共查询到19条相似文献,搜索用时 125 毫秒
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巨磁电阻效应的发现开拓了磁电子学的新领域,20世纪90年代,磁电子学到了迅速的发展,并在实际应用方面取得了显著的经济效益与巨大的社会效益,本世纪初,研究重点已转移到新的半导体自旋电子学方向,并取得了重要进展。本文结合作者率领的科研组的研究工作,阐述了从磁电子学材料到半导体自旋电子学材料的发展概况,其中,重点介绍了稀磁半导体材料的研究进展。 相似文献
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当前的微电子器件主要是通过控制半导体中载流子的电荷来存储、处理和传输信息,电子的自旋自由度长期在这些应用中被忽略。自旋电子学主要是研究与载流子的自旋相关的各种现象和效应,为在微电子器件中集成这些自旋效应,产生各种更新更强的功能的自旋器件奠定基础。有机半导体材料由于自旋轨道作用和超精细作用很弱,自旋扩散长度被认为很长,因而是一种具有很强应用潜力的自旋电子材料。最近,我们研究组首次成功的在低温下,以有机材料Alq_3作为中间层,La_(2/3)Sr_(1/3)MnO_3(LSMO)和Co分别作为两个电极的三明治结构中,低温下获得了高达40%的巨磁电阻效应。磁电阻随有机材料厚度的增加指数衰减,根据修正后的Jullierre模型,自旋扩散长度估计为约45nm。另外,巨磁电阻效应随温度的升高而降低,在温度较高时,样品除了有巨磁电阻效应之外,还明显表现出一种物理机理完全不同的高场磁电阻效应,电阻随磁场的增加而持续降低。为了进一步研究这种高场磁电阻效应的物理机理,我们制备了仅有一个铁磁性电极的有机发光二极管LSMO/有机/Al器件,实验结果表明高场磁阻效应与有机材料和制备方法无关,同时,发光器件的电致发光效应随磁场的增大而... 相似文献
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具有显著Seebeck效应的碳纤维水泥基复合材料(Carbon fiber reinforced cement-based composites,简写为CFRC)近年来受到广泛关注。综述了CFRC的导电机理、Seebeck效应强化途径及其工程应用前景。CFRC的载流子类型主要包括离子、电子和空穴,并以空穴为主。碳纤维/碳纳米管掺杂,CFRC的Seebeck系数可提高至约30μV/℃;钢纤维掺杂水泥基材料表现为n型半导体,其Seebeck可达68μV/℃;金属氧化物Bi_2O_3掺杂可将CFRC的Seebeck系数稳步提高到100.28μV/℃,而ZnO和Fe_2O_3掺杂可使CFRC的Seebeck系数分别增大到3 300μV/℃和2 500μV/℃。这些研究有效地促进了CFRC在城市室外热量的转换收集、工业余热能量收集和长寿命结构健康监测传感器等领域的研究与发展。 相似文献
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关于铁磁金属体系中的自旋热输运实验研究,目前遇到的困难有:温度梯度的不均匀、铁磁金属中自旋流的分布不均匀,以及界面的各种散射等,这都会对铁磁金属多层膜体系的自旋塞贝克效应(SSE)产生显著影响,另外,诸多热相关效应引起的干扰信号,也会导致测量结果不准确。以上问题的存在是相关实验研究很少,且实验结果备受争议的原因。这些问题的解决,对于深入理解自旋热输运过程以及成功将自旋塞贝克效应于自旋电子器件中,均具有重要的理论和实践价值。本工作研究了FM/NM、FM1/FM2/NM结构中的纵向自旋塞贝克效应(LSSE),通过差分方法,扣除了研究体系中FM自身的反常能斯特信号和FM自身所产生的逆自旋霍尔效应信号,从而得到了体系的单一自旋塞贝克效应(SSE)信号。在此基础上,进一步研究了SSE信号对温度及铁磁层厚度的依赖关系。结果表明,SSE信号随温度升高而减小,随厚度增加而增大,值得注意的是,相较于单层FM体系,双层FM体系的信号并非各FM层信号的简单叠加;通过与文献的对比研究发现,采用本实验方法提取的SSE信号与理论模型计算值符合较好。 相似文献
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Haoliang Liu Hans Malissa Ryan M. Stolley Jaspal Singh Matthew Groesbeck Henna Popli Marzieh Kavand Su Kong Chong Vikram V. Deshpande Joel S. Miller Christoph Boehme Z. Valy Vardeny 《Advanced materials (Deerfield Beach, Fla.)》2020,32(39):2002663
Spin waves, quantized as magnons, have low energy loss and magnetic damping, which are critical for devices based on spin-wave propagation needed for information processing devices. The organic-based magnet [V(TCNE)x; TCNE = tetracyanoethylene; x ≈ 2] has shown an extremely low magnetic damping comparable to, for example, yttrium iron garnet (YIG). The excitation, detection, and utilization of coherent and non-coherent spin waves on various modes in V(TCNE)x is demonstrated and show that the angular momentum carried by microwave-excited coherent spin waves in a V(TCNE)x film can be transferred into an adjacent Pt layer via spin pumping and detected using the inverse spin Hall effect. The spin pumping efficiency can be tuned by choosing different excited spin wave modes in the V(TCNE)x film. In addition, it is shown that non-coherent spin waves in a V(TCNE)x film, excited thermally via the spin Seebeck effect, can also be used as spin pumping source that generates an electrical signal in Pt with a sign change in accordance with the magnetization switching of the V(TCNE)x. Combining coherent and non-coherent spin wave detection, the spin pumping efficiency can be thermally controlled, and new insight is gained for the spintronic applications of spin wave modes in organic-based magnets. 相似文献
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利用塞贝克效应研制成功ZnO半导体气敏传感器。这种新型传感器能够输出0-100mV的直流电压,对于信号的放大与处理将十分方便。在实验中对20×10-6NO2气体进行检测,结果表明:传感器的输出电压(温差电动势),随着待测气体浓度而变化。因此,利用温差电效应制作气敏传感器是一条完全可行的新思路。 相似文献
