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We report on a theoretical study of giant magnetoresistance (GMR) effect in a δ -doped GaAs / Al x Ga 1 − x As heterostructure modulated by two stripes of ferromagnetic metal and a stripe of Schottky metal in parallel configuration. The δ -doping dependent transmission and conductance of the device are calculated. It is shown that a considerable giant magnetoresistance (GMR) effect exists in this structure. It is also shown that the magnetoresistance ratio ( MR ) can be switched by the δ -doping. The underlying physical mechanism of the results is analysed in light of δ -doping-dependent tunneling process in the device. [ABSTRACT FROM AUTHOR]

We report a theoretical study on spin-polarized lateral displacement for the electron across a magnetic nanostructure with a zero average magnetic field, which can be experimentally realized by depositing a ferromagnetic stripe with a plumb magnetization on the top of a semiconductor heterostructure. It is shown that, the lateral displacement depends strongly on the electron spins due to the Zeeman coupling and the intrinsic symmetry, though the average magnetic field is vanishing in the nanostructure. It is also shown that the spin-polarized lateral displacement is related closely to the structural parameters. Therefore, such a novel magnetic nanostructure may be used as a spin spatial splitter for spintronics applications. [ABSTRACT FROM AUTHOR]

A Magnetoresistance device is proposed in a both magnetically and electrically modulated two-dimensional electron gas, which can be realized experimentally by the deposition, on the top and bottom of a semiconductor heterostructure, of two parallel metallic ferromagnetic strips under an applied voltage. It is shown that a considerable magnetoresistance effect can be achieved in such a device due to the significant transmission difference for electrons through parallel and antiparallel magnetization configurations. It is also shown that the magnetoresistance ratio depends strongly on the applied voltage to the stripe in the device. These interesting properties may provide an alternative scheme to realize magnetoresistance effect in hybrid ferromagnetic and semiconductor systems, and this system may be used as a voltage-tunable magnetoresistance device. [ABSTRACT FROM AUTHOR]