Giant Dzyaloshinskii-Moriya Interaction and Room-Temperature Nanoscale Skyrmions in CoFeB/MgO Heterostructures

2021 ◽  
Author(s):  
Runze Chen ◽  
Xinran Wang ◽  
Houyi Cheng ◽  
Kyu-Joon Lee ◽  
Danrong Xiong ◽  
...  
Keyword(s):  
Room Temperature ◽  
Moriya Interaction

scholarly journals Large Dzyaloshinskii-Moriya interaction induced by chemisorbed oxygen on a ferromagnet surface

2020 ◽  
Vol 6 (33) ◽  
pp. eaba4924 ◽  
Author(s):  
Gong Chen ◽  
Arantzazu Mascaraque ◽  
Hongying Jia ◽  
Bernd Zimmermann ◽  
MacCallum Robertson ◽  
...  
Keyword(s):  
Room Temperature ◽  
Ferromagnetic Layer ◽  
Spin Orbit Coupling ◽  
Winding Number ◽  
Large Magnitude ◽  
Chemisorbed Oxygen ◽  
Magnetic Layers ◽  
Oxygen Coverage ◽  
Opening Up ◽  
Moriya Interaction

The Dzyaloshinskii-Moriya interaction (DMI) is an antisymmetric exchange interaction that stabilizes chiral spin textures. It is induced by inversion symmetry breaking in noncentrosymmetric lattices or at interfaces. Recently, interfacial DMI has been found in magnetic layers adjacent to transition metals due to the spin-orbit coupling and at interfaces with graphene due to the Rashba effect. We report direct observation of strong DMI induced by chemisorption of oxygen on a ferromagnetic layer at room temperature. The sign of this DMI and its unexpectedly large magnitude—despite the low atomic number of oxygen—are derived by examining the oxygen coverage–dependent evolution of magnetic chirality. We find that DMI at the oxygen/ferromagnet interface is comparable to those at ferromagnet/transition metal interfaces; it has enabled direct tailoring of skyrmion’s winding number at room temperature via oxygen chemisorption. This result extends the understanding of the DMI, opening up opportunities for the chemisorption-related design of spin-orbitronic devices.

Multiferroicity in the YFeO3 crystal

2019 ◽  
Vol 13 (01) ◽  
pp. 1950088
Author(s):  
Mingyu Shang ◽  
Haochuan Liu ◽  
Lin Zhang ◽  
Fengyue Sun ◽  
Hongming Yuan ◽  
...  
Keyword(s):  
Rare Earth ◽  
Hydrothermal Method ◽  
Room Temperature ◽  
Magnetic Measurement ◽  
Polarization Measurement ◽  
Antiferromagnetic Ordering ◽  
Saturation Polarization ◽  
Pt Electrodes ◽  
Moriya Interaction ◽  
Antiferromagnetic Behavior

In this paper, orthoferrite YFeO3 was synthesized by hydrothermal method. The space group of YFeO3 is Pnma and the spin state of [Formula: see text] ion is low spin (LS). The YFeO3 crystal exhibits a weak antiferromagnetic behavior by magnetic measurement. For the electrical polarization measurement, micron-scale Pt electrodes were deposited on the both sides of the YFeO3 crystal by FIB-induced deposition. The saturation polarization value is 0.1994[Formula: see text][Formula: see text]C/cm2 at room temperature. The crystal exhibits ferroelectric behavior through the Dzyaloshinskii–Moriya interaction induced by additional spin canting of the antiferromagnetic ordering. This work may be applied to further study of the multiferroicity in rare-earth orthoferrites RFeO3.

scholarly journals Spin-wave spectroscopy of the Dzyaloshinskii-Moriya interaction in room-temperature chiral magnets hosting skyrmions

2017 ◽  
Vol 95 (22) ◽  
Author(s):  
R. Takagi ◽  
D. Morikawa ◽  
K. Karube ◽  
N. Kanazawa ◽  
K. Shibata ◽  
...  
Keyword(s):  
Spin Wave ◽  
Room Temperature ◽  
Moriya Interaction

scholarly journals Robust skyrmion mediated reversal of ferromagnetic nanodots of 20 nm lateral dimension with high Ms and observable DMI

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Md Mahadi Rajib ◽  
Walid Al Misba ◽  
Dhritiman Bhattacharya ◽  
Jayasimha Atulasimha
Keyword(s):  
Saturation Magnetization ◽  
Data Storage ◽  
Energy Efficient ◽  
Room Temperature ◽  
Thermal Noise ◽  
Stray Field ◽  
Lateral Dimension ◽  
Storage Devices ◽  
20 Nm ◽  
Moriya Interaction

