The Influence Of Spin-orbite Coupling Effects On Electronic Transportation At Spin-filter Magnetic Junction

The traditional electronics is mainly based on the charge properties of electrons. However, in mesecopic scale range, only considering the charge properties is not enough, the spin effect is needed to be considered also. Along with the discovering of the giant magneto resistance (GMR) and its great success in the practical applications, the Spintronics is gradually forming and drawing more and more people pay attention to. This paper mainly investigates the spin-dependent tunneling in double-spin filter junction with two semiconductor ferromagnetic layers. The spin-dependent transport relations with the molecular field, the rashba spin-orbit coupling, and their influences on the tunneling magnetoresistance are discussed. The structure and research contents in this paper are presented as follows.In the first chapter, the background and the development of spin electronics are briefly reviewed first. Then, the rashba spin-orbit coupling, the spin-filter effect and the tunneling magnetoresistance are discussed. In succession, the two important theoritical models in the magnetic tunneling junction study, i.e., Julliere model and Slonczewski free electron model are introduced.In the second chapter, based on the quantum coherent transport and the transfer method, the spin-dependent transportations in NM/FS/I/FS/NM (NM represents nonmagnetic mental layer, FS represents the ferromagnetic semiconductor layer, and I represents the nonmagnetic insulator layer) double spin-filter junction are discussed. The results show that the largest positive (negative) TMR values can be obtained when the Rashba spin-orbit coupling strength on both the right and left FS layers is equal (not equal); The stability TMR values can be obtained when the thickness of the insulating layer reaches to a certain value. The asymmetric influence of the molecule field on the up spin electrona is larger than that on the down spin electrons, so the large TMR values can be obtained by adjusting the size of the molecular field and the corresponding Rashba spin-orbit coupling strength.