Emergence of the topological Hall effect in a tetragonal compensated ferrimagnet Mn2.3Pd0.7Ga

AbstractTopological spin textures such as magnetic skyrmions have attracted considerable interest due to their potential application in spintronic devices. However, there still remain several challenges to overcome before their practical application, for instance, achieving high scalability and thermal stability. Recent experiments have proposed a new class of skyrmion materials in the Heusler family, Mn1.4Pt0.9Pd0.1Sn and Mn2Rh0.95Ir0.05Sn, which possess noncollinear magnetic structures. Motivated by these experimental results, we suggest another Heusler compound hosted by Mn3Ga to overcome the above limitations. We fabricate Mn3-xPdxGa thin films, focusing on the magnetic compensation point. In Mn2.3Pd0.7Ga, we find a spin-reorientation transition around TSR = 320 K. Below the TSR, we observe the topological Hall effect and a positive magnetic entropy change, which are the hallmarks of a chiral noncollinear spin texture. By integrating all the data, we determine the magnetic phase diagram, displaying a wide chiral noncollinear spin phase even at room temperature. We believe that this compensated ferrimagnet shows promise for opening a new avenue toward chiral spin-based, high-density, and low-power devices.

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Emulating spin transport with nonlinear optics, from high-order skyrmions to the topological Hall effect

Nature Communications ◽

10.1038/s41467-021-21250-z ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Aviv Karnieli ◽

Shai Tsesses ◽

Guy Bartal ◽

Ady Arie

Keyword(s):

Photonic Crystals ◽

Hall Effect ◽

Optical System ◽

Crystal Engineering ◽

Spin Transport ◽

Research Effort ◽

Nonlinear Photonic Crystals ◽

Topological Hall Effect ◽

Magnetic Skyrmions ◽

Quantum Optical

AbstractExploring material magnetization led to countless fundamental discoveries and applications, culminating in the field of spintronics. Recently, research effort in this field focused on magnetic skyrmions – topologically robust chiral magnetization textures, capable of storing information and routing spin currents via the topological Hall effect. In this article, we propose an optical system emulating any 2D spin transport phenomena with unprecedented controllability, by employing three-wave mixing in 3D nonlinear photonic crystals. Precise photonic crystal engineering, as well as active all-optical control, enable the realization of effective magnetization textures beyond the limits of thermodynamic stability in current materials. As a proof-of-concept, we theoretically design skyrmionic nonlinear photonic crystals with arbitrary topologies and propose an optical system exhibiting the topological Hall effect. Our work paves the way towards quantum spintronics simulations and novel optoelectronic applications inspired by spintronics, for both classical and quantum optical information processing.

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Interface-driven topological Hall effect in SrRuO3-SrIrO3 bilayer

Science Advances ◽

10.1126/sciadv.1600304 ◽

2016 ◽

Vol 2 (7) ◽

pp. e1600304 ◽

Cited By ~ 176

Author(s):

Jobu Matsuno ◽

Naoki Ogawa ◽

Kenji Yasuda ◽

Fumitaka Kagawa ◽

Wataru Koshibae ◽

...

Keyword(s):

Electron Transport ◽

Hall Effect ◽

Solid Angle ◽

Oxide Interface ◽

High Quality ◽

Dm Interaction ◽

Promising Tool ◽

Topological Hall Effect ◽

Magnetic Skyrmions ◽

Epitaxial Oxide

Electron transport coupled with magnetism has attracted attention over the years. Among them, recently discovered is topological Hall effect (THE), originating from scalar spin chirality, that is, the solid angle subtended by the spins. THE is found to be a promising tool for probing the Dzyaloshinskii-Moriya (DM) interaction and consequent magnetic skyrmions. This interaction arises from broken inversion symmetry and hence can be artificially introduced at interface; this concept is lately verified in metal multilayers. However, there are few attempts to investigate such DM interaction at interface through electron transport. We clarified how the transport properties couple with interface DM interaction by fabricating the epitaxial oxide interface. We observed THE in epitaxial bilayers consisting of ferromagnetic SrRuO3 and paramagnetic SrIrO3 over a wide region of both temperature and magnetic field. The magnitude of THE rapidly decreases with the thickness of SrRuO3, suggesting that the interface DM interaction plays a significant role. Such interaction is expected to realize a 10-nm-sized Néel-type magnetic skyrmion. The present results established that the high-quality oxide interface enables us to tune the effective DM interaction; this can be a step toward future topological electronics.

