Electrical Detection of Spin Accumulation at a Ferromagnet-Semiconductor Interface

Lou, Xudong; Adelmann, Christoph; Furis, Madalina; Crooker, S. A.; Palmstrøm, C. J.; Crowell, P. A.

doi:10.1103/physrevlett.96.176603

Cited by 188 publications

(195 citation statements)

References 26 publications

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“…Spin accumulation and precession directly under the magnetic tunnel barrier contact interface can be observed using a single contact for both spin injection and detection 11,12,15 . This measurement configuration uses three terminals-two reference and one FM injector/detector, as shown in Figure 1.…”

Section: Measuring Spin Accumulationmentioning

confidence: 99%

Electrical injection and detection of spin accumulation in silicon at 500 K with magnetic metal/silicon dioxide contacts

2011

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The International Technology Roadmap for semiconductors has identified the electron's spin angular momentum as a new state variable that should be explored as an alternative to the electron's charge for use beyond the size scaling of moore's Law. A major obstacle has been achieving control of the spin variable at temperatures required for practical applications. Here we demonstrate electrical injection, detection and precession of spin accumulation in silicon, the cornerstone material of device technology, at temperatures that easily exceed these requirements. We observe Hanle precession of electron spin accumulation in silicon for a wide range of bias, show that the magnitude of the Hanle signal agrees well with theory, and that the spin lifetime varies with silicon carrier density. These results confirm spin accumulation in the silicon transport channel to 500 K rather than trapping in localized interface states, and enable utilization of the spin variable in practical device applications.

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Section: Measuring Spin Accumulationmentioning

confidence: 99%

Electrical injection and detection of spin accumulation in silicon at 500 K with magnetic metal/silicon dioxide contacts

2011

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“…In the Datta-Das device, the spinpolarized current which flows in the semiconductor channel, often supposed as a 2-dimensional electron gas (2DEG), is manipulated by electrostatic gate-action, hence providing electrical control of the source-drain current in addition to that provided by the relative alignment of the ferromagnetic contacts. To this end, imaging of the injected spin-polarization from Fe into n-GaAs has been performed in a lateral geometry by Crooker et al 11 and in a cross-sectional geometry by Kotissek et al 12 , whilst Lou et al 13 and Lou et al 14 have demonstrated all-electrical measurements of spin-injection, -transport and -detection in a single Fe/GaAs(001) device. Garlid et al 15 have also used Fe/InGaAs(001) contacts to measure the transverse spin-current generated via the spin-Hall effect.…”

Section: Introductionmentioning

confidence: 99%

Interface Magnetism in Ferromagnetic Metal–compound Semiconductor Hybrid Structures

Hindmarch

2011

SPIN

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Interfaces between dissimilar materials present a wide range of fascinating physical phenomena. When a nanoscale thin-film of a ferromagnetic metal is deposited in intimate contact with a compound semiconductor, the properties of the interface exhibit a wealth of novel behavior, having immense potential for technological application, and being of great interest from the perspective of fundamental physics. This article presents a review of recent advances in the field of interface magnetism in (001)-oriented ferromagnetic metal/III–V compound semiconductor hybrid structures. Until relatively recently, the majority of research in this area continued to concentrate almost exclusively on the prototypical epitaxial Fe / GaAs (001) system: now, a significant proportion of work has branched out from this theme, including ferromagnetic metal alloys, and other III–V compound semiconductors. After a general overview of the topic, and a review of the more recent literature, we discuss recent results where advances have been made in our understanding of the physics underpinning magnetic anisotropy in these systems: tailoring the terms contributing to the angular-dependent free-energy density by employing novel fabrication methods and ferromagnetic metal electrodes.

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“…This signal can be in the form of a voltage change or a torque acting on the magnetization of the ferromagnet (FM). In practice, this raises technical difficulties due the conductance mismatch [17] that can be solved [18] and are not addressed here. We rather focus on conceptual problems that are related to the voltage and torque signals generated by current-induced spins [19].…”

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confidence: 99%

Detection of Current-Induced Spins by Ferromagnetic Contacts

2006

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Detection of current-induced spin accumulation via ferromagnetic contacts is discussed. Onsager's relations forbid that in a two-probe configuration, spins excited by currents in time-reversal symmetric systems can be detected by switching the magnetization of a ferromangetic detector contact. Nevertheless, current-induced spins can be transferred as a torque to a contact magnetization and can affect the charge currents in many-terminal configurations. We demonstrate the general concepts by solving the microscopic transport equations for the diffuse Rashba system with magnetic contacts. DOI: 10.1103/PhysRevLett.97.256601 PACS numbers: 72.25.Dc, 72.20.Dp, 72.25.Mk The notion that netto spin distributions can be generated by electric currents in the bulk of nonmagnetic semiconductors with intrinsic spin-orbit (SO) interaction has been predicted [1,2] and experimentally confirmed [3]. The related spin-Hall effect, causing accumulations of spins at the edges, has also been observed [4]. It can be extrinsic, i.e., caused by impurities with SO scattering [5,6] or intrinsic due to an SO split band structure [7,8]. However, all experiments to date detected the current-induced spins optically [16]. An important remaining challenge for theory and experiment is to find ways to transform the novel spin accumulation (SA) and spin currents (SCs) into voltage differences and charge currents in micro-or nanoelectronic circuits in order to fulfill the promises of spintronics.In this Letter, we address the possibility to generate a spin-related signal to be picked up by ferromagnetic contacts. This signal can be in the form of a voltage change or a torque acting on the magnetization of the ferromagnet (FM). In practice, this raises technical difficulties due the conductance mismatch [17] that can be solved [18] and are not addressed here. We rather focus on conceptual problems that are related to the voltage and torque signals generated by current-induced spins [19]. The Onsager relations for the conductance [20] forbid voltage based detection of current-induced spins by a ferromagnetic lead in a two-probe setup within linear response. We sketch a microscopic picture of the physics and formulate a semiclassical scheme in the diffuse limit. We address spin detection in a multiprobe geometry, calculate the Hall conductivity, and compare it to the anomalous Hall effect. We also discuss the possibility to construct spin filters not based on FMs, but on conductors with spatially modulated SO interactions.We first address the symmetry properties in terms of the Onsager relations for the (linear) conductance [20 -23]. A generic SO-Hamiltonian H involves products of velocity and spin operators that are invariant under time reversal. Even when spin-degenerate bands are split due to a broken inversion symmetry, the Kramers degeneracy remains intact. The Hamiltonian of the combined SOjF system has the symmetry TH m T ÿ1 H ÿm , where m is a unit vector in the direction of the magnetization of the FM and T the time-reversal operator. We n...

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Electrical Detection of Spin Accumulation at a Ferromagnet-Semiconductor Interface

Cited by 188 publications

References 26 publications

Electrical injection and detection of spin accumulation in silicon at 500 K with magnetic metal/silicon dioxide contacts

Electrical injection and detection of spin accumulation in silicon at 500 K with magnetic metal/silicon dioxide contacts

Interface Magnetism in Ferromagnetic Metal–compound Semiconductor Hybrid Structures

Detection of Current-Induced Spins by Ferromagnetic Contacts

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