Pure spin current transport in a SiGe alloy

Using four-terminal nonlocal magnetoresistance measurements in lateral spin-valve (LSV) 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 of the Si$_{\rm 0.1}$Ge$_{\rm 0.9}$ layer at low temperatures is estimated to be $\sim$ 0.5 $\mu$m. Because of the similar conduction band structure to pure Ge, the spin-transport properties are nearly consistent with the recent results of degenerate Ge [Phys. Rev. B {\bf 94}, 245302 (2016); Phys. Rev. B {\bf 95}, 161304(R) (2017).]. This study shows a possibility to explore physics and to develop spintronic applications in the field of SiGe alloys.