scholarly journals Magnetic switching of nanoscale antidot lattices

2016 ◽  
Vol 7 ◽  
pp. 733-750 ◽  
Author(s):  
Ulf Wiedwald ◽  
Joachim Gräfe ◽  
Kristof M Lebecki ◽  
Maxim Skripnik ◽  
Felix Haering ◽  
...  
Keyword(s):  
Nanosphere Lithography ◽  
Magnetic Film ◽  
Micromagnetic Simulations ◽  
First Order ◽  
Magnetic Switching ◽  
Out Of Plane ◽  
Magnetic Microscopy ◽  
The Rich ◽  
Microscopy Techniques

We investigate the rich magnetic switching properties of nanoscale antidot lattices in the 200 nm regime. In-plane magnetized Fe, Co, and Permalloy (Py) as well as out-of-plane magnetized GdFe antidot films are prepared by a modified nanosphere lithography allowing for non-close packed voids in a magnetic film. We present a magnetometry protocol based on magneto-optical Kerr microscopy elucidating the switching modes using first-order reversal curves. The combination of various magnetometry and magnetic microscopy techniques as well as micromagnetic simulations delivers a thorough understanding of the switching modes. While part of the investigations has been published before, we summarize these results and add significant new insights in the magnetism of exchange-coupled antidot lattices.

Out-of-plane static compression and energy absorption of paper hierarchical corrugation sandwich panels

2021 ◽  
pp. 030932472110085
Author(s):  
Huineng Wang ◽  
Yanfeng Guo ◽  
Yungang Fu ◽  
Dan Li
Keyword(s):  
Yield Strength ◽  
Bearing Capacity ◽  
Energy Absorption ◽  
Sandwich Panel ◽  
Second Order ◽  
Compression Rate ◽  
Static Compression ◽  
First Order ◽  
Out Of Plane ◽  
Analytical Approaches

This study introduces the opinion of the corrugation hierarchy to develop the second-order corrugation paperboard, and explore the deformation characteristics, yield strength, and energy absorbing capacity under out-of-plane static evenly compression loading by experimental and analytical approaches. On the basis of the inclined-straight strut elements of corrugation unit and plastic hinge lines, the yield and crushing strengths of corrugation unit were analyzed. This study shows that as the compressive stress increases, the second-order corrugation core layer is firstly crushed, and the first-order corrugation structures gradually compacted until the failure of entire structure. The corrugation type has an obvious influence on the yield strength of the corrugation sandwich panel, and the yield strength of B-flute corrugation sandwich panel is wholly higher than that of the C-flute structure. At the same compression rate, the flute type has a significant impact on energy absorption, and the C-flute second-order corrugation sandwich panel has better bearing capacity than the B-flute structure. The second-order corrugation sandwich panel has a better bearing capacity than the first-order structure. The static compression rate has little effect on the yield strength and deformation mode. However, with the increase of the static compression rate, the corrugation sandwich panel has a better cushioning energy absorption and material utilization rate.

scholarly journals Prediction of the Progressive Loss of Winding Clamping Pressure in Power Transformers

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Shuguo Gao ◽  
Jun Zhao ◽  
Lingming Meng ◽  
Hongliang Liu
Keyword(s):  
Mechanical Properties ◽  
Initial Pressure ◽  
Order Reaction ◽  
Power Transformers ◽  
Pressure Drops ◽  
First Order ◽  
Progressive Loss ◽  
Out Of Plane ◽  
Transformer Winding ◽  
Clamping Pressure

This paper investigates the progressive loss of winding clamping pressure resulted from thermal aging in power transformers. Firstly, out-of-plane stress-strain characteristics of aging pressboards are investigated experimentally and relationship between mechanical properties of pressboards and aging hours is established accordingly. Then, a thermal-mechanical model is built to correlate the aging time with temperature based on the first-order reaction kinetics. Based on the above investigations, the correlation between temperature and mechanical properties of pressboards is obtained and the progressive loss of clamping pressure is predicted. The results show that with the progressive softening of pressboards from aging, the clamping pressure drops linearly under 60°C and nonlinearly over 60°C. The remaining clamping pressure of a transformer winding with 30 years’ service history is only 80.12% and 51.59% of its initial pressure under 50°C and 60°C, respectively.

Refined First-Order Shear Deformation Theory Models for Composite Laminates

2003 ◽  
Vol 70 (3) ◽  
pp. 381-390 ◽  
Author(s):  
F. Auricchio ◽  
E. Sacco
Keyword(s):  
Shear Deformation ◽  
Analytical Solutions ◽  
Composite Laminates ◽  
Three Dimensional ◽  
Shear Deformation Theory ◽  
Quadratic Functions ◽  
Shear Stresses ◽  
Stress Profile ◽  
First Order ◽  
Out Of Plane

In the present work, new mixed variational formulations for a first-order shear deformation laminate theory are proposed. The out-of-plane stresses are considered as primary variables of the problem. In particular, the shear stress profile is represented either by independent piecewise quadratic functions in the thickness or by satisfying the three-dimensional equilibrium equations written in terms of midplane strains and curvatures. The developed formulations are characterized by several advantages: They do not require the use of shear correction factors as well as the out-of-plane shear stresses can be derived without post-processing procedures. Some numerical applications are presented in order to verify the effectiveness of the proposed formulations. In particular, analytical solutions obtained using the developed models are compared with the exact three-dimensional solution, with other classical laminate analytical solutions and with finite element results. Finally, we note that the proposed formulations may represent a rational base for the development of effective finite elements for composite laminates.