AbstractImplementation of skyrmion based energy efficient and high-density data storage devices requires aggressive scaling of skyrmion size. Ferrimagnetic materials are considered to be a suitable platform for this purpose due to their low saturation magnetization (i.e. smaller stray field). However, this method of lowering the saturation magnetization and scaling the lateral size of skyrmions is only applicable where the skyrmions have a smaller lateral dimension compared to the hosting film. Here, we show by performing rigorous micromagnetic simulation that the size of skyrmions, which have lateral dimension comparable to their hosting nanodot can be scaled by increasing saturation magnetization. Also, when the lateral dimension of nanodot is reduced and thereby the skyrmion confined in it is downscaled, there remains a challenge in forming a stable skyrmion with experimentally observed Dzyaloshinskii–Moriya interaction (DMI) values since this interaction has to facilitate higher canting  per spin to complete a 360° rotation along the diameter. In our study, we found that skyrmions can be formed in 20 nm lateral dimension nanodots with high saturation magnetization (1.30–1.70 MA/m) and DMI values (~ 3 mJ/m2) that have been reported to date. This result could stimulate experiments on implementation of highly dense skyrmion devices. Additionally, using this, we show that voltage controlled magnetic anisotropy based switching mediated by an intermediate skyrmion state can be achieved in the soft layer of a ferromagnetic p-MTJ of lateral dimensions 20 nm with sub 1 fJ/bit energy in the presence of room temperature thermal noise with reasonable DMI ~ 3 mJ/m2.

scholarly journals Formation and current-induced motion of synthetic antiferromagnetic skyrmion bubbles

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Takaaki Dohi ◽  
Samik DuttaGupta ◽  
Shunsuke Fukami ◽  
Hideo Ohno
Keyword(s):  
Hall Effect ◽  
Current Density ◽  
Energy Efficient ◽  
Topological Charge ◽  
Room Temperature ◽  
Threshold Current ◽  
Threshold Current Density ◽  
New Directions ◽  
Induced Motion ◽  
Moriya Interaction

AbstractSkyrmion, a topologically-protected soliton, is known to emerge via electron spin in various magnetic materials. The magnetic skyrmion can be driven by low current density and has a potential to be stabilized in nanoscale, offering new directions of spintronics. However, there remain some fundamental issues in widely-studied ferromagnetic systems, which include a difficulty to realize stable ultrasmall skyrmions at room temperature, presence of the skyrmion Hall effect, and limitation of velocity owing to the topological charge. Here we show skyrmion bubbles in a synthetic antiferromagnetic coupled multilayer that are free from the above issues. Additive Dzyaloshinskii-Moriya interaction and spin-orbit torque (SOT) of the tailored stack allow stable skyrmion bubbles at room temperature, significantly smaller threshold current density or higher speed for motion, and negligible skyrmion Hall effect, with a potential to be scaled down to nanometer dimensions. The results offer a promising pathway toward nanoscale and energy-efficient skyrmion-based devices.

scholarly journals Investigation of the Dzyaloshinskii-Moriya interaction and room temperature skyrmions in W/CoFeB/MgO thin films and microwires

2017 ◽  
Vol 111 (2) ◽  
pp. 022409 ◽  
Author(s):  
S. Jaiswal ◽  
K. Litzius ◽  
I. Lemesh ◽  
F. Büttner ◽  
S. Finizio ◽  
...  
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Moriya Interaction

Strain-Driven Dzyaloshinskii-Moriya Interaction for Room-Temperature Magnetic Skyrmions

2021 ◽  
Vol 127 (11) ◽  
Author(s):  
Yuelin Zhang ◽  
Jie Liu ◽  
Yongqi Dong ◽  
Shizhe Wu ◽  
Jianyu Zhang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Magnetic Skyrmions ◽  
Moriya Interaction

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.

scholarly journals Large Dzyaloshinskii-Moriya interaction and room-temperature nanoscale skyrmions in CoFeB/MgO heterostructures

2021 ◽  
pp. 100618
Author(s):  
Runze Chen ◽  
Xinran Wang ◽  
Houyi Cheng ◽  
Kyu-Joon Lee ◽  
Danrong Xiong ◽  
...  
Keyword(s):  
Room Temperature ◽  
Moriya Interaction

Dependence of Intergranular Fracture on Boundary Topography and Cohesion

1973 ◽  
Vol 31 ◽  
pp. 150-151
Author(s):  
J. E. Doherty ◽  
A. F. Giamei ◽  
B. H. Kear ◽  
C. W. Steinke
Keyword(s):  
Grain Boundary ◽  
Room Temperature ◽  
Nickel Base Superalloy ◽  
Boundary Shear ◽  
Room Temperature Ductility ◽  
Solid Solution Matrix ◽  
Nickel Base ◽  
Solution Matrix ◽  
Different Levels ◽  
Base Superalloy

Recently we have been investigating a class of nickel-base superalloys which possess substantial room temperature ductility. This improvement in ductility is directly related to improvements in grain boundary strength due to increased boundary cohesion through control of detrimental impurities and improved boundary shear strength by controlled grain boundary micros true tures.For these investigations an experimental nickel-base superalloy was doped with different levels of sulphur impurity. The micros tructure after a heat treatment of 1360°C for 2 hr, 1200°C for 16 hr consists of coherent precipitates of γ’ Ni3(Al,X) in a nickel solid solution matrix.

Sign in / Sign up

Export Citation Format

Share Document