scholarly journals On the Effect of Magnetostatic Interaction on the Collective Motion of Vortex Domain Walls in a Pair of Nanostripes

2019 ◽  
Vol 256 (10) ◽  
pp. 1900113
Author(s):  
Vitaly A. Orlov ◽  
Anatoly A. Ivanov ◽  
Irina N. Orlova
Keyword(s):  
Domain Walls ◽  
Collective Motion ◽  
Magnetostatic Interaction

Current-induced collective motion of 180° and 360° domain walls in double nanowires system

2013 ◽  
Vol 347 ◽  
pp. 124-130 ◽  
Author(s):  
Senfu Zhang ◽  
Qiyuan Zhu ◽  
Congpu Mu ◽  
Yi Zhang ◽  
Qingfang Liu ◽  
...  
Keyword(s):  
Domain Walls ◽  
Collective Motion

Magnetic Force Microscopic Study on Domain-Wall Molecules in NiFe Nano Rings

2009 ◽  
Vol 152-153 ◽  
pp. 529-532
Author(s):  
Kohei Sasage ◽  
Naoya Okamoto ◽  
Hana Tsujikawa ◽  
Takehiro Yamaoka ◽  
Eiji Saitoh
Keyword(s):  
Magnetic Field ◽  
Magnetic Force Microscopy ◽  
Magnetic Force ◽  
Domain Walls ◽  
Magnetic Domain ◽  
Threshold Value ◽  
Magnetostatic Interaction ◽  
Stray Magnetic Field ◽  
Force Microscopy ◽  
Magnetic Domain Walls

A pair of magnetic domain walls (DWs) in ferromagnetic NiFe rings has been investigated in terms of the magnetic force microscopy (MFM). When the distance between the rings d is greater than a threshold value dth, MFM signals indicate that a DW in the ring is dragged due to a stray magnetic field from an MFM probe tip. When d < dth, this drag signals disappears; DWs are bound to each other by the DW-DW interaction. This transition can be argued in terms of the competition between the DW-DW magnetostatic interaction and the DW-drag potential. From the d-dependent MFM data, the DW-drag potential was estimated.

Mechanisms of Pinning of Domain Walls in Nanowires

2010 ◽  
Vol 168-169 ◽  
pp. 230-233 ◽  
Author(s):  
A.A. Ivanov ◽  
V.A. Orlov ◽  
N.N. Podolsky
Keyword(s):  
Numerical Methods ◽  
Domain Wall ◽  
Coercive Force ◽  
Magnetization Curve ◽  
Domain Walls ◽  
Magnetostatic Interaction ◽  
Crystallographic Anisotropy ◽  
Domain Wall Pinning ◽  
Force Profile ◽  
Pinning Of Domain Walls

Analytical and numerical methods are used to study the process of motion of domain walls in an individual nanowire consisting of ferromagnetic crystallites with a chaotic crystallographic anisotropy. The influence of magnetostatic interaction on the motion is considered. The force profile of the domain wall pinning, caused by stochastic crystallographic anisotropy, is examined. The magnetization curve is analytically constructed and the coercive force is calculated. The Barkhausen jumps of domain walls are investigated. The result is verified by numerically modeling.

scholarly journals Bursts of activity in collective cell migration

2016 ◽  
Vol 113 (41) ◽  
pp. 11408-11413 ◽  
Author(s):  
Oleksandr Chepizhko ◽  
Costanza Giampietro ◽  
Eleonora Mastrapasqua ◽  
Mehdi Nourazar ◽  
Miriam Ascagni ◽  
...  
Keyword(s):  
Cell Migration ◽  
Scaling Laws ◽  
Domain Walls ◽  
Collective Motion ◽  
Cell Types ◽  
Living Cells ◽  
Collective Cell Migration ◽  
Relaxation Dynamics ◽  
Active Particles ◽  
Different Cell Types

Dense monolayers of living cells display intriguing relaxation dynamics, reminiscent of soft and glassy materials close to the jamming transition, and migrate collectively when space is available, as in wound healing or in cancer invasion. Here we show that collective cell migration occurs in bursts that are similar to those recorded in the propagation of cracks, fluid fronts in porous media, and ferromagnetic domain walls. In analogy with these systems, the distribution of activity bursts displays scaling laws that are universal in different cell types and for cells moving on different substrates. The main features of the invasion dynamics are quantitatively captured by a model of interacting active particles moving in a disordered landscape. Our results illustrate that collective motion of living cells is analogous to the corresponding dynamics in driven, but inanimate, systems.

