通过关键词查论文: Spin Polarization

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作者: Sergey Dunaevsky, Evgeny Mikhailenko
摘要: The results of "ab-initio" calculations of spin - polarized electronic structure, total energy and the local atomic magnetic moments of some manganite surfaces are presented. A slab consisting of one, three, five or, in some cases, seven layers of Mn-O atoms. is used to model the CaMnO3 (CMO), LaMnO3 (LMO) (001) surface. Total energies calculations of magnetic properties of manganites surfaces were performed using density-functional theory (DFT) and the pseudopotential method. We have found that on the surface layers without structural optimization manganese atomic magnetic moment is higher than in the bulk and “dead layers”, where all the local moments are zero, have not been found. All the above ultrathin films appeared ferromagnetic semimetals with almost complete polarization of DOS near the Fermi level.
105
作者: Lei Feng, Fei Wang, Jia Li, Shuang Jin Wang
摘要: Ti-based Heusler compounds are rare reported widely up to now. In this paper, ternary full-Heusler compound Ti2NiIn is systematically studied by first-principles calculations. The calculations show the compound has a complete spin polarization around the Fermi level in the total density of state. The majority spin shows strongly metallic character, while the minority spin has an insulating behavior in its band structure. The compound has a precisely total magnetic moment of-3.0μB per formula by first-principles calculations. This result complies well with the SlaterPauling (SP) rule. All the results show that Ti2NiIn with Hg2CuTi-type structure is a new half-meltal ferromagnet by first-principles calculations.
399
作者: Yi Lin Mi, Jiang Nan Gao
摘要: The spin injection efficiency in the ferromagnet/ organic semiconductors system (FM/OSE) was studied under an external electric-field. It is found that the spin injection efficiency can be strongly influenced by the spin-dependent electrical conductivity and the downstream spin diffusion length of polarons. With the increase of external electric-field, the downstream spin diffusion length increases and makes the spin-dependent electrical conductivity increase, too. So the spin injection efficiency is enhanced. When the external electric-field increases from 1 to 10 mV/μm at T=80K, the spin injection efficiency increases about 20%. It seems that the downstream spin diffusion length is an significant factor to affect the spin injection efficiency in the FM/ OSE under an external electric-field.
704
作者: Wei Lu, San Huang Ke
摘要: A novel doping scheme for graphene was recently realized experimentally by creating different vacancy complexes doped with a transition metal (TM) atom [nanoLett. 12, 141 (2012)]. This provides a new reliable way to modifying the electronic structure and transport property of graphene. Here, we show, by performing first-principles calculations, that the defect complex of TM@V4 (a TM atom doped tetra-vacancy) in zigzag graphene nanoribbons (ZGNRs) can lead to a 100% spin-polarized electron transport in a wide energy range around the Fermi energy. Analyses show that this is due to the particular atomic structure of the TM@V4 complex regardless of the species of the TM atom.
207
作者: A. Zywietz, J. Furthmüller, Friedhelm Bechstedt
643
作者: Jia Xiang Shang, Meng Qiu Guo
摘要: The electronic structure and magnetic properties of Ni/Al2O3/Ni tunnel junctions with O-terminated and Al-terminated interface models are investigated by first-principles discrete variational method with the local-spin-density approximation. The results show that the interface atomic has an important effect on interface electronic state and spin polarization as well as TMR ratio. For the O-terminated and Al-terminated interface models, spin polarization at Fermi level of Ni layers exhibit negative. It is found that absolute value of spin polarization as well as TMR ratio of Al-terminated interface models is much larger than that of O-terminated interface, which shows over-oxidization of Al layer could deteriorate magnetoresistance properties.
2540
作者: E.E. Shalyguina, Kyung Ho Shin, M.A. Karsanova, O.A. Shalyguina, I.A. Pogrebnaya
473
作者: Zahra Bamshad
摘要: I theoretically investigate the spin Polarization and transmission of the electrons in a nanostructure consisting barriers with periodic, parallel and also anti parallel magnetization .also I investigate polarization when distance between barriers is constant, or is increased, or is decreased periodically. These observable quantities are found to be strongly affected by both the magnetic configuration and the number of the periodic magnetic barriers. When the number of periods increases, in parallel magnetization for periodic increasing distance the polarization is enhanced so in parallel configuration it is better that distance between barriers to be increasing periodically. I investigate Polarization in these configuration in both delta function approximation and modulated magnetic barriers in x direction. This Polarization can be used in spintronics device.
833
作者: Yi Lin Mi, Feng Yan Liu, Jiang Nan Gao
摘要: Spin injection efficiency in the ferromagnet/ organic semiconductors system (FM/OSEs) was explored considering the spin dependence of the electric-conductivity induced by spin injection in the OSEs. It is known that the OSEs is spin polarized, once spin was injected from FM layer to OSEs layer. The up-spin polarons and the down-spin polarons have different density. The spin dependence of the electric-conductivity is so induced. In the literature, it was usually supposed that the electric-conductivity in the spin polarized OSEs is spin independent. So, it is crucial to reflect the physics in the spin injection. Our work shows that the spin-dependent electrical-conductivity is one of the significant factors which affect the spin injection efficiency. The spin injection efficiency increases obviously with the rising of the spin-dependent electrical-conductivity in the same spin injection system. And the effect becomes larger, when the polaron proportion increases. Furthermore, the effects of interfacial electrochemical-potential proportion on the spin injection efficiency in the heterojunction are also included.
416
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