共查询到18条相似文献,搜索用时 78 毫秒
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利用磁控溅射方法沉积双势垒磁性隧道结多层膜, 其中Al-O势垒层由等离子体氧化1 nm厚的 金属铝膜方式制备,然后采用深紫外光曝光和Ar离子刻蚀技术、微加工制备出长短轴分别为 6和3 μm大小的椭圆形双势垒磁性隧道结(DBMTJ),并在室温和低温下对其自旋电子输运 特性进行了研究. DBMTJ的隧穿磁电阻(TMR)比值在室温和42 K分别达到27%和423%, 结电阻分别为136 kΩ·μm2和175 kΩ·μm2,并在实验中观 察到平行状 态下存在低电阻态及共振隧穿效应,反平行态下呈现高电阻态以及TMR随外加偏压或直流电 流的增加而发生振荡现象. 由此,设计了一种基于这种双势垒磁性隧道结隧穿特性的自旋晶 体管.
关键词:
双势垒磁性隧道结
隧穿磁电阻
共振隧穿效应
自旋晶体管 相似文献
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文章介绍了一个基于弱Hund耦合规则以及载流子漂移扩散机制所提出的关于钙钛矿氧化物p-n异质结构的自旋极化输运机制的物理模型.该理论不仅可以很好地解释由具有负磁阻效应的La0.9Sr0.1MnO3(LSMO)与非磁性的SrNb0.01Ti0.99O3(SNTO)所组成的异质结中所存在的正磁电阻效应,同时揭示了该体系中LSMO在界面区域的载流子与远离界面区域的载流子具有不同的自旋极化方向.这一结果将为理解钙钛矿氧化物异质结及多层膜的自旋极化输运机制开辟了一条新的途径. 相似文献
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文章介绍了一个基于弱Hund耦合规则以及载流子漂移扩散机制所提出的关于钙钛矿氧化物p-n异质结构的自旋极化输运机制的物理模型.该理论不仅可以很好地解释由具有负磁阻效应的La0.9Sr0.1MnO3(LSMO)与非磁性的SrNb0.01Ti0.99O3(SNTO)所组成的异质结中所存在的正磁电阻效应,同时揭示了该体系中LSMO在界面区域的载流子与远离界面区域的载流子具有不同的自旋极化方向.这一结果将为理解钙钛矿氧化物异质结及多层膜的自旋极化输运机制开辟了一条新的途径. 相似文献
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自旋极化扫描隧道显微镜(spin-polarized scanning tunneling microscope,SP-STM)将扫描隧道显微镜(scanning tunneling microscope,STM)的实空间分辨率和对自旋敏感的磁成像技术结合起来,已经成为人们研究纳米磁性物理的最有效工具之一.文章介绍了SP-STM的工作原理及其在低维磁性物理领域的应用和最新进展,如对磁性薄膜、磁性纳米岛、磁性原子及不共线结构的研究等,并对我国在这一领域的研究现状和发展前景进行简要评述. 相似文献
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R. Gebarowski P. Šeba K. Życzkowski J. Zakrzewski 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,6(3):399-409
Quantum scattering is studied in a system consisting of randomly distributed point scatterers in the strip. The model is continuous
yet exactly solvable. Varying the number of scatterers (the sample length) we investigate a transition between the ballistic
and the localized regimes. By considering the cylinder geometry and introducing the magnetic flux we are able to study time
reversal symmetry breaking in the system. Both macroscopic (conductance) and microscopic (eigenphases distribution, statistics
of S-matrix elements) characteristics of the system are examined.
Received: 28 January 1998 / Revised: 16 June 1998 / Accepted: 6 July 1998 相似文献
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F. Russo G. Carapella V. Granata N. Martucciello G. Costabile 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,60(1):61-66
The magnetoresistance of several Ferromagnet/Normal
metal/Ferromagnet spin-valve type structures has been investigated using Al
as normal spacer layer. A magnetoresistance ratio up to 4.1% at room
temperature and 5.7% at 0.3 K is found for the sandwich with both Co
layers, while slightly lower signals are found for the structures involving
CoFe and NiFe layers. The magnetoresistance dependence for Co/Al/Co,
Co/Al/CoFe and Co/Al/NiFe on the spacer layer thickness exhibits the
familiar non monotonic behaviour with second peak slightly larger than the
one reported for Cu based pseudo spin valves. At cryogenic temperatures,
preliminary results on the onset of spin switch effects in Co/Al/Co and the
full spin switch effect in Co/Nb/Co are also reported here. 相似文献
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The thermoelectric power generated in magnetic tunnel junctions (MTJs) is determined as a function of the tunnel barrier thickness for a matched electric circuit. This study suggests that lower resistance area product and higher tunnel magnetoresistance will maximize the thermoelectric power output of the MTJ structures. Further, the thermoelectric behavior of a series of two MTJs, a MTJ thermocouple, is investigated as a function of its magnetic configurations. In an alternating magnetic configurations the thermovoltages cancel each other, while the magnetic contribution remains. A large array of MTJ thermocouples could amplify the magnetic thermovoltage signal significantly. 相似文献
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F. Romeo R. Citro 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,50(3):483-489
We study the spin polarized currents generation in a magnetic
(ferromagnetic/ferromagnetic) tunnel junction by means of
adiabatic quantum pumping. Using a scattering matrix approach, it
is shown that a pure spin current can be pumped from one
ferromagnetic lead into the adjacent one by adiabatic modulation
of the magnetization and the height of the barrier at the
interface in absence of external bias voltage. We numerically
study the characteristic features of the pure spin current and
discuss its behavior for realistic values of the parameters. We
show that the generated pure spin current is robust with respect
to the variation of the magnetization strength, a very important
feature for a realistic device, and that the proposed device can
operate close to the optimal pumping regime. An experimental
realization of a pure spin current injector is also discussed. 相似文献
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A generalized finite element formulation is proposed for the study of the spin-dependent ballistic transport of electron through the two-dimensional quantum structures with Rashba spin-orbit interactions (SOI). Thetransmission coefficient, conductance, the total and local polarization are numerically calculated and discussed as the Rashba coefficient, the geometric sizes, and incident energy are changed in the T-shaped devices. Some interesting features are found in the proper parameter regime. The polarization has an enhancement as the Rashba coefficient becomes stronger. The polarization valley is rigid in the regime of the conductance plateaus since the local interference among the polarized multi-wave modes. The Rashba interactions coupling to geometry in sizes could form the structure-induced Fano-Rashba resonance. In the wider stub, the localized spin lattice of electron could be produced. The conductance plateaus correspond to weakpolarizations. Strong polarizations appear when the stub sizes, incident energy, and the Rashba coupling coefficient are matched. The resonances are formed in a wide Fermi energy segment easily. 相似文献
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In this article, we review the recent progress in growth, structural characterizations, magnetic properties, and related spintronic devices of tetragonal MnxGa and MnxA1 thin films with perpendicular magnetic anisotropy. First, we present a brief introduction to the demands for perpendicularly magnetized materials in spintronics, magnetic recording, and perma- nent magnets applications, and the most promising candidates of tetragonal MnxGa and MnxA1 with strong perpendicular magnetic anisotropy. Then, we focus on the recent progress of perpendicularly magnetized MnxGa and MnxA1 respec- tively, including their lattice structures, bulk synthesis, epitaxial growth, structural characterizations, magnetic and other spin-dependent properties, and spintronic devices like magnetic tunneling junctions, spin valves, and spin injectors into semiconductors. Finally, we give a summary and a perspective of these perpendicularly magnetized Mn-based binary alloy films for future applications. 相似文献