The effect of Dzyaloshinskii–Moriya interaction on direct and backward transition between magnetic states of Pt/Co/Ir/Co/Pr synthetic ferrimagnet

2021 ◽  
Vol 6 (3) ◽  
pp. 167-178
Author(s):  
Artem D. Talantsev ◽  
Ekaterina I. Kunitsyna ◽  
Roman B. Morgunov
Keyword(s):  
Thin Layer ◽  
Domain Structure ◽  
Magnetization Reversal ◽  
Domain Walls ◽  
Ferromagnetic Layers ◽  
Magneto Optical Kerr Effect ◽  
Magnetic States ◽  
Fluctuation Fields ◽  
Moriya Interaction ◽  
Effect Technique

In this paper, we present the study of domain structure accompanying interstate transitions in Pt/Co/Ir/Co/Pr synthetic ferrimagnet (SF) of 1.1 nm thick and 0.6 – 1.0 nm thin ferromagnetic Co layers. Variation in the thickness of the thin layer causes noticeable changes in the domain structure and mechanism of magnetization reversal revealed by MOKE (Magneto-Optical Kerr Effect) technique. Magnetization reversal includes coherent rotation of magnetization of the ferromagnetic layers, generation of magnetic nuclei, spreading of domain walls (DW), and development of areas similar with strip domains, dependently on thickness of the thin layer. Inequivalence of the direct and backward transitions between magnetic states of SF with parallel and antiparallel magnetizations was observed in sample with thin layer thicknesses 0.8 nm and 1.0 nm. Asymmetry of the transition between these states is expressed in difference fluctuation fields and shapes of reversal magnetization nucleus contributing to the correspondent forward and backward transitions. We proposed simple model based on asymmetry of Dzyaloshinskii–Moriya interaction. This model explains competition between nucleation and domain wall propagation due to increase/decrease of the DW energy dependently on direction of the spin rotation into the DW in respect to external field.

MAGNETIC ELEMENTS OF NEURAL NETWORKS. PROPERTIES OF MAGNETIC INHOMOGENEITIES IN RESTRICTED GEOMETRIES

2021 ◽  
Vol 0 (1) ◽  
pp. 81-86
Author(s):  
A.R. MINIBAEVA ◽  
◽  
Z.V. GAREEVA ◽  
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Magnetic Anisotropy ◽  
Domain Structure ◽  
Magnetic State ◽  
Magnetic Nanostructures ◽  
External Factors ◽  
Magnetic Elements ◽  
Magnetic States ◽  
Moriya Interaction

This paper discusses the prospects for using magnetic nanostructures as elements of neural networks. At present neural network learning programs are actively used in analyzing and processing large data arrays; however, the development of computer technologies based on the neural network principle still remains open. Possibilities for using magnetic elements as physical carriers of information bits in these systems attract much attention from researchers and technologists due to the presence of several easily controlled parameters (order parameter) in the magnetic system, possibilities for the dimensionality reduction in magnetic elements by using magnetic nanostructures (domain boundaries, vortices, ckyrmions), superquick switching between magnetic states and some other factors. One of the key aspects of research in this regard is to determine basic controlled magnetic parameters in restricted geometries and to identify ways of controlling these parameters through internal and external factors. The paper presents a research on the magnetic ground state in restricted geometries. It deals with the magnetic state rebuilding in the system under changes in both external factors (applied magnetic field, sample dimensions) and internal ones (magnetic anisotropy constant, Dzyaloshinskii-Moriya interaction constant). Calculations were performed within the framework of micromagnetic modelling using the Object Oriented MicroMagnetic Framework ( OOMMF) sogtware. It is shown that the anisotropic exchange interaction (Dzyaloshinskii-Moriya interaction) has a significant effect on the magnetization distribution in restricted geometries. Namely, when changing the value of the Dzyaloshinskii-Moriya constant in the system with uniaxial magnetic anisotropy there is a series of phase transitions observed between magnetic states of different types: transitions from the homogenous magnetic state into the skyrmion-type vortex state (domain structure with the skyrmion-type unidomain state) with subsequent domain structure reversal when changing the value of the Dzyaloshinskii-Moriya constant. In the case of magnetic anisotropy of easy -axis type, chirality and properties of the structures in question do not depend on the constant symbol of the Dzyaloshinskii-Moriya interaction.

