Micromagnetic simulation study of magnetization reversal in torus-shaped permalloy nanorings

2017 ◽  
Vol 31 (22) ◽  
pp. 1750162 ◽  
Author(s):  
Amaresh Chandra Mishra ◽  
R. Giri
Keyword(s):  
Hysteresis Loop ◽  
Simulation Study ◽  
Magnetization Reversal ◽  
Hysteresis Loops ◽  
Vortex State ◽  
Micromagnetic Simulation ◽  
Hysteresis Curve ◽  
Minor Radius ◽  
Maximum Value ◽  
Major Radius

Using micromagnetic simulation, the magnetization reversal of soft permalloy rings of torus shape with major radius R varying within 20–100 nm has been investigated. The minor radius r of the torus rings was increased from 5 nm up to a maximum value r[Formula: see text] such that R- r[Formula: see text] = 10 nm. Micromagnetic simulation of in-plane hysteresis curve of these nanorings revealed that in the case of very thin rings (r [Formula: see text] 10 nm), the remanent state is found to be an onion state, whereas for all other rings, the remanent state is a vortex state. The area of the hysteresis loop was found to be decreasing gradually with the increment of r. The normalized area under the hysteresis loops (A[Formula: see text]) increases initially with increment of r. It attains a maximum for a certain value of r = r0 and again decreases thereafter. This value r0 increases as we decrease R and as a result, this peak feature is hardly visible in the case of smaller rings (rings having small R).

Magnetic skyrmions in FePt nanoparticles having Reuleaux 3D geometry: a micromagnetic simulation study

Nanoscale ◽  
2019 ◽  
Vol 11 (42) ◽  
pp. 20102-20114 ◽  
Author(s):  
Vasileios D. Stavrou ◽  
Drosos Kourounis ◽  
Konstantinos Dimakopoulos ◽  
Ioannis Panagiotopoulos ◽  
Leonidas N. Gergidis
Keyword(s):  
Finite Element ◽  
Simulation Study ◽  
Magnetization Reversal ◽  
Magnetocrystalline Anisotropy ◽  
Micromagnetic Simulation ◽  
Fept Nanoparticles ◽  
External Fields ◽  
Micromagnetic Simulations ◽  
3D Geometry ◽  
Magnetic Skyrmions

The magnetization reversal in magnetic FePt nanoelements having Reuleaux 3D geometry is studied using Finite Element micromagnetic simulations. Multiple skyrmions are formed for a range of external fields and magnetocrystalline anisotropy values.

Magnetization reversal in crossed double elliptic permalloy nanodisks studied by micromagnetic simulation

2018 ◽  
Vol 32 (13) ◽  
pp. 1850156
Author(s):  
Amaresh Chandra Mishra ◽  
R. Giri
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Applied Magnetic Field ◽  
Magnetization Reversal ◽  
Major Axis ◽  
Vortex State ◽  
Micromagnetic Simulation ◽  
Minor Axis ◽  
Semi Major Axis ◽  
Saturation State

The remanent state of elliptical permalloy nanodisks depends on the orientation of the applied magnetic field with respect to the major and minor axes of the nanodisks [A. C. Mishra, Int. J. Mod. Phys. B 30, 1650192 (2016)]. The remanent state is usually an onion state if the external magnetic field is along the major axis, and is a vortex state if the external magnetic field is along the minor axis. In this work, we have analyzed the magnetization reversal of a crossed elliptic disk of permalloy using micromagnetic simulation. This is a new shape where two identical elliptic disks with semi-major axis of length a and semi-minor axis of length b intersect such that they are perpendicular to each other. If the value of b is very close to that of a, then the remanent state is a near saturation state. As the ratio a/b goes down, new complex remanent states are observed. The hysteresis loss is found to be decreased gradually with the increment of b for a given value of b.

