Appearance of Anisotropic Magnetoresistance and Electric Potential Distribution in Si-Based Multiterminal Devices With Fe Electrodes

We have investigated the influence of anisotropic magnetoresistance (AMR) on nonlocal signals in Si-based multiterminal devices with ferromagnetic Fe electrodes. The AMR of the Fe electrodes has a significant influence on nonlocal signals when the in-plane device structure is not optimized. Our conformal mapping calculations show that it is virtually impossible to realize a pure spin current by spin diffusion because of the electric potential distribution in the depth direction in the Si channel when the ferromagnetic electrodes are directly fabricated on the Si channel. We discuss the influence of structure on the electric potential distribution, which is indispensable for an analysis of spin-dependent transport.