Coherent Spin Polarization in an AC-Driven Mesoscopic Device

The spin transport characteristics through a mesoscopic device are investigated under the effect of an AC-field. This device consists of two-diluted magnetic semiconductor (DMS) leads and a nonmagnetic semiconducting quantum dot. The conductance for both spin parallel and antiparallel alignment in the two DMS leads is deduced. The corresponding equations for giant magnetoresistance (GMR) and spin polarization (SP) are also deduced. Calculations show an oscillatory behavior of the present studied parameters. These oscillations are due to the coupling of photon energy and spin-up & spin-down subbands and also due to Fano-resonance. This research work is very important for spintronic devices.