An All Electrical Spin Detector

In this paper we propose a spin detector based on the exchange interaction between the conduction electrons and a nearby spin array. The device structure is very close to a spin-valve device in an anti-parallel (AP) configuration. We show that in such a structure, the spin information can be obtained from the second derivative of the current. Our calculations based on realistic device parameters show that as small as a single spin should be detectable with a very high spatial resolution. Ideal half-metallic contacts would give the optimum performance for the proposed detector. However, when spin-injection efficiency is limited, we show that using an appropriate de-embedding scheme, the spin information can still be retained.