Micromagnetic simulation of hysteresis loop of elliptic permalloy nanorings

2016 ◽  
Vol 30 (26) ◽  
pp. 1650192 ◽  
Author(s):  
Amaresh Chandra Mishra
Keyword(s):  
Magnetic Field ◽  
Hysteresis Loop ◽  
Magnetic Hysteresis ◽  
Major Axis ◽  
Micromagnetic Simulation ◽  
Hysteresis Curve ◽  
Semi Major Axis ◽  
Axis Length ◽  
20 Nm ◽  
The Magnetic Field

Magnetic hysteresis behavior of isotropic permalloy elliptic nanorings of outer semi-major axis length [Formula: see text] 100 nm and thickness [Formula: see text] 20 nm were studied with respect to the variation of two parameters: outer semiminor axis length [Formula: see text] and the difference between outer and inner dimensions [Formula: see text]. The outer semiminor axis length [Formula: see text] varied from 90 nm to 20 nm which covers from nearly circular nanoring to elliptic nanoring of high aspect ratio. The value of [Formula: see text] varied in steps of 10 nm. Micromagnetic simulation of in-plane hysteresis curve of these nanorings revealed that the remanent state of all of these elliptic rings are onion states if the magnetic field is applied along the longer side of the elliptic rings. If the magnetic field is applied along the shorter side, then the remanent states turn out to be vortex state. The hysteresis loss indicated by area of the hysteresis loop was found to be decreasing gradually with the increment of either [Formula: see text] or [Formula: see text]. On the other hand, the remanent magnetization increased with increment of [Formula: see text] but decreased with the increment of [Formula: see text]. The changes were attributed to three parameters mainly: inner curvature, exchange energy and demagnetization energy. The changes in loop area were discussed in light of variation of these three parameters.

Micromagnetic Simulation of Asymmetrical CoFe Nanorings

2012 ◽  
Vol 538-541 ◽  
pp. 529-533
Author(s):  
Zhen Gang Guo ◽  
Li Qing Pan ◽  
Hong Mei Qiu ◽  
Xue Dan Zhao ◽  
Li Hong Yang
Keyword(s):  
Magnetic Field ◽  
Domain Wall ◽  
Applied Magnetic Field ◽  
Magnetization Reversal ◽  
Vortex State ◽  
Micromagnetic Simulation ◽  
Micromagnetic Simulations ◽  
Vortex States

Domain wall motions and magnetization reversal processes in the nanoscale asymmetrical Co50Fe50rings have been studied using micromagnetic simulations. The results reveal that the switching fields and the plateau width of vortex state can be tuned through changing the asymmetrical parameter of magnetic nanorings. The chirality of vortex states can be easily controlled by the orientation of the applied magnetic field.

scholarly journals Micromagnetic Simulations of Fe and Ni Nanodot Arrays Surrounded by Magnetic or Non-Magnetic Matrices

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 349
Author(s):  
Devika Sudsom ◽  
Andrea Ehrmann
Keyword(s):  
Magnetic Materials ◽  
Data Storage ◽  
Magnetization Reversal ◽  
Hysteresis Loops ◽  
Object Oriented ◽  
Basic Research ◽  
Memory Systems ◽  
The Other ◽  
Micromagnetic Simulations ◽  
Nanodot Arrays

Combining clusters of magnetic materials with a matrix of other magnetic materials is very interesting for basic research because new, possibly technologically applicable magnetic properties or magnetization reversal processes may be found. Here we report on different arrays combining iron and nickel, for example, by surrounding circular nanodots of one material with a matrix of the other or by combining iron and nickel nanodots in air. Micromagnetic simulations were performed using the OOMMF (Object Oriented MicroMagnetic Framework). Our results show that magnetization reversal processes are strongly influenced by neighboring nanodots and the magnetic matrix by which the nanodots are surrounded, respectively, which becomes macroscopically visible by several steps along the slopes of the hysteresis loops. Such material combinations allow for preparing quaternary memory systems, and are thus highly relevant for applications in data storage and processing.