Dynamics of Dzyaloshinskii Domain Walls Driven by Spin Hall Effect in the Presence of Magnetic Fields

SPIN ◽  
2017 ◽  
Vol 07 (01) ◽  
pp. 1740004
Author(s):  
Chengkun Song ◽  
Chendong Jin ◽  
Jianbo Wang ◽  
Qingfang Liu
Keyword(s):  
Magnetic Fields ◽  
Hall Effect ◽  
Domain Walls ◽  
Domain Wall Motion ◽  
Spin Hall Effect ◽  
Micromagnetic Simulations ◽  
Out Of Plane ◽  
Device Applications ◽  
Metal Bilayers ◽  
The Magnetic Field

Current-induced domain wall motion (CIDWM) in perpendicularly magnetized materials exhibits large potential in spintronic device applications. The Dzyaloshinskii domain walls (DWs) are nucleated in ultrathin ferromagnetic/heavy-metal bilayers with high perpendicular magnetocrystalline anisotropy (PMA) in the presence of interfacial Dzyaloshinskii–Moriya interaction (DMI). Here, we investigate the effect of magnetic fields on Dzyaloshinskii DWs driven by spin Hall effect (SHE) by means of micromagnetic simulations. We find that magnetic fields can modify the dynamics of Dzyaloshinskii DW. When applying out-of-plane magnetic fields, the velocity of Dzyaloshinskii DWs increases when the field-driven and current-driven DW motion are in same direction, while it decreases with opposite direction. In the case of in-plane longitudinal magnetic fields, Dzyaloshinskii DW velocity increases when the direction of the magnetic field and Dzyaloshinskii DW propagation direction are same, and it decreases when applying opposite in-plane magnetic fields. These manifestations may offer a new method for manipulating Dzyaloshinskii DWs and promise applications in DW-based nanodevices.

scholarly journals Multiscale computational first order homogenization of thick shells for the analysis of out-of-plane loaded masonry walls

2017 ◽  
Vol 315 ◽  
pp. 273-301 ◽  
Author(s):  
Massimo Petracca ◽  
Luca Pelà ◽  
Riccardo Rossi ◽  
Sergio Oller ◽  
Guido Camata ◽  
...  
Keyword(s):  
Masonry Walls ◽  
First Order ◽  
Out Of Plane ◽  
Thick Shells

scholarly journals Robust separation of topological in-plane and out-of-plane waves in a phononic crystal

2022 ◽  
Vol 5 (1) ◽  
Author(s):  
Myung-Joon Lee ◽  
Il-Kwon Oh
Keyword(s):  
Elastic Wave ◽  
Phononic Crystal ◽  
Plane Waves ◽  
Degree Of Freedom ◽  
Wave Separation ◽  
Simultaneous Control ◽  
Accidental Degeneracy ◽  
Out Of Plane ◽  
Wave Path ◽  
The Rich

AbstractValley degree of freedom, associated with the valley topological phase, has propelled the advancement of the elastic waveguide by offering immunity to backscattering against bending and weak perturbations. Despite many attempts to manipulate the wave path and working frequency of the waveguide, internal characteristic of an elastic wave such as rich polarization has not yet been utilized with valley topological phases. Here, we introduce the rich polarization into the valley degree of freedom, to achieve topologically protected in-plane and out-of-plane mode separation of an elastic wave. Accidental degeneracy proves its real worth of decoupling the in-plane and out-of-plane polarized valley Hall phases. We further demonstrate independent and simultaneous control of in-plane and out-of-plane waves, with intact topological protection. The presenting procedure for designing the topologically protected wave separation based on accidental degeneracy will widen the valley topological physics in view of both generation mechanism and application areas.

scholarly journals Tunable layered-magnetism–assisted magneto-Raman effect in a two-dimensional magnet CrI3

2020 ◽  
Vol 117 (40) ◽  
pp. 24664-24669
Author(s):  
Wencan Jin ◽  
Zhipeng Ye ◽  
Xiangpeng Luo ◽  
Bowen Yang ◽  
Gaihua Ye ◽  
...  
Keyword(s):  
Phonon Scattering ◽  
Raman Effect ◽  
Higher Order ◽  
Magnetic Phase Transitions ◽  
Two Dimensional ◽  
Phonon Coupling ◽  
Scattering Mechanism ◽  
First Order ◽  
Critical Magnetic Fields ◽  
The Rich