The direct determination of magnetic domain wall profiles using a split detector STEM

1978 ◽  
Vol 36 (1) ◽  
pp. 466-467
Author(s):  
J.N. Chapman ◽  
P.E. Batson ◽  
E.M. Waddell ◽  
R.P. Ferrier
Keyword(s):  
Electron Microscope ◽  
Domain Wall ◽  
Transmission Electron Microscope ◽  
Domain Walls ◽  
Photographic Plate ◽  
Magnetic Domain ◽  
Direct Determination ◽  
Quantitative Information ◽  
Scanning Transmission Electron Microscope ◽  
Transmission Electron

By far the most commonly used mode of Lorentz microscopy in the examination of ferromagnetic thin films is the Fresnel or defocus mode. Use of this mode in the conventional transmission electron microscope (CTEM) is straightforward and immediately reveals the existence of all domain walls present. However, if such quantitative information as the domain wall profile is required, the technique suffers from several disadvantages. These include the inability to directly observe fine image detail on the viewing screen because of the stringent illumination coherence requirements, the difficulty of accurately translating part of a photographic plate into quantitative electron intensity data, and, perhaps most severe, the difficulty of interpreting this data. One solution to the first-named problem is to use a CTEM equipped with a field emission gun (FEG) (Inoue, Harada and Yamamoto 1977) whilst a second is to use the equivalent mode of image formation in a scanning transmission electron microscope (STEM) (Chapman, Batson, Waddell, Ferrier and Craven 1977), a technique which largely overcomes the second-named problem as well.

Lorentz microscopy study of magnetic domain walls in Fe-Cr-Co alloys

1978 ◽  
Vol 36 (1) ◽  
pp. 462-463
Author(s):  
Yalcin Belli
Keyword(s):  
Domain Walls ◽  
Magnetic Domain ◽  
Microscopy Study ◽  
Ferromagnetic Phase ◽  
Stable Phase ◽  
Magnetic Domains ◽  
Lorentz Microscopy ◽  
Magnetic Hardening ◽  
Electron Microscopes ◽  
Co Alloys

Fe-Cr-Co alloys have great technological potential to replace Alnico alloys as hard magnets. The relationship between the microstructures and the magnetic properties has been recently established for some of these alloys. The magnetic hardening has been attributed to the decomposition of the high temperature stable phase (α) into an elongated Fe-rich ferromagnetic phase (α1) and a weakly magnetic or non-magnetic Cr-rich phase (α2). The relationships between magnetic domains and domain walls and these different phases are yet to be understood. The TEM has been used to ascertain the mechanism of magnetic hardening for the first time in these alloys. The present paper describes the magnetic domain structure and the magnetization reversal processes in some of these multiphase materials. Microstructures to change properties resulting from, (i) isothermal aging, (ii) thermomagnetic treatment (TMT) and (iii) TMT + stepaging have been chosen for this investigation. The Jem-7A and Philips EM-301 transmission electron microscopes operating at 100 kV have been used for the Lorentz microscopy study of the magnetic domains and their interactions with the finely dispersed precipitate phases.

Temperature Dependence of Magnetic Domains and Wall Structures

1972 ◽  
Vol 30 ◽  
pp. 496-497
Author(s):  
Sonoko Tsukahara ◽  
Tadami Taoka ◽  
Hisao Nishizawa
Keyword(s):  
Temperature Dependence ◽  
Domain Walls ◽  
Magnetic Domain ◽  
Iron Film ◽  
Objective Lens ◽  
Lorentz Microscopy ◽  
Domain Structures ◽  
Wall Structures ◽  
Crystal Films ◽  
Metallurgical Structure

The high voltage Lorentz microscopy was successfully used to observe changes with temperature; of domain structures and metallurgical structures in an iron film set on the hot stage combined with a goniometer. The microscope used was the JEM-1000 EM which was operated with the objective lens current cut off to eliminate the magnetic field in the specimen position. Single crystal films with an (001) plane were prepared by the epitaxial growth of evaporated iron on a cleaved (001) plane of a rocksalt substrate. They had a uniform thickness from 1000 to 7000 Å.The figure shows the temperature dependence of magnetic domain structure with its corresponding deflection pattern and metallurgical structure observed in a 4500 Å iron film. In general, with increase of temperature, the straight domain walls decrease in their width (at 400°C), curve in an iregular shape (600°C) and then vanish (790°C). The ripple structures with cross-tie walls are observed below the Curie temperature.

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