Micromagnetic Simulation of CoFe Magnetic Nanorings: Switching Behavior in External Magnetic Field

2013 ◽  
Vol 710 ◽  
pp. 80-84 ◽  
Author(s):  
Zhen Gang Guo ◽  
Li Qing Pan ◽  
Hong Mei Qiu ◽  
M. Yasir Rafique ◽  
Shuai Zeng
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetization Reversal ◽  
Domain Walls ◽  
Vortex State ◽  
Switching Behavior ◽  
Switching Field ◽  
Reversal Process ◽  
Magnetic States ◽  
Magnetization Processes

The magnetization reversal processes of magnetic nanorings (Co50Fe50) with different geometric shapes are investigated. In addition to the expected onion and vortex magnetization states, other metastable states are observed in the magnetization processes. We anatomize the formation and transition of magnetic states, and the propagation and annihilation of domain walls in the reversal process through the dynamic picture. Phase diagrams for the magnetization switching behavior depending on the geometric parameters are presented. The simulation shows that the vortex state is stabilized in thick and narrow rings. The switching field from vortex to onion states turns out to increase with thickness and decrease with width and diameter.

Influence of Magnetic Field of Super High Frequency on Hysteretic Properties of Soft Magnetic Microwires

2014 ◽  
Vol 93 ◽  
pp. 203-207
Author(s):  
Alexander Chizhik ◽  
Julian Gonzalez ◽  
Arkadi Zhukov ◽  
Andrzej Stupakiewicz ◽  
Andrzej Maziewski
Keyword(s):  
Magnetic Field ◽  
High Frequency ◽  
Domain Walls ◽  
Soft Magnetic ◽  
Circular Magnetic Field ◽  
Asymmetric Shape ◽  
Magneto Optical Kerr Effect ◽  
Magnetic States ◽  
Super High Frequency ◽  
Hysteretic Properties

Normal 0 21 false false false MicrosoftInternetExplorer4 The influence of super high frequency (SHF) circular magnetic field on magnetization reversal in the Co-rich glass covered microwire has been investigated. The study has been performed by magneto-optical Kerr effect (MOKE) technique. It was found that the presence of the SHF field causes the change of the re-magnetization mechanism – the rotation of the magnetization is observed instead of domain walls motion. Also the hysteresis loop has an asymmetric shape that confirms the co-existence of the stable and meta-stable helical magnetic states in the surface of microwires. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;}

scholarly journals Subsystem domination influence on magnetization reversal in designed magnetic patterns in ferrimagnetic Tb/Co multilayers

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Łukasz Frąckowiak ◽  
Feliks Stobiecki ◽  
Gabriel David Chaves-O’Flynn ◽  
Maciej Urbaniak ◽  
Marek Schmidt ◽  
...  
Keyword(s):  
Domain Wall ◽  
Magnetization Reversal ◽  
Domain Walls ◽  
Compensation Point ◽  
Relative Sign ◽  
Reversal Process ◽  
Effective Magnetization ◽  
Domain Wall Propagation ◽  
Characteristic Features ◽  
Magnetization Reversal Process

AbstractRecent results showed that the ferrimagnetic compensation point and other characteristic features of Tb/Co ferrimagnetic multilayers can be tailored by He+ ion bombardment. With appropriate choices of the He+ ion dose, we prepared two types of lattices composed of squares with either Tb or Co domination. The magnetization reversal of the first lattice is similar to that seen in ferromagnetic heterostructures consisting of areas with different switching fields. However, in the second lattice, the creation of domains without accompanying domain walls is possible. These domain patterns are particularly stable because they simultaneously lower the demagnetizing energy and the energy associated with the presence of domain walls (exchange and anisotropy). For both lattices, studies of magnetization reversal show that this process takes place by the propagation of the domain walls. If they are not present at the onset, the reversal starts from the nucleation of reversed domains and it is followed by domain wall propagation. The magnetization reversal process does not depend significantly on the relative sign of the effective magnetization in areas separated by domain walls.

