Non-collinear magnetism induced by frustration in transition-metal nanostructures deposited on surfaces

Lounis, Samir

doi:10.1088/0953-8984/26/27/273201

Cited by 17 publications

(11 citation statements)

References 106 publications

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“…4 a. Here, magnetic frustration stabilizes the previously discussed spin-flop state similar to what was found on ferromagnetic substrates 56 – 59 (see Supplementary Note 3 ). The adatom-adatom and adatom-substrate HEI are simultaneously antiferromagnetic, which lead to a magnetic compromise where the Cr moments are antiferromagnetically aligned with a strong tilt opposite to the surface magnetization.…”

Section: Resultssupporting

confidence: 83%

Sub-nanoscale atom-by-atom crafting of skyrmion-defect interaction profiles

Arjana

Fernandes

Chico

et al. 2020

Sci Rep

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Magnetic skyrmions are prime candidates as information carriers for spintronic devices due to their topological nature and nanometric size. However, unavoidable inhomogeneities inherent to any material leads to pinning or repulsion of skyrmions that, in analogy to biology concepts, define the phenotype of the skyrmion-defect interaction, generating complexity in their motion and challenging their application as future bits of information. Here, we demonstrate that atomby-atom manufacturing of multi-atomic defects, being antiferromagnetic or ferromagnetic, permits the breeding of their energy profiles, for which we build schematically a Punnet-square. As established from first-principles for skyrmions generated in PdFe bilayer on Ir(111) surface, the resulting interaction phenotype is rich. it can be opposite to the original one and eventually be of dual pinning-repulsive nature yielding energy landscapes hosting multi-domains. this is dictated by the stacking site, geometry, size and chemical nature of the adsorbed defects, which control the involved magnetic interactions. this work provides new insights towards the development of disruptive device architectures incorporating defects into their design aiming to control and guide skyrmions. Magnetic skyrmions 1,2 , i.e. non-collinear spin textures with particle-like properties, are promising future magnetic bits for future data storage technologies based on topological concepts 3-11. Of great technological relevance are skyrmions in thin films and magnetic multilayers 12-22 , which can be stabilized as a result of the competition among the Heisenberg exchange interaction (HEI), Dzyaloshinskii-Moriya interaction (DMI) 23,24 and the perpendicular magnetic anisotropy. The low spin polarized current thresholds required to manipulate skyrmions compared to typical ferromagnetic domain walls 3,25 along with their high mobility, high stability and small sizes make them ideal for achieving efficient and functional devices. However, defects that are ineluctable in any device and materials are often seen as inhibitors for applications. The dynamical behavior of the skyrmion motion as function of applied currents hinges on the presence of defects, which define the three motion regimes: pinning, creep-and steady-flow-motion as demonstrated experimentally in ultrathin heavy metal/ferromagnetic bilayers and multilayers 15,26,27. Considerable effort has been performed to explore the dynamics pertaining to current-induced skyrmion motion 3,4,15,28-32 , with a particular attention to the role of defects 33-36. In particular, simulations using realistic parameters extracted from ab-initio showed that by controlling the mutual distance of the pinning defects, one may engineer a double track to guide the skyrmion motion and enhance its velocity 36. Atomic-scale imaging based on scanning tunneling microscopy demonstrated that skyrmions in PdFe bilayer on Ir(111) are inert to the presence of a single Co adatom, in accordance to recent ab-initio simulations 34 , but react to the presence...

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Section: Resultssupporting

confidence: 83%

Sub-nanoscale atom-by-atom crafting of skyrmion-defect interaction profiles

Arjana

Fernandes

Chico

et al. 2020

Sci Rep

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“…Localized magnetic moments can be intrinsic to the sample production process or can be introduced extrinsically, for instance, by implantation with an STM tip. 31,32 This method provides a controlled way of designing magnetic nanostructures. In the case of TMDs, the local moment formation with magnetic dopants has been analyzed by ab-initio studies, 29,[33][34][35] and in experiments.…”

mentioning

confidence: 99%

Symmetries and hybridization in the indirect interaction between magnetic moments inMoS2nanoflakes

2016

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We study the Ruderman-Kittel-Kasuya-Yosida interaction between magnetic impurities embedded in p-doped transition metal dichalcogenide triangular flakes. The role of underlying symmetries is exposed by analyzing the interaction as a function of impurity separation along zigzag and armchair trajectories, in specific parts of the sample. The large spin-orbit coupling in these materials produces strongly anisotropic interactions, including a Dzyaloshinskii-Moriya component that can be sizable and tunable. We consider impurities hybridized to different orbitals of the host transition-metal and identify specific characteristics for onsite and hollow site adsorption. In the onsite case, the different components of the interaction have similar magnitude, while for the hollow site, the Ising component dominates. We also study the dependence of the interaction with the level of hole doping, which supplies a further degree of tunability. Our results could provide ways of controlling helical long range spin order in magnetic impurity arrays embedded in these materials.

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“…This category connects to important molecular examples, such as models of the core of the Photosynthetic Oxygen-Evolving Complex, [1][2][3][4] and also extended-system phenomena like noncollinear magnetism. [5][6][7][8] There are also more subtle reproaches to unchecked UHF usage. For example, tenable theoretical treatments of paramagnetic systems, such as liquid oxygen, 9 require a full range of spin orientations for their radical units.…”

Section: Introductionmentioning

confidence: 99%

A simple way to test for collinearity in spin symmetry broken wave functions: General theory and application to generalized Hartree Fock

Small

Sundstrom

Head‐Gordon

2015

The Journal of Chemical Physics

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We introduce a necessary and sufficient condition for an arbitrary wavefunction to be collinear, i.e., its spin is quantized along some axis. It may be used to obtain a cheap and simple computational procedure to test for collinearity in electronic structure theory calculations. We adapt the procedure for Generalized Hartree Fock (GHF), and use it to study two dissociation pathways in CO2. For these dissociation processes, the GHF wave functions transform from low-spin Unrestricted Hartree Fock (UHF) type states to noncollinear GHF states and on to high-spin UHF type states, phenomena that are succinctly illustrated by the constituents of the collinearity test. This complements earlier GHF work on this molecule.

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Non-collinear magnetism induced by frustration in transition-metal nanostructures deposited on surfaces

Cited by 17 publications

References 106 publications

Sub-nanoscale atom-by-atom crafting of skyrmion-defect interaction profiles

Sub-nanoscale atom-by-atom crafting of skyrmion-defect interaction profiles

Symmetries and hybridization in the indirect interaction between magnetic moments inMoS2nanoflakes

A simple way to test for collinearity in spin symmetry broken wave functions: General theory and application to generalized Hartree Fock

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