Research About Tunneling Time In The Ferromagnet/insulator/ferromagnet Magnetic Junction

Recently because its higher Tunneling Magnetoresistance (TMR) and lower power dissipation play an important role in field sensor and magnetic record, the study on a tunnel magnetic junction consisting of two ferromagnetic layers separated by a thin insulator(I) layer, that is FM/I/FM tunnel magnetic tunneling junction, has attracted considerable attention. With the advance on miniaturizing tunneling devices, the time aspect of the tunneling process has been the focus of much research in the last decade. Beyond its intrinsic quantum mechanics interest, the significance of tunneling time comes from the requirement of understanding the tunneling dynamics in high-speed devices due to the fact that the time is one of key parameters for ultimate performance evaluation of different kinds of electronic devices.In the first chapter, we introduce the development of spintronics and spin-polarization, and also simply introduce significance and survey of the magnetic tunnel junctions system. Then the correlative mechanism of the TMR effect is briefly generalized. Following, we analyzed the two familiar theoretical explanations of Julliere model and Slonczewski model. Finally, we introduce the development and several description of tunneling time.In the second chapter, based on the phase time definition, we investigate the spin-dependent electron tunneling time of FM/I(S)/FM magnetic junction with the variation of the angle between the two magnetic moments of the two ferromagnet layers, the width of the barrier and the incident energy. In addition, we indicate the new effect and physical mechanics of this quantum structure. We expect to provide some useful information for the development of novel quantum devices with our work.