Observation of local magnetoresistance signals in a SiGe-based lateral spin-valve device

Abstract Utilizing a Si 0.1 Ge 0.9 layer grown on Ge/Si(111) as a spin-transport channel and a Co 2 FeAl 0.5 Si 0.5 ferromagnetic epilayer as a spin injector and detector, we demonstrate two-terminal local magnetoresistance signals at low temperatures in SiGe based lateral spin-valve devices. The magnitude of the local magnetoresistance signals is twice as large as that of nonlocal signals below 50 K. The local magnetoresistance signal can be observed up to 225 K, at which the nonlocal magnetoresistance signals already disappear. To observe the local magnetoresistance signal at higher temperatures, we should consider the spin detection sensitivity of the spin detector contact in the used lateral spin-valve devices.