Pure spin current transport in a SiGe alloy

TL;DR

This paper demonstrates pure spin current transport in a SiGe alloy using nonlocal magnetoresistance measurements, revealing key spin transport parameters and opening pathways for spintronic applications with SiGe materials.

Contribution

First experimental observation of pure spin current transport in a SiGe alloy, with detailed measurements of spin diffusion length and lifetime.

Findings

Spin diffusion length ~0.5 μm at low temperatures

Spin lifetime ~0.2 ns at low temperatures

Successful detection of nonlocal spin signals and Hanle effect

Abstract

Using four-terminal nonlocal magnetoresistance measurements in lateral spin-valve devices with Si$_{\rm 0.1}$Ge$_{\rm 0.9}$, we study pure spin current transport in a degenerate SiGe alloy ($n \sim$ 5.0 $\times$ 10$^{18}$ cm$^{-3}$). Clear nonlocal spin-valve signals and Hanle-effect curves, indicating generation, manipulation, and detection of pure spin currents, are observed. The spin diffusion length and spin lifetime of the Si$_{\rm 0.1}$Ge$_{\rm 0.9}$ layer at low temperatures are reliably estimated to be $\sim$ 0.5 $\mu$m and $\sim$ 0.2 ns, respectively. This study demonstrates the possibility of exploring physics and developing spintronic applications using SiGe alloys.