In Situ Testing and X Rays Radiation Effects of Pt/Bi3.15Nd0.85Ti3O12/Pt Ferroelectric Capacitors

2013 ◽  
Vol 712-715 ◽  
pp. 293-297
Author(s):  
Li Li
Keyword(s):  
Radiation Effects ◽  
Hysteresis Loops ◽  
Electrical Performance ◽  
Hysteresis Curve ◽  
X Rays ◽  
Shanghai Synchrotron Radiation Facility ◽  
X Ray ◽  
In The Beginning ◽  
Ferroelectric Capacitors

Pt/Bi3.15Nd0.85Ti3O12(BNT)/Pt ferroelectric capacitors were monitored using in situ X-ray irradiation with 10 keV at BL14B1 beamline (Shanghai Synchrotron Radiation Facility). BL14B1 combined with a ferroelectric analyzer enabled measurements in situ of electrical performance. The hysteresis curve (PE) of distortion depended on the polarization during irradiation, but the diffracted intensities of the (117) peak did not change in the beginning. ThePEcurve had a negligible change from 2.09×109Gy to 4.45×109Gy. Finally, bothPrandPr+very rapidly increased, but the intensities of (117) decreased. The hysteresis loops were remarkably deformed at the maximum total dose of 4.87×109Gy.

scholarly journals Asymmetric Magnetization Reversal in Exchange-Biased Hysteresis Loops

2000 ◽  
Vol 84 (17) ◽  
pp. 3986-3989 ◽  
Author(s):  
M. R. Fitzsimmons ◽  
P. Yashar ◽  
C. Leighton ◽  
Ivan K. Schuller ◽  
J. Nogués ◽  
...  
Keyword(s):  
Magnetization Reversal ◽  
Hysteresis Loops

A polycrystal hysteresis model for ferroelectric ceramics

2006 ◽  
Vol 462 (2069) ◽  
pp. 1573-1592 ◽  
Author(s):  
Y Su ◽  
G.J Weng
Keyword(s):  
Electric Field ◽  
Hysteresis Loop ◽  
Ferroelectric Properties ◽  
Electric Displacement ◽  
Hysteresis Loops ◽  
Ferroelectric Ceramics ◽  
Domain Growth ◽  
Thermodynamic Approach ◽  
Hysteresis Model ◽  
Self Consistent

Most key elements of ferroelectric properties are defined through the hysteresis loops. For a ferroelectric ceramic, its loop is contributed collectively by its constituent grains, each having its own hysteresis loop when the ceramic polycrystal is under a cyclic electric field. In this paper, we propose a polycrystal hysteresis model so that the hysteresis loop of a ceramic can be calculated from the loops of its constituent grains. In this model a micromechanics-based thermodynamic approach is developed to determine the hysteresis behaviour of the constituent grains, and a self-consistent scheme is introduced to translate these behaviours to the polycrystal level. This theory differs from the classical phenomenological ones in that it is a micromechanics-based thermodynamic approach and it can provide the evolution of new domain concentration among the constituent grains. It also differs from some recent micromechanics studies in its secant form of self-consistent formulation and in its application of irreversible thermodynamics to derive the kinetic equation of domain growth. To put this two-level micromechanics theory in perspective, it is applied to a ceramic PLZT 8/65/35, to calculate its hysteresis loop between the electric displacement and the electric field ( D versus E ), and the butterfly-shaped longitudinal strain versus the electric field relation ( ϵ versus E ). The calculated results are found to be in good quantitative agreement with the test data. The corresponding evolution of new domain concentration c 1 and the individual hysteresis loops of several selected grains—along with those of the overall polycrystal—are also illustrated.

scholarly journals CMOS Realization of All-Positive Pinched Hysteresis Loops

Complexity ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
B. J. Maundy ◽  
A. S. Elwakil ◽  
C. Psychalinos
Keyword(s):  
Hysteresis Loop ◽  
Detailed Analysis ◽  
Hysteresis Loops ◽  
Nonlinear Circuits ◽  
Experimental Results ◽  
First Order ◽  
Pinched Hysteresis Loop ◽  
A Charge ◽  
Pinched Hysteresis ◽  
Nmos Transistors

Two novel nonlinear circuits that exhibit an all-positive pinched hysteresis loop are proposed. These circuits employ two NMOS transistors, one of which operates in its triode region, in addition to two first-order filter sections. We show the equivalency to a charge-controlled resistance (memristance) in a decremental state via detailed analysis. Simulation and experimental results verify the proposed theory.

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