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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.

Based on a novel magnetic nanostructure with zero average magnetic field, a spin spatial splitter was recently proposed. This paper reports on how to effectively manipulate this device using a transverse electrical field with an applied bias. With the help of the stationary phase method, the lateral displacement and its spin polarization are calculated for the electron across this device. Both magnitude and sign of spin polarization are found to vary sensitively with this applied electric field. Thus, this device can be controlled conveniently by electric means, and can consequently serve as an electrically-tunable spin spatial splitter for spintronics applications.

We report a theoretical study of spin-dependent transport in a magnetic nanostructure, which can be experimentally realized by depositing a ferromagnetic metal (FM) stripe and a Schottky metal (SM) stripe on the top and at the bottom of the semiconductor heterostructure. Theoretical analysis reveals that the intrinsic symmetry in a single FM-stripe magnetic system can be broken by the SM stripe placed at the bottom of the heterostructure, and thus a sizeable spin polarization effect appears. Numerical calculation shows that not only amplitude of the spin polarization but also its sign varies with the width and/or the position of the SM stripe.

We theoretically investigate the lateral displacement of the spin electron across a hybrid magnetically modulated nanostructure. Experimentally, this nanostructure can be produced by depositing a ferromagnetic stripe with in-plane magnetization and a Schottky metal stripe on top and bottom of a semiconductor heterostructure, respectively. Theoretical analysis reveals that the inclusion of the Schottky metal stripe in single ferromagnetic-stripe nanostructure can break the intrinsic symmetry and a sizeable spin polarization in the lateral displacement will occur. Numerical calculations demonstrate that both magnitude and sign of the spin polarization can be controlled by adjusting the width and/or the position of the Schottky metal stripe in the device. Thus, based on such a hybrid magnetically modulated nanostructure, a spatial spin splitter can be proposed successfully.

We theoretically investigate spin transport in a novel magnetic nanostructure with zero average magnetic field, which can be experimentally realized by depositing three ferromagnetic stripes with a vertical magnetization on top and bottom of a semiconductor heterostructure. It is shown that, the electronic transmission is spin dependent, though the magnetic field is averagely vanishing, i.e., this device shows an obvious spin polarization effect. It is also shown that the degree of spin polarization depends on the incident energy and the incident direction of the electron. Therefore, such a magnetic nanostructure may be used as a spin filter for spintronics applications.

We theoretically explore the control of the wave-vector filtering (WVF) effect in a hybrid magnetic-electric-barrier nanostructure, which can be experimentally realized by depositing a ferromagnetic (FM) stripe and a Schottky-metal (SM) stripe on top and bottom of a GaAs/Al $$_{\text {x}}$$ Ga $$_{1-x}$$ As heterostructure, respectively. It is shown that an obvious WVF effect appears in such a device. It is also shown that the degree of the WVF effect is related to the width and position of the SM stripe. In particular, the WVF effect can be tuned by the applied voltage to the SM stripe, and thus a manipulable momentum filter can be obtained for nanoelectronics applications.