scholarly journals Domain Structure and Magnetization Reversal Micromechanisms in Quasi-Two-Dimensional Exchange-Biased Nanomagnetics

2018 ◽  
Vol 60 (11) ◽  
pp. 2222-2230 ◽  
Author(s):  
V. S. Gornakov ◽  
I. V. Shashkov ◽  
M. A. Lebyodkin ◽  
T. A. Lebedkina
Keyword(s):  
Domain Structure ◽  
Magnetization Reversal ◽  
Two Dimensional

scholarly journals Control of domain structure and magnetization reversal in thick Co/Pt multilayers

2019 ◽  
Vol 99 (2) ◽  
Author(s):  
L. Fallarino ◽  
A. Oelschlägel ◽  
J. A. Arregi ◽  
A. Bashkatov ◽  
F. Samad ◽  
...  
Keyword(s):  
Domain Structure ◽  
Magnetization Reversal

scholarly journals Domain Diversity and Polarization Switching in Amino Acid β-Glycine

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1223 ◽  
Author(s):  
Daria Vasileva ◽  
Semen Vasilev ◽  
Andrei L. Kholkin ◽  
Vladimir Ya. Shur
Keyword(s):  
Amino Acid ◽  
Domain Structure ◽  
Lead Zirconate Titanate ◽  
Domain Walls ◽  
Piezoelectric Materials ◽  
Polarization Switching ◽  
Building Blocks ◽  
Crystallographic Structure ◽  
Processing Temperature ◽  
Sensors And Actuators

Piezoelectric materials based on lead zirconate titanate are widely used in sensors and actuators. However, their application is limited because of high processing temperature, brittleness, lack of conformal deposition and, more importantly, intrinsic incompatibility with biological environments. Recent studies on bioorganic piezoelectrics have demonstrated their potential in these applications, essentially due to using the same building blocks as those used by nature. In this work, we used piezoresponse force microscopy (PFM) to study the domain structures and polarization reversal in the smallest amino acid glycine, which recently attracted a lot of attention due to its strong shear piezoelectric activity. In this uniaxial ferroelectric, a diverse domain structure that includes both 180° and charged domain walls was observed, as well as domain wall kinks related to peculiar growth and crystallographic structure of this material. Local polarization switching was studied by applying a bias voltage to the PFM tip, and the possibility to control the resulting domain structure was demonstrated. This study has shown that the as-grown domain structure and changes in the electric field in glycine are qualitatively similar to those found in the uniaxial inorganic ferroelectrics.

Observations of Domain Structure at Initial Growth Stage of PbTiO3 Thin Films Grown by Mocvd

1999 ◽  
Vol 596 ◽  
Author(s):  
H. Fujisawa ◽  
M. Shimizu ◽  
H. Niu ◽  
K. Honda ◽  
S Ohtani
Keyword(s):  
Thin Films ◽  
Domain Structure ◽  
Growth Stage ◽  
Domain Walls ◽  
Chemical Vapor ◽  
Initial Growth ◽  
Continuous Film ◽  
Cross Sectional ◽  
Initial Growth Stage ◽  
Transmission Electron

AbstractDomain structure and growth mechanism of PbTiO3 thin films were investigated using a transmission electron microscopy(TEM) from the viewpoint of size effects. At initial growth stage of (111)-oriented PbTiO3 films prepared by metalorganic chemical vapor deposition(MOCVD), triangle-shaped islands were grown on Pt(111)/SiO2/Si before becoming a continuous film. Triangular islands grew gradually in a lateral dimension. This means that PbTiO3 films grew two-dimensionally at initial growth stage. In cross-sectional TEM photomicrographs, (101)-twin boundaries (90° domain walls) and inclination of {110} or {101}-plane were observed in PbTiO3 islands. This result indicates that such small PbTiO3 islands have a tetragonal structure and could have spontaneous polarization. The minimum island which had 90° domain walls was 10nm high and 18nm wide.

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