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AbstractNonlocal spin transport in nanostructured devices with ferromagnetic injector (F1) and detector (F2) electrodes connected to a normal conductor (N) is studied. We reveal how the spin transport depends on interface resistance, electrode resistance, spin polarization and spin diffusion length, and obtain the conditions for efficient spin injection, spin accumulation and spin current in the device. It is demonstrated that the spin Hall effect is caused by spin–orbit scattering in nonmagnetic conductors and gives rise to the conversion between spin and charge currents in a nonlocal device. A method of evaluating spin–orbit coupling in nonmagnetic metals is proposed. 相似文献
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Boris Divinskiy Vladislav E. Demidov Sergei Urazhdin Ryan Freeman Anatoly B. Rinkevich Sergej O. Demokritov 《Advanced materials (Deerfield Beach, Fla.)》2018,30(33)
The emerging field of nanomagnonics utilizes high‐frequency waves of magnetization—spin waves—for the transmission and processing of information on the nanoscale. The advent of spin‐transfer torque has spurred significant advances in nanomagnonics, by enabling highly efficient local spin wave generation in magnonic nanodevices. Furthermore, the recent emergence of spin‐orbitronics, which utilizes spin–orbit interaction as the source of spin torque, has provided a unique ability to exert spin torque over spatially extended areas of magnonic structures, enabling enhanced spin wave transmission. Here, it is experimentally demonstrated that these advances can be efficiently combined. The same spin–orbit torque mechanism is utilized for the generation of propagating spin waves, and for the long‐range enhancement of their propagation, in a single integrated nanomagnonic device. The demonstrated system exhibits a controllable directional asymmetry of spin wave emission, which is highly beneficial for applications in nonreciprocal magnonic logic and neuromorphic computing. 相似文献
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We consider the spin-Hall effect in two-dimensional electron systems (2DES) with Rashba and Dresselhaus spin-orbit couplings (SO). We find nonzero diagonal spin conductivity provided that Dresselhaus coupling is finite. In addition we consider the influence of disorder on spin conductivities in these systems. By comparing with the exact diagonalization method the finite quasiparticle lifetime (Born) approximation we argue that the latter one seems to be sufficient to describe the case when spin-orbit coupling is stronger or comparable with disorder strength. Furthermore, in the framework of Landauer–Buttiker formalism we show that the transverse and diagonal spin conductivities in Rashba plus Dresselhaus SO systems are robust against disorder for finite size systems. 相似文献
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本文简述了磁制冷的基本原理,分析磁制冷工质的熵特性,总结了近几年磁制冷材料的最新进展,对磁制冷材料未来的发展进行了展望。 相似文献
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In this paper we demonstrate the possibility of dissipationless spin transport in the chiral d-density wave state, by the sole application of a uniform Zeeman field gradient. The occurrence of these spontaneous spin
currents is attributed to the parity (℘) and time-reversal (
) violation induced by the
density wave order parameter. We calculate the spin Hall conductance and reveal its intimate relation to the Berry phase which
is generated when the Zeeman field is applied adiabatically. Finally, we demonstrate that in the zero temperature and doping
case, the spin Hall conductance is quantized as it becomes a topological invariant.
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