Combined spin filtering actions in hybrid magnetic junctions based on organic chains covalently attached to graphene

Martin, Pascal; Dlubak, Bruno; Mattana, R.; Sénéor, Pierre; Martin, Marie‐Blandine; Henner, Theo; Godel, Florian; Sander, Anke; Collin, Sophie; Chen, Linsai; Suffit, Stéphan; Mallet, François; Lafarge, P.; Rocca, Maria Luisa Della; Droghetti, Andrea; Barraud, Clément

doi:10.1039/d2nr01917e

Cited by 5 publications

(3 citation statements)

References 83 publications

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“…A variety of devices have been demonstrated including spin valves, spin memory devices, and light-emitting diodes (7)(8)(9). It is expected that the spinterfaces between organic semiconductors and ferromagnetic (FM) metals, which are sensitive to structural properties and side chain substitution of the molecules, play an important role in these spintronic devices (10)(11)(12)(13)(14). However, there are still several obstacles lying ahead for fully understanding these molecular spinterfaces from the experimental point of view, thus limiting the device applications based on organic materials.…”

Section: Introductionmentioning

confidence: 99%

Revealing the key role of molecular packing on interface spin polarization at two-dimensional limit in spintronic devices

et al. 2023

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Understanding spinterfaces between magnetic metals and organic semiconductors is essential to unlock the great potentials that organic materials host for spintronic applications. Although plenty of efforts have been devoted to studying organic spintronic devices, exploring the role of metal/molecule spinterfaces at two-dimensional limit remains challenging because of excessive disorders and traps at the interfaces. Here, we demonstrate atomically smooth metal/molecule interfaces through nondestructively transferring magnetic electrodes on epitaxial grown single-crystalline layered organic films. Using such high-quality interfaces, we investigate spin injection of spin-valve devices based on organic films of different layers, in which molecules are packed in different manners. We find that the measured magnetoresistance and the estimated spin polarization increase markedly for bilayer devices compared with their monolayer counterparts. These observations reveal the key role of molecular packing on spin polarization, which is supported by density functional theory calculations. Our findings provide promising routes toward designing spinterfaces for organic spintronic devices.

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Section: Introductionmentioning

confidence: 99%

Revealing the key role of molecular packing on interface spin polarization at two-dimensional limit in spintronic devices

et al. 2023

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“…[21] Long-term passivation of FMs such as Ni and Co by direct chemical vapor deposition (CVD) of graphene has also been reported, [27] and used as electrodes in magnetic tunnel junctions. [28][29][30] In fact, the interaction between the graphene and the FM leads to hybridization (chemisorption or physisorption), both potentially useful for spintronic applications. [31] In addition, although TI/graphene/ FM heterostructures have not been investigated experimentally, giant CSI and large SOTs have been predicted.…”

Section: Introductionmentioning

confidence: 99%

Passivation of Bi₂Te₃ Topological Insulator by Transferred CVD‐Graphene: Toward Intermixing‐Free Interfaces

Galceran

Bonell

Camosi

et al. 2022

Adv Materials Inter

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The investigation, and ultimate application, of topological insulators, typically involve exposure to ambient conditions or their integration with metals, which lead to surface oxidation or material intermixing. X‐ray photoelectron spectroscopy (XPS) measurements that demonstrate passivated and intermixing‐free interfaces in the topological insulator Bi2Te3 by means of dry‐transferred CVD graphene are reported. After air exposure, no traces of Bi2Te3 oxidation are found. Furthermore, it is demonstrated that graphene acts as a very efficient metal and chalcogen diffusion barrier in Bi2Te3/graphene/permalloy (Py) heterostructures, which are relevant for spintronics. Such results are in stark contrast with the significant surface degradation observed in bare Bi2Te3 under ambient conditions and the deep BiTe bonding disruption that occurs in Bi2Te3/Py heterostructures. These findings provide a new approach to control and engineer topological insulator interfaces for spintronic applications and a new platform to investigate the combined use of graphene and topological insulator Dirac states.

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“…According to eq , the transport is determined by the coherent transmission of spin-up and -down electrons from one lead, through the central region, to the other lead. The transmission coefficient depends on V because the electronic states may shift in energy under the applied bias (see, for instance, refs and ). Notably, I σ in eq is approximately equal to the area under the transmission coefficient-vs-energy curve inside the energy interval [ E F – eV /2, E F + eV /2], known as bias window.…”

mentioning

confidence: 99%

Half-Metallic Transport and Spin-Polarized Tunneling through the van der Waals Ferromagnet Fe₄GeTe₂

Halder,

Nell,

Sihi

et al. 2024

Nano Lett.

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We examine the coherent spin-dependent transport properties of the van der Waals (vdW) ferromagnet Fe 4 GeTe 2 using density functional theory combined with the nonequilibrium Green's function method. Our findings reveal that the conductance perpendicular to the layers is half-metallic, meaning that it is almost entirely spin-polarized. This property persists from the bulk to a single layer, even under significant bias voltages and with spin−orbit coupling. Additionally, using dynamical mean field theory for quantum transport, we demonstrate that electron correlations are important for magnetic properties but minimally impact the conductance, preserving almost perfect spin-polarization. Motivated by these results, we then study the tunnel magnetoresistance (TMR) in a magnetic tunnel junction consisting of two Fe 4 GeTe 2 layers with the vdW gap acting as an insulating barrier. We predict a TMR ratio of ∼500%, which can be further enhanced by increasing the number of Fe 4 GeTe 2 layers in the junction.

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Combined spin filtering actions in hybrid magnetic junctions based on organic chains covalently attached to graphene

Abstract: Spin filtering effect across hybrid graphene/molecule heterostructures connected by ferromagnetic electrodes.

Cited by 5 publications

References 83 publications

Revealing the key role of molecular packing on interface spin polarization at two-dimensional limit in spintronic devices

Revealing the key role of molecular packing on interface spin polarization at two-dimensional limit in spintronic devices

Passivation of Bi₂Te₃ Topological Insulator by Transferred CVD‐Graphene: Toward Intermixing‐Free Interfaces

Half-Metallic Transport and Spin-Polarized Tunneling through the van der Waals Ferromagnet Fe₄GeTe₂

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Combined spin filtering actions in hybrid magnetic junctions based on organic chains covalently attached to graphene

Abstract: Spin filtering effect across hybrid graphene/molecule heterostructures connected by ferromagnetic electrodes.

Cited by 5 publications

References 83 publications

Revealing the key role of molecular packing on interface spin polarization at two-dimensional limit in spintronic devices

Revealing the key role of molecular packing on interface spin polarization at two-dimensional limit in spintronic devices

Passivation of Bi2Te3 Topological Insulator by Transferred CVD‐Graphene: Toward Intermixing‐Free Interfaces

Half-Metallic Transport and Spin-Polarized Tunneling through the van der Waals Ferromagnet Fe4GeTe2

Contact Info

Product

Resources

About

Passivation of Bi₂Te₃ Topological Insulator by Transferred CVD‐Graphene: Toward Intermixing‐Free Interfaces

Half-Metallic Transport and Spin-Polarized Tunneling through the van der Waals Ferromagnet Fe₄GeTe₂