Silicon spintronics with ferromagnetic tunnel devices

Jansen, R.; Dash, Saroj P.; Sharma, Sandeep; Min, Byoung‐Chul

doi:10.1088/0268-1242/27/8/083001

Cited by 140 publications

(164 citation statements)

References 146 publications

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“…Three-terminal magnetoresistance (3T MR) in ferromagnet-nonmagnet (FM-NM) tunnel junctions has developed into an important phase-sensitive characterization tool for the rapid identification of materials that can transport spin information over long distances, a crucial feature for spintronic devices [1][2][3][4][5]. In principle, spin injection from a FM electrode and detection of the resulting spin accumulation in a NM semiconductor can be achieved using a single FM electrode in a FM-I-NM structure [1,5], as first demonstrated in n-GaAs [6].…”

Section: Introductionmentioning

confidence: 99%

Origin of the Magnetoresistance in Oxide Tunnel Junctions Determined through Electric Polarization Control of the Interface

et al. 2015

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The observed magnetoresistance (MR) in three-terminal (3T) ferromagnet-nonmagnet (FM-NM) tunnel junctions has historically been assigned to ensemble dephasing (Hanle effect) of a spin accumulation, thus offering a powerful approach for characterizing the spin lifetime of candidate materials for spintronics applications. However, due to crucial discrepancies of the extracted spin parameters with known materials properties, this interpretation has come under intense scrutiny. By employing epitaxial artificial dipoles as the tunnel barrier in oxide heterostructures, the band alignments between the FM and NM channels can be controllably engineered, providing an experimental platform for testing the predictions of the various spin accumulation models. Using this approach, we have been able to definitively rule out spin accumulation as the origin of the 3T MR. Instead, we assign the origin of the magnetoresistance to spin-dependent hopping through defect states in the barrier, a fundamental phenomenon seen across diverse systems. A theoretical framework is developed that can account for the signal amplitude, linewidth, and anisotropy.

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Section: Introductionmentioning

confidence: 99%

Origin of the Magnetoresistance in Oxide Tunnel Junctions Determined through Electric Polarization Control of the Interface

et al. 2015

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“…On the other hand, spin lifetimes in metals obtained by 3T measurements are significantly longer than theoretically predicted 17 . Several experiments also proposed an enhancement 15,18 or inversion 8 of the 3T spin signal, whereas multiple control experiments rule out any enhancement due to interface states 6,16,19 . Therefore, it is required to understand the contributing factors in both techniques by performing experiments in the NL and 3T configuration using the same magnetic tunnel contacts.…”

mentioning

confidence: 99%

Spin transport and precession in graphene measured by nonlocal and three-terminal methods

Dankert

Kamalakar

Bergsten

et al. 2014

Applied Physics Letters

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We investigate the spin transport and precession in graphene by using the Hanle effect in nonlocal and threeterminal measurement geometries. Identical spin lifetimes, spin diffusion lengths and spin polarizations are observed in graphene devices for both techniques over a wide range of temperatures. The magnitude of the spin signals is well explained by spin transport models. These observations rules out any signal enhancements or additional scattering mechanisms at the interfaces for both geometries. This validates the applicability of both the measurement methods for graphene based spintronics devices and their reliable extractions of spin parameters.Keywords: Graphene, Hanle, Nonlocal, Three-Terminal, Spintronics, Spin transportThe spin degree of freedom of electrons is considered as an alternative state variable for processing information beyond the charge based CMOS technology. Its potential lies in the possibilities for a new generation of computers that can be non-volatile, faster, smaller, and capable of simultaneous data storage and processing with a reduced energy consumption 1. The strong interest in graphene and silicon based spintronic devices stems from their potentially long spin coherence lengths due to the absence of hyperfine interactions and a weak spin-orbit coupling. Such materials could be employed in the recently proposed concept of all spin logic using spins in ferromagnets to store information and communicate between them using a spin current 2 . All spin logic is particularly powerful since it combines various spin related phenomena such as spin injection, transport and detection with magnetization dynamics.In order to achieve these goals various methods for electrical spin injection and detection in metals 3, semiconductors [4][5][6] and graphene 7 have been investigated. Primarily nonlocal (NL) and three-terminal (3T) methods are used for an electrical detection of the spin polarization [6][7][8][9] . The non-local geometry separates the current and voltage path to provide information about pure spin transport parameters. However, nanofabrication by electron beam lithography is necessary in order to achieve submicrometer structures and channel lengths 7 . Although the NL method has been widely used for spin transport measurements in more conducting metals

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“…Especially in semiconductor (SC) spintronics [5][6][7][8] , where the injection, control, and detection of nonequilibrium spin populations (i.e. spin accumulation) in non-magnetic SCs are the main building blocks [5][6][7][8][9] , the functional use of heat provides a new route to inject and control the spin accumulation in SCs without a charge current 4,7,8 .…”

mentioning

confidence: 99%

Thermal spin injection and accumulation in CoFe/MgO tunnel contacts to n-type Si through Seebeck spin tunneling

Jeon

Min

Park

et al. 2013

Applied Physics Letters

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Silicon spintronics with ferromagnetic tunnel devices

Cited by 140 publications

References 146 publications

Origin of the Magnetoresistance in Oxide Tunnel Junctions Determined through Electric Polarization Control of the Interface

Origin of the Magnetoresistance in Oxide Tunnel Junctions Determined through Electric Polarization Control of the Interface

Spin transport and precession in graphene measured by nonlocal and three-terminal methods

Thermal spin injection and accumulation in CoFe/MgO tunnel contacts to n-type Si through Seebeck spin tunneling

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