Rashba Spin Orbit Interaction On The Electronic Transport Properties Of Ferromagnetic / Ferromagnetic Semiconductor / Ferromagnetic Spin Valve Structure

Spintronics is one of the areas of current scientific interest in condensed matter physics and material sciences. The development of its theory, on the one hand, leads to the miniaturization, rapidity of the magnetic devices;on the other hand, it endows the magnetic devices with high sensitivity and saving density. Having abundant physical conceptions from the foundational research of spintronics, the study of application has definite applied target and broad market prospect as well.In recent years, spin-dependent transport in the ferromagnet/ semiconductor/ ferromagnet heterojunction has drawn attention and it has been widely investigated. Consequently, some theoretical results have been acquired. Based on the anterior research, we replace ferromagnetic semiconductor with semiconductor. In this paper we theoretically investigate the electronic transport phenomena in the ferromagnet(F)/ ferromagnetic semiconductor(FS)/ ferromagnetic(F) heterojunction. It can reveal the new effect within the quantum structure and the physics mechanisms thus. We also expect to provide theoretical foundation for the development of novel quantum devices through our work.The main results obtained in this paper are listed as follows:(1)Based on transfer matrix method, the quantum size and Rashbaspin-orbit coupling are considered simultaneously in this paper. Usingthe model of Rashba spin-orbit coupling, we investigate thetransmission coefficient against the length of the ferromagneticsemiconductor, transmission coefficient against the Rashba spin-orbit coupling parameters, spin-polarization as a function of Rashba spin-orbit coupling parameter and tunnelling magnetoresistance (TMR) as a function of Rashba parameter. Our calculated results demonstrate that with the effects of the Rashba spin-orbit interaction and those of the angle between the left and the middle magnetic moment, the transmission for spin-up and spin-down electrons shows angular-dependent periodic variation. The numerical results of the TMR indicate that quantum spin valve effect can be modified not only by the angle between the left and the middle magnetic moments but also by Rashba spin-orbit interaction.(2) Making use of the group velocity concept, we investigated the traversal time in the ferromagnet/ ferromagnetic semiconductor /ferromagnet heterojunction in the presence of Rashba spin-orbit coupling. The calculated numerical results show that whether the left and the middle magnetic moments become a parallel or an antiparallel configuration, in this structure as the length of the FS increases, the traversal time does not increase linearly but appears as step behavior. Meantime, compared with previous bibliographies, the traversal time in this structure becomes much shorter.