Low-field magnetocurrent above 200% in a spin-valve transistor at room temperature

A spin-valve transistor (SVT) that employs hot electrons is shown to exhibit a huge magnetotransport effect at room temperature in small magnetic fields. The SVT is a ferromagnet-semiconductor hybrid structure in which hot electrons are injected into a NiFe/Au/Co spin valve, and collected on the other side with energy and momentum selection. This makes the collector current extremely sensitive to spin-dependent scattering. The hot-electron current output of the device changes by more than a factor of three in magnetic fields of only a few Oe, corresponding to a magnetocurrent above 200% at room temperature.