All-metallic nonlocal spin valves using polycrystalline Co₂(FeMn)Si Heusler alloy with large output

Abstract

A large output voltage of 0.7 mV at 1 mA charge current is demonstrated for all-metallic nonlocal spin valves using Co2(FeMn)Si Heusler alloy and Cu with a junction area of about 50 nm2. The output is attributed to the junction size reduction as well as to the high spin polarization in the Heusler alloy. An analysis using a one-dimensional model reveals that the spin diffusion length in the Cu layer shows no clear degradation even in the case of a 50 nm2 junction. When the junction is reduced further to 10 nm2, an output voltage of about 10 mV is expected.