scholarly journals Universal method for magnetic skyrmion bubble generation by controlling the stripe domain instability

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Kyoung-Woong Moon ◽  
Seungmo Yang ◽  
Tae-Seong Ju ◽  
Changsoo Kim ◽  
Byoung Sun Chun ◽  
...  
Keyword(s):  
Perpendicular Magnetic Anisotropy ◽  
Magnetic Films ◽  
Universal Method ◽  
Stripe Domain ◽  
Bubble Generation ◽  
Spintronic Devices ◽  
Material Parameters ◽  
Magnetic Skyrmions ◽  
General Method ◽  
Key Parameter

AbstractMagnetic skyrmions, which are topological swirling spin textures, have drawn much attention in spintronics because of their use as an information carrier with distinct robustness rooted in their topological nature. Real-time generation of skyrmions is therefore imperative for realizing skyrmion-based spintronic devices. However, to date, experimental demonstration has been limited to exquisite works with well-tuned samples. Here, we report a method to generate skyrmions by driving the stripe instability via an in-plane magnetic field. We have demonstrated that the key parameter determining the stripe domain instability is the stripe width, regardless of other material parameters. This skyrmion generation method can be applicable to generic magnetic films with perpendicular magnetic anisotropy. Our work will facilitate the development of skyrmion-based devices by offering a general method for controlling a large skyrmion population.

Thermal-Driven Evolution of Magnetic Domain Structures in Ultrathin Films

2006 ◽  
Vol 112 ◽  
pp. 101-108 ◽  
Author(s):  
V. Zablotskii ◽  
Andrzej Maziewski ◽  
T. Polyakova
Keyword(s):  
Ultrathin Films ◽  
Characteristic Length ◽  
Magnetic Domain ◽  
Magnetic Films ◽  
Spin Reorientation ◽  
Stripe Domain ◽  
Domain Structures ◽  
Increasing Temperature ◽  
Domain Period ◽  
Key Parameter

The thermal-driven evolution of stripe domain structures in ultrathin magnetic films is analyzed with regard to temperature dependencies of the film magnetic parameters. In the vicinity of the Curie temperature or points of the spin reorientation the equilibrium stripe domain period was found to exponentially decrease with increasing temperature. It is shown that the temperature dependence of the characteristic length is the key parameter controlling the domain period changes. Irreversible and reversible changes of the domain period as well as the so-called inverse domain melting are discussed.

scholarly journals Manipulation of Skyrmion Motion Dynamics for Logical Device Application Mediated by Inhomogeneous Magnetic Anisotropy

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 278
Author(s):  
Jia-Qiang Lin ◽  
Ji-Pei Chen ◽  
Zhen-Yu Tan ◽  
Yuan Chen ◽  
Zhi-Feng Chen ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
High Mobility ◽  
Perpendicular Magnetic Anisotropy ◽  
Micromagnetic Simulation ◽  
Spintronic Devices ◽  
Potential Barriers ◽  
Device Application ◽  
Size And Shape ◽  
Magnetic Skyrmions ◽  
Motion Dynamics

Magnetic skyrmions are promising potential information carriers for future spintronic devices owing to their nanoscale size, non-volatility and high mobility. In this work, we demonstrate the controlled manipulation of skyrmion motion and its implementation in a new concept of racetrack logical device by introducing an inhomogeneous perpendicular magnetic anisotropy (PMA) via micromagnetic simulation. Here, the inhomogeneous PMA can be introduced by a capping nano-island that serves as a tunable potential barriers/well which can effectively modulate the size and shape of isolated skyrmion. Using the inhomogeneous PMA in skyrmion-based racetrack enables the manipulation of skyrmion motion behaviors, for instance, blocking, trapping or allowing passing the injected skyrmion. In addition, the skyrmion trapping operation can be further exploited in developing special designed racetrack devices with logic AND and NOT, wherein a set of logic AND operations can be realized via skyrmion–skyrmion repulsion between two skyrmions. These results indicate an effective method for tailoring the skyrmion structures and motion behaviors by using inhomogeneous PMA, which further provide a new pathway to all-electric skyrmion-based memory and logic devices.

