Dilute magnetic semiconductors in spin-polarized electronics (invited)

Dilute magnetic semiconductors have proven to be very useful in building an all-semiconductor platform for spintronics—so far they provide the only viable route to establish spin-polarized current injection into a nonmagnetic semiconductor. The reasons for this become apparent from a simple spin-channel model, which predicts that spin injection into a semiconductor can, within linear response, only readily be achieved from a ferromagnetic injector that has: (i) a resistivity that is comparable to the semiconductor and (ii) preferably is 100% spin polarized. Both of these criteria can be met in magnetic semiconductors, but (so far) are hard to achieve using other materials. Experimentally, we demonstrate how dilute magnetic II–VI semiconductors can be used to inject a strongly (up to 90%) spin-polarized current into a light emitting diode. In addition, we discuss the implications of the spin-channel model for the observation of giant magnetoresistance-like effects in the magnetoresistance of an all-semiconductor device. © 2001 American Institute of Physics.