On Convergence of the Cavity and Bolthausen’s TAP Iterations to the Local Magnetization

t is shown that the inverse Faraday effect appears in the case of surface plasmon polariton propagation near a metal-paramagnetic interface. The inverse Faraday effect in nanostructured periodically perforated metaldielectric films increases because of the excitation of surface plasmon polaritons. In this case, a stationary magnetic field is amplified by more than an order of magnitude compared to the case of a smooth paramagnetic film. The distribution of an electromagnetic field is sensitive to the wavelength and the angle of incidence of light, which allows one to efficiently control the local magnetization arising due to the inverse Faraday effect.

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Iron loss simulation using a local material model

COMPEL The International Journal for Computation and Mathematics in Electrical and Electronic Engineering ◽

10.1108/compel-10-2018-0421 ◽

2019 ◽

Vol 38 (4) ◽

pp. 1224-1234

Author(s):

Benedikt Groschup ◽

Silas Elfgen ◽

Kay Hameyer

Keyword(s):

A Priori ◽

Material Model ◽

Edge Length ◽

Iron Loss ◽

Local Magnetization ◽

Content Type ◽

Local Loss ◽

Cut Edge ◽

Iron Losses ◽

Local Material

Purpose The cutting process of the electric machine laminations causes residual mechanical stress in the soft magnetic material. A local magnetic deterioration can be observed and the resulting local and global iron losses increase. A continuous local material model for the consideration of the changing magnetization properties has been introduced in a previous work as well as an a priori assessment of iron losses. A local iron loss calculation considering both a local magnetization and local loss parameters misses yet. The purpose of this study is to introduce a local iron loss calculation model considering both a local magnetization and local loss parameters. Design/methodology/approach In this paper, an approach for local iron loss simulation is developed and a comparison to the cut-edge length-dependent loss model is given. The comparison includes local loss distribution in the lamination as well as the impact on the overall motor efficiency and vehicle range in an electric vehicle driving cycle. Findings For an analysis of the resulting local iron loss components, both the local magnetization and iron loss parameters must be considered using physically based models. Consistently, a local iron loss model is presented in the work. The developed model can be used to gain detailed information of the local loss distribution inside the machine. The comparability of this local iron loss with the cut-edge length approach for overall system characteristics, e.g. efficiency or driving range, is shown. Originality/value A local iron loss simulation approach is a physical accurate model to describe the influence of cutting techniques on electric machine characteristics. A comparison with the less complicated a priori assessment gives detailed information about the necessity of the local model under consideration of the given problem.

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Magnetization switching by magnon-mediated spin torque through an antiferromagnetic insulator

Science ◽

10.1126/science.aav8076 ◽

2019 ◽

Vol 366 (6469) ◽

pp. 1125-1128 ◽

Cited By ~ 27

Author(s):

Yi Wang ◽

Dapeng Zhu ◽

Yumeng Yang ◽

Kyusup Lee ◽

Rahul Mishra ◽

...

Keyword(s):

Spin Transfer Torque ◽

Spin Transfer ◽

Spin Torque ◽

Local Magnetization ◽

Magnetization Switching ◽

Spintronic Devices ◽

Magnetic Devices ◽

Alternative Approach ◽

Efficient Control ◽

Electrical Spin

Widespread applications of magnetic devices require an efficient means to manipulate the local magnetization. One mechanism is the electrical spin-transfer torque associated with electron-mediated spin currents; however, this suffers from substantial energy dissipation caused by Joule heating. We experimentally demonstrated an alternative approach based on magnon currents and achieved magnon-torque–induced magnetization switching in Bi2Se3/antiferromagnetic insulator NiO/ferromagnet devices at room temperature. The magnon currents carry spin angular momentum efficiently without involving moving electrons through a 25-nanometer-thick NiO layer. The magnon torque is sufficient to control the magnetization, which is comparable with previously observed electrical spin torque ratios. This research, which is relevant to the energy-efficient control of spintronic devices, will invigorate magnon-based memory and logic devices.

