Spin dynamics in van der Waals magnetic systems

Tang, Chunli; Alahmed, Laith; Mahdi, Muntasir; Xiong, Yuzan; Inman, Jerad; McLaughlin, Nathan J.; Zollitsch, Christoph; Kim, Tae Hee; Du, Chunhui Rita; Kurebayashi, Hidekazu; Santos, Elton J.G.; Zhang, Wei; Li, Peng; Jin, Wencan

doi:10.1016/j.physrep.2023.09.002

Cited by 17 publications

(6 citation statements)

References 270 publications

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“…The numerical simulations were performed using the Mumax3 solver, which allowed larger simulation sizes relative to atomistic spin dynamics. ,− ,− Regions of in-plane and out-of-plane anisotropy comprised of Thiessen polygons were generated with Voronoi tessellation, using a grain size of 200 nm. The material parameters were chosen to be exchange constant A = 10 pJ m –1 , Gilbert damping α = 0.3, saturation magnetization M s = 630 kA m –1 along c -axis, M s = 730 kA m –1 along ab -plane, and D = 1.2 mJ m –2 and K u = 2.5 kJ m –3 in the out-of-plane regions, and periodic boundary conditions were applied in the lateral film dimensions.…”

Section: Methods and Experimental Detailsmentioning

confidence: 99%

Writing and Detecting Topological Charges in Exfoliated Fe_5–xGeTe₂

Moon,

Li,

McKeever

et al. 2024

ACS Nano

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Fe 5−x GeTe 2 is a promising two-dimensional (2D) van der Waals (vdW) magnet for practical applications, given its magnetic properties. These include Curie temperatures above room temperature, and topological spin textures�TST (both merons and skyrmions), responsible for a pronounced anomalous Hall effect (AHE) and its topological counterpart (THE), which can be harvested for spintronics. Here, we show that both the AHE and THE can be amplified considerably by just adjusting the thickness of exfoliated Fe 5−x GeTe 2 , with THE becoming observable even in zero magnetic field due to a fieldinduced unbalance in topological charges. Using a complementary suite of techniques, including electronic transport, Lorentz transmission electron microscopy, and micromagnetic simulations, we reveal the emergence of substantial coercive fields upon exfoliation, which are absent in the bulk, implying thickness-dependent magnetic interactions that affect the TST. We detected a "magic" thickness t ≈ 30 nm where the formation of TST is maximized, inducing large magnitudes for the topological charge density (∼6.45 × 10 20 cm −2 ), and the concomitant anomalous (ρ xy A,max ≃22.6 μΩ cm) and topological (ρ xy u,T 1≃5 μΩ cm) Hall resistivities at T ≈ 120 K. These values for ρ xy A,max and ρ xy u,T are higher than those found in magnetic topological insulators and, so far, the largest reported for 2D magnets. The hitherto unobserved THE under zero magnetic field could provide a platform for the writing and electrical detection of TST aiming at energy-efficient devices based on vdW ferromagnets.

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Section: Methods and Experimental Detailsmentioning

confidence: 99%

Writing and Detecting Topological Charges in Exfoliated Fe_5–xGeTe₂

Moon,

Li,

McKeever

et al. 2024

ACS Nano

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“…Given the ongoing trend towards downscaling in the design of spintronic devices, the coexistence of sp and sp 2 hybridization in graphyne also opens up a new platform for inserting magnetic centers on hexagonal rings similar to that in graphene [34,35], while the sp hybridized carbon atoms can bridge the magnetic centers, carrying and mediating the spin information. This concept differs from manipulating the collective spin states of layered materials [36][37][38]. As an alternative strategy, achieving spin-dynamic processes (both local spin flip and global spin transfer) on or between the deposited magnetic centers can help to further miniaturize spin-logic units.…”

Section: Introductionmentioning

confidence: 99%

Designing spintronic devices in two-dimensional γ-graphyne: from ultrafast spin dynamics to logic applications