A Theory of Skyrmion Size in Skyrmion Crystals

2021 ◽  
Author(s):  
X. R. Wang ◽  
H. T. Wu ◽  
X. C. Hu ◽  
K. Y. Jing
Keyword(s):  
Magnetic Anisotropy ◽  
Room Temperature ◽  
Perpendicular Magnetic Anisotropy ◽  
Magnetic Films ◽  
Ferromagnetic Phase ◽  
Square Root ◽  
Number Density ◽  
Material Parameters ◽  
Stiffness Constant ◽  
Moriya Interaction

Abstract A magnetic skyrmion is a topological object that can exist as a solitary embedded in the vast ferromagnetic phase, or coexists with a group of its "siblings" in various stripy phases as well as skyrmion crystals (SkXs). Isolated skyrmions and skyrmions in an SkX are circular while a skyrmion in other phases is a stripe of various forms. Unexpectedly, the sizes of the three different class of skyrmions depend on material parameters differently. For chiral magnetic films with exchange stiffness constant A, the Dzyaloshinskii-Moriya interaction (DMI) strength D, and perpendicular magnetic anisotropy K, κ=π2D2⁄(16AK)=1 separates isolated skyrmions from condensed skyrmion states. In contrast to isolated skyrmions whose size increases with D⁄K and is insensitive to κ<<1 and stripe skyrmions whose width increases with A⁄D and is insensitive to κ>>1, the size of skyrmions in SkXs is inversely proportional to the square root of skyrmion number density and decreases with A⁄D. This finding has important implications in searching for stable smaller skyrmions at the room temperature.

CORRELATIONS BETWEEN STRUCTURE AND MAGNETISM IN THIN FILMS AND NANOSTRUCTURES

1999 ◽  
Vol 06 (05) ◽  
pp. 753-761 ◽  
Author(s):  
P. LE FÈVRE ◽  
H. MAGNAN ◽  
A. MIDOIR ◽  
D. CHANDESRIS ◽  
H. JAFFRÈS ◽  
...  
Keyword(s):  
Thin Films ◽  
Structural Characterization ◽  
Structural Relaxation ◽  
Easy Axis ◽  
Perpendicular Magnetic Anisotropy ◽  
Magnetic Films ◽  
Bulk Solids ◽  
Thin Magnetic Films ◽  
Distorted Structure ◽  
Crystallographic Structures

The bidimensionnal character of thin magnetic films deposited on single-crystal substrates, together with the occurrence of singular crystallographic structures, often confer on these systems electronic properties that cannot be found in bulk solids. For example, thin Ni layers deposited on Cu(001) present a perpendicular magnetic anisotropy in a very wide thickness range. We will show that this can be explained by a distorted structure of Ni, originating from the strain induced by the epitaxy on the Cu substrate. In this field of 2D magnetism, nanostructures are now investigated. Thin Fe layers on MgO(001) were cut into stripes by the "atomic saw" method: a compression of the substrate induces a dislocation slipping which saws both the substrate and the Fe film in regular and separated ribbons. The observed perpendicular to the stripes magnetization easy axis will be explained by a structural relaxation occurring during the structuration process. In these two studies, a precise structural characterization and simple magnetoelastic models allow one to describe the magnetic behaviors of these systems.

scholarly journals Dynamics and stability of skyrmions in a bended nano-beam

2021 ◽  
Author(s):  
Anruo Zhong ◽  
Xiaoming Lan ◽  
Yangfan Hu ◽  
Biao Wang
Keyword(s):  
Energy Cost ◽  
High Mobility ◽  
Bending Moment ◽  
Elastic Fields ◽  
Spintronic Devices ◽  
Bulk Stress ◽  
The Stability ◽  
Magnetic Skyrmions ◽  
Nontrivial Topology ◽  
A Current

Abstract Magnetic skyrmions are attracting much attention due to their nontrivial topology and high mobility to electric current. Nevertheless, suppression of the skyrmion Hall effect and maintaining high velocity of skyrmions with low energy cost are two major challenges concerning skyrmion-based spintronic devices. Here we show theoretically that in a nano-beam suffering appropriate bending moment, both Bloch-type and Néel-type skyrmions move with a vanishing Hall angle under a current density smaller than that required when the bending is absent. Moreover, bending alone can be used to move skyrmions, whose velocity is solved analytically from the Thiele equation. Generally speaking, inhomogeneous elastic fields affect the stability and dynamics of skyrmions, where the local stability is dominantly determined by the local bulk stress. These findings throw new light on how to drive skyrmions straightly with lower energy cost, which is vital for utilizing skyrmions as information carriers.