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Magnetic field transport in compact binaries

Astronomy and Astrophysics ◽

10.1051/0004-6361/202037903 ◽

2020 ◽

Vol 641 ◽

pp. A133

Author(s):

N. Scepi ◽

G. Lesur ◽

G. Dubus ◽

J. Jacquemin-Ide

Keyword(s):

Magnetic Field ◽

Angular Momentum ◽

Magnetic Flux ◽

Large Scale ◽

Compact Object ◽

Light Curves ◽

Momentum Transport ◽

Local Magnetization ◽

Angular Momentum Transport ◽

The Impact

Context. Dwarf novæ (DNe) and low mass X-ray binaries (LMXBs) show eruptions that are thought to be due to a thermal-viscous instability in their accretion disk. These eruptions provide constraints on angular momentum transport mechanisms. Aims. We explore the idea that angular momentum transport could be controlled by the dynamical evolution of the large-scale magnetic field. We study the impact of different prescriptions for the magnetic field evolution on the dynamics of the disk. This is a first step in confronting the theory of magnetic field transport with observations. Methods. We developed a version of the disk instability model that evolves the density, the temperature, and the large-scale vertical magnetic flux simultaneously. We took into account the accretion driven by turbulence or by a magnetized outflow with prescriptions taken, respectively, from shearing box simulations or self-similar solutions of magnetized outflows. To evolve the magnetic flux, we used a toy model with physically motivated prescriptions that depend mainly on the local magnetization β, where β is the ratio of thermal pressure to magnetic pressure. Results. We find that allowing magnetic flux to be advected inwards provides the best agreement with DNe light curves. This leads to a hybrid configuration with an inner magnetized disk, driven by angular momentum losses to an MHD outflow, sharply transiting to an outer weakly-magnetized turbulent disk where the eruptions are triggered. The dynamical impact is equivalent to truncating a viscous disk so that it does not extend down to the compact object, with the truncation radius dependent on the magnetic flux and evolving as Ṁ−2/3. Conclusions. Models of DNe and LMXB light curves typically require the outer, viscous disk to be truncated in order to match the observations. There is no generic explanation for this truncation. We propose that it is a natural outcome of the presence of large-scale magnetic fields in both DNe and LMXBs, with the magnetic flux accumulating towards the center to produce a magnetized disk with a fast accretion timescale.

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Computation of Local Magnetization Curve from Visualized Magnetic Domain Dynamics By Bitter Method

2006 12th Biennial IEEE Conference on Electromagnetic Field Computation ◽

10.1109/cefc-06.2006.1633002 ◽

2006 ◽

Author(s):

T. Fujisaku ◽

Hisashi Endo ◽

S. Hayano ◽

Y. Saito

Keyword(s):

Magnetization Curve ◽

Magnetic Domain ◽

Local Magnetization ◽

Domain Dynamics

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A Monte Carlo simulation of steady state of 2D Ising model in temperature field

Modern Physics Letters B ◽

10.1142/s0217984916500226 ◽

2016 ◽

Vol 30 (04) ◽

pp. 1650022 ◽

Cited By ~ 1

Author(s):

Zeshun Chen ◽

Changming Xiao ◽

Zhen Yao

Keyword(s):

Monte Carlo ◽

Temperature Field ◽

Steady State ◽

Ising Model ◽

Low Temperatures ◽

Ferromagnetic State ◽

Model System ◽

Local Magnetization ◽

New Energy ◽

High And Low Temperatures

Supposing the Ising model system is placed in a temperature field with constant high and low temperatures on both sides, then the system will shift to a non-equilibrium steady state with a certain temperature gradient. With the assistance of local temperature, the steady state of two-dimensional Ising model is studied via the avenue of Monte Carlo simulations in this paper. It is found that the local energy and magnetization are continuous, but there is a sharp decline in the magnetization strength when the temperature falls into the range of 2.2–2.4. The local magnetization [Formula: see text], when the temperature [Formula: see text]. It is the indication that the system is in the ferromagnetic state. However, when [Formula: see text], [Formula: see text], and then the ferromagnetic state turns into the paramagnetic state. Furthermore, a completely new and special state of Ising model system and the corresponding material is possible if the high and low temperatures of the temperature field are larger and smaller than the critical value of the system, respectively. According to this material, the magnetic driving machine, from which a new energy source can be obtained, is qualitatively discussed at the end of this paper.

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