Enhanced spin signals due to native oxide formation in Ni80Fe20/Ag lateral spin valves

Large nonlocal spin valve signals are reported in mesoscopic Ni80Fe20/Ag lateral spin valves upon exposing them to air. Magnetotransport measurements combined with transmission electron microscopy show that the formation of a native oxide layer at the Ni80Fe20/Ag interface is responsible for the large signals. The results indicate that lateral spin valves with superior performance to those based on high-resistance tunnel barriers can be achieved via controllable growth of native permalloy oxides.