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Topological Hall effect in a system with magnetic skyrmions (Conference Presentation)

Spintronics X ◽

10.1117/12.2277612 ◽

2017 ◽

Author(s):

Igor Rozhansky ◽

Konstantin Denisov ◽

Nikita S. Averkiev ◽

Erkki Lahderanta

Keyword(s):

Hall Effect ◽

Topological Hall Effect ◽

Magnetic Skyrmions

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Toggle-like current-induced Bloch point dynamics of 3D skyrmion strings in a room-temperature nanowire

10.21203/rs.3.rs-1235546/v1 ◽

2022 ◽

Author(s):

Max Birch ◽

David Cortés-Ortuño ◽

Kai Litzius ◽

Sebastian Wintz ◽

Frank Schulz ◽

...

Keyword(s):

Room Temperature ◽

Recent Observation ◽

Three Dimensional ◽

Spatial Dimension ◽

Real Space ◽

Practical Applications ◽

Magnetic Structures ◽

Spintronic Devices ◽

Design Concepts ◽

Magnetic Skyrmions

Abstract Research into practical applications of magnetic skyrmions, nanoscale solitons with interesting topological and transport properties [1,2], has traditionally focused on two dimensional (2D) thin-film systems[3,4]. However, the recent observation of novel three dimensional (3D) skyrmion-like structures, such as hopfions [5], skyrmion strings (SkS) [6-9], skyrmion bundles [11] and skyrmion braids [12], motivates the investigation of new designs, aiming to exploit the third spatial dimension for more compact and higher performance spintronic devices in 3D or curvilinear geometries [13-15]. A crucial requirement of such device schemes is the control of the 3D magnetic structures via charge or spin currents, which has yet to be experimentally observed. In this work, we utilise real-space imaging to investigate the dynamics of a 3D SkS within a nanowire of Co8Zn9Mn3 at room temperature. Utilising single, nanoscale current pulses, we demonstrate current-induced nucleation of a single SkS, and a toggle-like positional switching of an individual Bloch point at the end of a SkS. The observations highlight the possibility to locally manipulate 3D topological spin textures, opening up a range of design concepts for future 3D spintronic devices.

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Visualizing the strongly reshaped skyrmion Hall effect in multilayer wire devices

Nature Communications ◽

10.1038/s41467-021-24114-8 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Anthony K. C. Tan ◽

Pin Ho ◽

James Lourembam ◽

Lisen Huang ◽

Hang Khume Tan ◽

...

Keyword(s):

Hall Effect ◽

Topological Charge ◽

Size Dependence ◽

Particle Model ◽

Model Simulations ◽

Generation Computing ◽

Magnetic Skyrmions ◽

Transverse Deflection ◽

Robust Framework ◽

Geometric Effects

AbstractMagnetic skyrmions are nanoscale spin textures touted as next-generation computing elements. When subjected to lateral currents, skyrmions move at considerable speeds. Their topological charge results in an additional transverse deflection known as the skyrmion Hall effect (SkHE). While promising, their dynamic phenomenology with current, skyrmion size, geometric effects and disorder remain to be established. Here we report on the ensemble dynamics of individual skyrmions forming dense arrays in Pt/Co/MgO wires by examining over 20,000 instances of motion across currents and fields. The skyrmion speed reaches 24 m/s in the plastic flow regime and is surprisingly robust to positional and size variations. Meanwhile, the SkHE saturates at ∼22∘, is substantially reshaped by the wire edge, and crucially increases weakly with skyrmion size. Particle model simulations suggest that the SkHE size dependence — contrary to analytical predictions — arises from the interplay of intrinsic and pinning-driven effects. These results establish a robust framework to harness SkHE and achieve high-throughput skyrmion motion in wire devices.

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