Spin transport in an asymmetrical magnetic superlattice

The electron spin transport in an asymmetrical magnetic superlattice (MSL), which is due to the periodic barriers with abnormal one in height, has been theoretically studied. The effects of the abnormal barrier in the MSL have been introduced by a defined asymmetry factor, which corresponds to the changeable height of the abnormal barrier. The results show that in the ballistic transport region, the spin-up electron transmission and conductance can be dramatically depressed by the enhancement of the asymmetry factor. However, the spin-down transmission and conductance are only slightly affected. It means that the spin transport in the asymmetric MSL is obviously different from that in the symmetric MSL. In addition, the value of spin polarization of the conductance can be well controlled by the asymmetry factor in a wide range of energy, and highly polarized transport is possible. Furthermore, the number of the abnormal barriers can also strongly affect the oscillation of the spin polarization. (c) 2006 American Institute of Physics.