge spintronic applications.