Xu(徐帅),

Xie(谢昊),

Zhang(张一鸣)

et al. 2024

J. Phys. D: Appl. Phys.

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The integration of two-dimensional (2D) materials into spintronics represents a frontier in the development of novel computational devices. In this work, by utilizing ab initio many-body theory, we investigate the spin dynamics within the Co-doped γ-graphyne structure, with a particular emphasis on the role of cobalt atoms as magnetic centers. The result reveals that each cobalt atom on the γ-graphyne hosts states with enough spin-density localization to facilitate both local spin flips and global spin transfers. The spin-dynamic processes in our study are characterized by ultrafast time scales and high fidelities, demonstrating efficient spin control in the system. Building upon these spin dynamics processes, we theoretically construct a spin-based Reset-Set (RS) latch, thus demonstrating the feasibility of sophisticated logic operations in our system. Such spin-based devices exhibit the advantages of nano-spintronics over conventional-electronic approaches, offering lower energy consumption, faster operational speeds, and greater potential for miniaturization. The results highlight the efficacy of γ-graphyne nanoflakes doped with cobalt atoms as spin-information processing units, signifying a pivotal advancement in the incorporation of graphyne-based materials into sophisticated spintronic devices. This research paves the way for their application in areas such as data storage, quantum computing, and the development of complex logic-processing architectures.

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“…Layered magnets constitute an important class of compounds renowned for their unconventional physical properties. , The current interest in such materials is spurred by the discovery of two-dimensional (2D) magnetism in a few monolayers (ML) of layered materials. , 2D magnets hold high promise for new quantum phases and applications in ultracompact spintronics. − Their functionality benefits from the high amenability of 2D magnetism to external stimuli such as magnetic and electric fields or pressure . This property extends to multilayer materials; in particular, pressure may readily control the interlayer magnetic coupling .…”

Section: Introductionmentioning

confidence: 99%

Engineering of a Layered Ferromagnet via Graphitization: An Overlooked Polymorph of GdAlSi

Averyanov,

Sokolov,

Taldenkov

et al. 2024

J. Am. Chem. Soc.

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Layered magnets are stand-out materials because of their range of functional properties that can be controlled by external stimuli. Regretfully, the class of such compounds is rather narrow, prompting the search for new members. Graphitizationstabilization of layered graphitic structures in the 2D limitis being discussed for cubic materials. We suggest the phenomenon to extend beyond cubic structures; it can be employed as a viable route to a variety of layered materials. Here, the idea of graphitization is put into practice to produce a new layered magnet, GdAlSi. The honeycomb material, based on graphene-like layers AlSi, is studied both experimentally and theoretically. Epitaxial films of GdAlSi are synthesized on silicon; the critical thickness for the stability of the layered polymorph is around 20 monolayers. Notably, the layered polymorph of GdAlSi demonstrates ferromagnetism, in contrast to the nonlayered, tetragonal polymorph. The ferromagnetism is further supported by electron transport measurements revealing negative magnetoresistance and the anomalous Hall effect. The results show that graphitization can be a powerful tool in the design of functional layered materials.

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Spin dynamics in van der Waals magnetic systems

Cited by 17 publications

References 270 publications

Writing and Detecting Topological Charges in Exfoliated Fe_5–xGeTe₂

Writing and Detecting Topological Charges in Exfoliated Fe_5–xGeTe₂

Designing spintronic devices in two-dimensional γ-graphyne: from ultrafast spin dynamics to logic applications

Engineering of a Layered Ferromagnet via Graphitization: An Overlooked Polymorph of GdAlSi

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Spin dynamics in van der Waals magnetic systems

Cited by 17 publications

References 270 publications

Writing and Detecting Topological Charges in Exfoliated Fe5–xGeTe2

Writing and Detecting Topological Charges in Exfoliated Fe5–xGeTe2

Designing spintronic devices in two-dimensional γ-graphyne: from ultrafast spin dynamics to logic applications

Engineering of a Layered Ferromagnet via Graphitization: An Overlooked Polymorph of GdAlSi

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Product

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Writing and Detecting Topological Charges in Exfoliated Fe_5–xGeTe₂

Writing and Detecting Topological Charges in Exfoliated Fe_5–xGeTe₂