Recent fabrication of atomic precision nanodevices for spintronics greatly boosted their performance and also revealed interesting features as oscillating magnetoresistance with a number of atomic layers in a multilayered structure. This motivates the need to go beyond the usual theoretical approach of semiclassical continuous layers. Here the simple tight-binding dynamics is used to describe quantum conduction in a multicomponent system with spin-polarized electrodes separated by an ultrathin and atomically coherent nonmagnetic spacer (either metallic or insulating). A possibility is indicated for obtaining a huge resonant enhancement of magnetoresistance in such device by a special choice of gate voltage on the spacer element.

• Received 20 February 2008

DOI:https://doi.org/10.1103/PhysRevB.78.094428