Lateral silicon spin-valve devices with large spin-dependent magnetoresistance and output voltage

Abstract

We investigated the spin transport in nanoscale silicon (Si)-based spin-valve devices with a 20 nm Si channel and a Fe/(Mg)/MgO/Ge stack as the spin injector/detector. By optimizing the MgO barrier thickness, we achieved a large spin-dependent output voltage of 25 mV at 15 K. Furthermore, by inserting an ultrathin (1 nm) Mg layer between the the Fe layer and the tunnel barrier MgO layer to prevent the formation of a magnetically-dead layer, we have increased the spin-valve ratio up to –3.6% at 15 K. These are the highest values reported in lateral Si-based spin-valve devices.