We used a combination of polarized Raman spectroscopy experiment and model magnetism–phonon coupling calculations to study the rich magneto-Raman effect in the two-dimensional (2D) magnet CrI3. We reveal a layered-magnetism–assisted phonon scattering mechanism below the magnetic onset temperature, whose Raman excitation breaks time-reversal symmetry, has an antisymmetric Raman tensor, and follows the magnetic phase transitions across critical magnetic fields, on top of the presence of the conventional phonon scattering with symmetric Raman tensors in N-layer CrI3. We resolve in data and by calculations that the first-order Ag phonon of the monolayer splits into an N-fold multiplet in N-layer CrI3 due to the interlayer coupling (N≥2) and that the phonons within the multiplet show distinct magnetic field dependence because of their different layered-magnetism–phonon coupling. We further find that such a layered-magnetism–phonon coupled Raman scattering mechanism extends beyond first-order to higher-order multiphonon scattering processes. Our results on the magneto-Raman effect of the first-order phonons in the multiplet and the higher-order multiphonons in N-layer CrI3 demonstrate the rich and strong behavior of emergent magneto-optical effects in 2D magnets and underline the unique opportunities of spin–phonon physics in van der Waals layered magnets.

A Study of the Deformation Measurement of 3D Displacement Field

2005 ◽  
Vol 295-296 ◽  
pp. 313-318
Author(s):  
S.R. Lee ◽  
Z.S. Luo ◽  
H.S. Chiou ◽  
B.G. Wang ◽  
L.S. Liu
Keyword(s):  
Displacement Field ◽  
Incident Angle ◽  
Vertical Direction ◽  
Moiré Interferometry ◽  
Deformation Measurement ◽  
Measuring Error ◽  
Moire Interferometry ◽  
First Order ◽  
Out Of Plane ◽  
Plane Displacement

With the development of modern engineering such as micro-electro-mechanical system (MEMS) and new material, the deformation measurement of 3D displacement field is required. Moiré interferometry has become common for measuring the deformations of two-dimension in-plane displacement field. To solve the problem of 3D displacement field, a system for measuring the deformations of 3D displacement field is designed. By using this system, we can measure the out-of-plane displacement by appending a set of electronic speckle interference system based on Moiré interferometry system. Adjusting the incident angle of the incident light, the transmitting direction of the first order diffracted wave in a Moiré interferometry system is assigned to deviate with a small angle from the vertical direction of the specimen surface. Thus the first order diffracted wave is separated from the place of the appended interference field. The striated patterns of the deformations of 3D displacement field can be obtained at the same time. These striated patterns are recorded respectively by three CCD cameras and are stored and processed by a computer. The synchronous measuring method brings certain amount of measuring errors into the measurement of in-plane displacement. This measuring error is analyzed in theory. When real-time measurement is not required, this system can be changed into another system in which the in-plane and the out-of-plane displacement field are measured by time sharing to reduce the measuring errors. The theoretical derivation and a part of experimental results for verification are presented.

scholarly journals Competing correlated states and abundant orbital magnetism in twisted monolayer-bilayer graphene

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Minhao He ◽  
Ya-Hui Zhang ◽  
Yuhao Li ◽  
Zaiyao Fei ◽  
Kenji Watanabe ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Anomalous Hall Effect ◽  
Bilayer Graphene ◽  
Flat Band ◽  
Zero Field ◽  
First Order ◽  
Orbital Magnetism ◽  
Valley Polarization ◽  
The Rich ◽  
Topological Phase Transitions

AbstractFlat band moiré superlattices have recently emerged as unique platforms for investigating the interplay between strong electronic correlations, nontrivial band topology, and multiple isospin ‘flavor’ symmetries. Twisted monolayer-bilayer graphene (tMBG) is an especially rich system owing to its low crystal symmetry and the tunability of its bandwidth and topology with an external electric field. Here, we find that orbital magnetism is abundant within the correlated phase diagram of tMBG, giving rise to the anomalous Hall effect in correlated metallic states nearby most odd integer fillings of the flat conduction band, as well as correlated Chern insulator states stabilized in an external magnetic field. The behavior of the states at zero field appears to be inconsistent with simple spin and valley polarization for the specific range of twist angles we investigate, and instead may plausibly result from an intervalley coherent (IVC) state with an order parameter that breaks time reversal symmetry. The application of a magnetic field further tunes the competition between correlated states, in some cases driving first-order topological phase transitions. Our results underscore the rich interplay between closely competing correlated ground states in tMBG, with possible implications for probing exotic IVC ordering.

scholarly journals Reasoning Inside The Box: Deduction in Herbrand Logics

10.29007/kx2m ◽  
2018 ◽  
Author(s):  
Liron Cohen ◽  
Yoni Zohar
Keyword(s):  
Automated Reasoning ◽  
Proof System ◽  
First Order ◽  
Proof Systems ◽  
The Rich ◽  
Order Structures ◽  
Effective Proof

Herbrand structures are a subclass of standard first-order structures commonly used in logic and automated reasoning due to their strong definitional character. This paper is devoted to the logics induced by them: Herbrand and semi-Herbrand logics, with and without equality. The rich expressiveness of these logics entails that there is no adequate effective proof system for them. We therefore introduce infinitary proof systems for Herbrand logics, and prove their completeness. Natural and sound finitary approximations of the infinitary systems are also presented.

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