Collective dynamics of domain walls: An antiferromagnetic spin texture in an optical cavity

AbstractMagnetic topological defects can store and carry information. Replacement of extended defects, such as domain walls and Skyrmion tubes, by compact magnetic particles that can propagate in all three spatial directions may open an extra dimension in the design of magnetic memory and data processing devices. We show that such objects can be found in iron langasite, which exhibits a hierarchy of non-collinear antiferromagnetic spin structures at very different length scales. We derive an effective model describing long-distance magnetic modulations in this chiral magnet and find unusual two- and three-dimensional topological defects. The order parameter space of our model is similar to that of superfluid 3He-A, and the particle-like magnetic defect is closely related to the Shankar monopole and hedgehog soliton in the Skyrme model of baryons. Mobile magnetic particles stabilized in non-collinear antiferromagnets can play an important role in antiferromagnetic spintronics.

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Momentum-space and real-space Berry curvatures in Mn$_{3}$Sn

10.21468/scipostphys.5.6.063 ◽

2018 ◽

Vol 5 (6) ◽

Cited By ~ 8

Author(s):

Xiaokang Li ◽

Liangcai Xu ◽

Huakun Zuo ◽

Alaska Subedi ◽

Zengwei Zhu ◽

...

Keyword(s):

Hall Effect ◽

Momentum Space ◽

Domain Walls ◽

Indirect Evidence ◽

Anomalous Hall Effect ◽

Real Space ◽

Distinct Component ◽

Berry Curvature ◽

Moderate Magnetic Field ◽

Spin Texture

Mn_{3}3X (X= Sn, Ge) are noncollinear antiferromagnets hosting a large anomalous Hall effect (AHE). Weyl nodes in the electronic dispersions are believed to cause this AHE, but their locus in the momentum space is yet to be pinned down. We present a detailed study of the Hall conductivity tensor and magnetization in Mn_{3}3Sn crystals and find that in the presence of a moderate magnetic field, spin texture sets the orientation of the kk-space Berry curvature with no detectable in-plane anisotropy due to the Z_6Z6 symmetry of the underlying lattice. We quantify the energy cost of domain nucleation and show that the multidomain regime is restricted to a narrow field window. Comparing the field dependence of AHE and magnetization, we find that there is a distinct component in the AHE which does not scale with magnetization when the domain walls are erected. This so-called ‘topological’ Hall effect provides indirect evidence for a non-coplanar spin components and real-space Berry curvature in domain walls.

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Tunable chiral spin texture in magnetic domain-walls

Scientific Reports ◽

10.1038/srep05248 ◽

2014 ◽

Vol 4 (1) ◽

Cited By ~ 63

Author(s):

J. H. Franken ◽

M. Herps ◽

H. J. M. Swagten ◽

B. Koopmans

Keyword(s):

Domain Walls ◽

Magnetic Domain ◽

Magnetic Domain Walls ◽

Spin Texture

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Imaging non-collinear antiferromagnetic textures via single spin relaxometry

Nature Communications ◽

10.1038/s41467-021-20995-x ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Aurore Finco ◽

Angela Haykal ◽

Rana Tanos ◽

Florentin Fabre ◽

Saddem Chouaieb ◽

...

Keyword(s):

Domain Walls ◽

Nitrogen Vacancy ◽

Magnetic Noise ◽

Laser Illumination ◽

Single Spin ◽

Antiferromagnetic Materials ◽

All Optical ◽

Nanoscale Imaging ◽

Antiferromagnetic Spin ◽

Experimental Challenge

AbstractAntiferromagnetic materials are promising platforms for next-generation spintronics owing to their fast dynamics and high robustness against parasitic magnetic fields. However, nanoscale imaging of the magnetic order in such materials with zero net magnetization remains a major experimental challenge. Here we show that non-collinear antiferromagnetic spin textures can be imaged by probing the magnetic noise they locally produce via thermal populations of magnons. To this end, we perform nanoscale, all-optical relaxometry with a scanning quantum sensor based on a single nitrogen-vacancy (NV) defect in diamond. Magnetic noise is detected through an increase of the spin relaxation rate of the NV defect, which results in an overall reduction of its photoluminescence signal under continuous laser illumination. As a proof-of-concept, the efficiency of the method is demonstrated by imaging various spin textures in synthetic antiferromagnets, including domain walls, spin spirals and antiferromagnetic skyrmions. This imaging procedure could be extended to a large class of intrinsic antiferromagnets and opens up new opportunities for studying the physics of localized spin wave modes for magnonics.

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Antiferromagnetic switching driven by the collective dynamics of a coexisting spin glass

Science Advances ◽

10.1126/sciadv.abd8452 ◽

2021 ◽

Vol 7 (2) ◽

pp. eabd8452

Author(s):

Eran Maniv ◽

Nityan L. Nair ◽

Shannon C. Haley ◽

Spencer Doyle ◽

Caolan John ◽

...

Keyword(s):

Spin Glass ◽

Broken Symmetry ◽

Antiferromagnetic Order ◽

Antiferromagnetic State ◽

Electrical Switching ◽

Collective Dynamics ◽

Local Texture ◽

New Material ◽

Antiferromagnetic Spin

The theory behind the electrical switching of antiferromagnets is premised on the existence of a well-defined broken symmetry state that can be rotated to encode information. A spin glass is, in many ways, the antithesis of this state, characterized by an ergodic landscape of nearly degenerate magnetic configurations, choosing to freeze into a distribution of these in a manner that is seemingly bereft of information. Here, we show that the coexistence of spin glass and antiferromagnetic order allows a novel mechanism to facilitate the switching of the antiferromagnet Fe1/3 + δNbS2, rooted in the electrically stimulated collective winding of the spin glass. The local texture of the spin glass opens an anisotropic channel of interaction that can be used to rotate the equilibrium orientation of the antiferromagnetic state. Manipulating antiferromagnetic spin textures using a spin glass’ collective dynamics opens the field of antiferromagnetic spintronics to new material platforms with complex magnetic textures.

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The direct determination of magnetic domain wall profiles using a split detector STEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100109471 ◽

1978 ◽

Vol 36 (1) ◽

pp. 466-467

Author(s):

J.N. Chapman ◽

P.E. Batson ◽

E.M. Waddell ◽

R.P. Ferrier

Keyword(s):

Electron Microscope ◽

Domain Wall ◽

Transmission Electron Microscope ◽

Domain Walls ◽

Photographic Plate ◽

Magnetic Domain ◽

Direct Determination ◽

Quantitative Information ◽

Scanning Transmission Electron Microscope ◽

Transmission Electron

By far the most commonly used mode of Lorentz microscopy in the examination of ferromagnetic thin films is the Fresnel or defocus mode. Use of this mode in the conventional transmission electron microscope (CTEM) is straightforward and immediately reveals the existence of all domain walls present. However, if such quantitative information as the domain wall profile is required, the technique suffers from several disadvantages. These include the inability to directly observe fine image detail on the viewing screen because of the stringent illumination coherence requirements, the difficulty of accurately translating part of a photographic plate into quantitative electron intensity data, and, perhaps most severe, the difficulty of interpreting this data. One solution to the first-named problem is to use a CTEM equipped with a field emission gun (FEG) (Inoue, Harada and Yamamoto 1977) whilst a second is to use the equivalent mode of image formation in a scanning transmission electron microscope (STEM) (Chapman, Batson, Waddell, Ferrier and Craven 1977), a technique which largely overcomes the second-named problem as well.

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