VOLTAGE-CONTROLLED MAGNETIC ANISOTROPY IN SPINTRONIC DEVICES

SPIN ◽  
2012 ◽  
Vol 02 (03) ◽  
pp. 1240002 ◽  
Author(s):  
PEDRAM KHALILI AMIRI ◽  
KANG L. WANG
Keyword(s):  
Magnetic Anisotropy ◽  
Random Access ◽  
Magnetic Tunnel Junction ◽  
Magnetic Films ◽  
Magnetization Dynamics ◽  
Spintronic Devices ◽  
Magnetic Random Access Memory ◽  
Thin Magnetic Films ◽  
Potential Applications ◽  
New Generation

Electric-field-control of magnetism can dramatically improve the energy efficiency of spintronic devices and enhance the performance of magnetic memories. More generally, it expands the range of applications of nonvolatile spintronic devices, by making them energetically competitive compared to conventional semiconductor solutions for logic and computation, thereby potentially enabling a new generation of ultralow-power nonvolatile spintronic systems. This paper reviews recent experiments on the voltage-controlled magnetic anisotropy (VCMA) effect in thin magnetic films, and their device implications. The interfacial perpendicular anisotropy in layered magnetic material stacks, as well as its modulation by voltage, are discussed. Ferromagnetic resonance experiments and VCMA-induced high-frequency magnetization dynamics are reviewed. Finally, we discuss recent progress on voltage-induced switching of magnetic tunnel junction devices and its potential applications to magnetic random access memory (MRAM).

Perpendicular Magnetic Anisotropy in Fe–N Thin Films: Threshold Field for Irreversible Magnetic Stripe Domain Rotation

SPIN ◽  
2016 ◽  
Vol 06 (04) ◽  
pp. 1640014 ◽  
Author(s):  
L.-C. Garnier ◽  
M. Eddrief ◽  
S. Fin ◽  
D. Bisero ◽  
F. Fortuna ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Magnetic Anisotropy ◽  
Magnetic Measurements ◽  
Perpendicular Magnetic Anisotropy ◽  
The Body ◽  
Threshold Field ◽  
Iron Nitride ◽  
Magnetic Field Direction ◽  
Stripe Domain

The magnetic properties of an iron nitride thin film obtained by ion implantation have been investigated. N[Formula: see text] ions were implanted in a pristine iron layer epitaxially grown on ZnSe/GaAs(001). X-ray diffraction measurements revealed the formation of body-centered tetragonal N-martensite whose [Formula: see text]-axis is perpendicular to the thin film plane and [Formula: see text]-parameter is close to that of [Formula: see text]-Fe8N. Magnetic measurements disclosed a weak perpendicular magnetic anisotropy (PMA) whose energy density [Formula: see text] was assessed to about 105[Formula: see text]J/m3. A sharp decline of the in-plane magnetocrystalline anisotropy (MCA) was also observed, in comparison with the body-centered cubic iron. The origin of the PMA is attributed to the MCA of N-martensite and/or stress-induced anisotropy. As a result of the PMA, weak magnetic stripe domains with a period of about 130[Formula: see text]nm aligned along the last saturating magnetic field direction were observed at remanence by magnetic force microscopy. The application of an increasing in-plane magnetic field transverse to the stripes [Formula: see text] highlighted a threshold value ([Formula: see text][Formula: see text]T) above which these magnetic domains irreversibly rotated. Interestingly, below this threshold, the stripes do not rotate, leading to a zero remanent magnetization along the direction of the applied field. The interest of this system for magnetization dynamics is discussed.

scholarly journals Magnetic Skyrmion Generation by Reflective Spin Wave Focusing

2021 ◽  
Vol 9 ◽  
Author(s):  
Xianglong Yao ◽  
Zhenyu Wang ◽  
Menghua Deng ◽  
Z.-X. Li ◽  
Zhizhi Zhang ◽  
...  
Keyword(s):  
Topological Charge ◽  
Path Length ◽  
Focal Point ◽  
Spin Waves ◽  
Micromagnetic Simulations ◽  
Driving Field ◽  
Spintronic Devices ◽  
Theoretical Design ◽  
Frequency Independent ◽  
Magnetic Skyrmions

We propose a method to generate magnetic skyrmions by focusing spin waves totally reflected by a curved film edge. The edge contour is derived to be parabolic and frequency-independent based on the identical magnonic path length principle. We performed micromagnetic simulations to verify our theoretical design. Under proper conditions, the reflected spin waves first converge at the focal point with the enhanced intensity leading to the emergence of magnetic droplets, which are then converted to magnetic skyrmion accompanied by a change in the topological charge. We numerically obtain the phase diagram of skyrmion generation with respect to the amplitude and frequency of the driving field. Our finding would be helpful for the design of spintronic devices combining the advantage of skyrmionics and magnonics.

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