scholarly journals Controlling the stability of both the structure and velocity of domain walls in magnetic nanowires

2016 ◽  
Vol 109 (6) ◽  
pp. 062405 ◽  
Author(s):  
J. Brandão ◽  
D. Atkinson
Keyword(s):  
Domain Walls ◽  
Magnetic Nanowires ◽  
The Stability

scholarly journals Information storage in permalloy modulated magnetic nanowires

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Guidobeth Sáez ◽  
Pablo Díaz ◽  
Eduardo Cisternas ◽  
Eugenio E. Vogel ◽  
Juan Escrig
Keyword(s):  
Magnetic Material ◽  
Phase Diagram ◽  
Magnetic Fields ◽  
Domain Walls ◽  
Wire Diameter ◽  
Information Storage ◽  
Magnetic Nanowires ◽  
The Wire ◽  
The Stability ◽  
Cylindrical Wire

AbstractA long piece of magnetic material shaped as a central cylindrical wire (diameter $$d=50$$ d = 50 nm) with two wider coaxial cylindrical portions (diameter $$D=90$$ D = 90 nm and thickness $$t=100$$ t = 100 nm) defines a bimodulated nanowire. Micromagnetism is invoked to study the equilibrium energy of the system under the variations of the positions of the modulations along the wire. The system can be thought of as composed of five independent elements (3 segments and 2 modulations) leading to $$2^5=32$$ 2 5 = 32 possible different magnetic configurations, which will be later simplified to 4. We investigate the stability of the configurations depending on the positions of the modulations. The relative chirality of the modulations has negligible contributions to the energy and they have no effect on the stability of the stored configuration. However, the modulations are extremely important in pinning the domain walls that lead to consider each segment as independent from the rest. A phase diagram reporting the stability of the inscribed magnetic configurations is produced. The stability of the system was then tested under the action of external magnetic fields and it was found that more than 50 mT are necessary to alter the inscribed information. The main purpose of this paper is to find whether a prototype like this can be complemented to be used as a magnetic key or to store information in the form of firmware. Present results indicate that both possibilities are feasible.

scholarly journals Information storage in permalloy modulated magnetic nanowires

2021 ◽  
Author(s):  
Guidobeth Sáez ◽  
Pablo Díaz ◽  
Eduardo Cisternas ◽  
Eugenio E. Vogel ◽  
Juan Escrig
Keyword(s):  
Magnetic Material ◽  
Phase Diagram ◽  
Magnetic Fields ◽  
Domain Walls ◽  
Wire Diameter ◽  
Information Storage ◽  
Magnetic Nanowires ◽  
The Wire ◽  
The Stability ◽  
Cylindrical Wire

Abstract A long piece of magnetic material shaped as a central cylindrical wire (diameter d = 50 nm) with two wider coaxial cylindrical portions (diameter D = 90 nm and thickness t = 100 nm) defines a bimodulated nanowire. Micromagnetism is invoked to study the equilibrium energy of the system under the variations of the positions of the modulations along the wire. The system can be thought of as composed of 5 independent elements (3 segments and 2 modulations) leading to 25 = 32 different magnetic configurations. We investigate the stability of the configurations depending on the positions of the modulations. The relative chirality of the modulations has negligible contributions to the energy and they have no effect in the stability of the stored configuration. However, the modulations are extremely important in pinning the domain walls that lead to consider each segment as independent from the rest. A phase diagram reporting the stability of the inscribed magnetic configurations is produced. The stability of the system was then tested under the action of external magnetic fields and it is found that more than 50 mT are necessary to alter the inscribed information. The main purpose of this paper is to find weather a prototype like this can complemented to be used as firmware or magnetic keys. Present results indicate that this is feasible.

scholarly journals Magnetic Configurations in Modulated Cylindrical Nanowires

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 600
Author(s):  
Cristina Bran ◽  
Jose Angel Fernandez-Roldan ◽  
Rafael P. del Real ◽  
Agustina Asenjo ◽  
Oksana Chubykalo-Fesenko ◽  
...  
Keyword(s):  
Domain Walls ◽  
Magnetocrystalline Anisotropy ◽  
Logic Gates ◽  
Local Domain ◽  
Magnetic Nanowires ◽  
Precise Control ◽  
Magnetic Layers ◽  
State Present ◽  
Circular Domains ◽  
3D Applications

Cylindrical magnetic nanowires show great potential for 3D applications such as magnetic recording, shift registers, and logic gates, as well as in sensing architectures or biomedicine. Their cylindrical geometry leads to interesting properties of the local domain structure, leading to multifunctional responses to magnetic fields and electric currents, mechanical stresses, or thermal gradients. This review article is summarizing the work carried out in our group on the fabrication and magnetic characterization of cylindrical magnetic nanowires with modulated geometry and anisotropy. The nanowires are prepared by electrochemical methods allowing the fabrication of magnetic nanowires with precise control over geometry, morphology, and composition. Different routes to control the magnetization configuration and its dynamics through the geometry and magnetocrystalline anisotropy are presented. The diameter modulations change the typical single domain state present in cubic nanowires, providing the possibility to confine or pin circular domains or domain walls in each segment. The control and stabilization of domains and domain walls in cylindrical wires have been achieved in multisegmented structures by alternating magnetic segments of different magnetic properties (producing alternative anisotropy) or with non-magnetic layers. The results point out the relevance of the geometry and magnetocrystalline anisotropy to promote the occurrence of stable magnetochiral structures and provide further information for the design of cylindrical nanowires for multiple applications.

scholarly journals The Stability of Fake Flat Domain Walls on Kähler Manifold

2016 ◽  
Vol 739 ◽  
pp. 012043
Author(s):  
F T Akbar ◽  
R N Wijaya ◽  
B E Gunara
Keyword(s):  
Domain Walls ◽  
Kähler Manifold ◽  
Kahler Manifold ◽  
The Stability

scholarly journals Probing domain walls in cylindrical magnetic nanowires with electron holography

2017 ◽  
Vol 903 ◽  
pp. 012055 ◽  
Author(s):  
M Staňo ◽  
S Jamet ◽  
J C Toussaint ◽  
S Bochmann ◽  
J Bachmann ◽  
...  
Keyword(s):  
Domain Walls ◽  
Electron Holography ◽  
Magnetic Nanowires

scholarly journals Stiffness in vortex—like structures due to chirality-domains within a coupled helical rare-earth superlattice

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Amitesh Paul
Keyword(s):  
Rare Earth ◽  
Domain Walls ◽  
Topological Defects ◽  
Magnetic Ordering ◽  
Direct Consequence ◽  
Magnetic Vortex ◽  
Range Magnetic Order ◽  
Wide Range ◽  
Out Of Plane ◽  
The Stability

Abstract Vortex domain walls poses chirality or ‘handedness’ which can be exploited to act as memory units by changing their polarity with electric field or driving/manupulating the vortex itself by electric currents in multiferroics. Recently, domain walls formed by one dimensional array of vortex—like structures have been theoretically predicted to exist in disordered rare-earth helical magnets with topological defects. Here, in this report, we have used a combination of two rare-earth metals, e.g."Equation missing" superlattice that leads to long range magnetic order despite their competing anisotropies along the out-of-plane (Er) and in-plane (Tb) directions. Probing the vertically correlated magnetic structures by off-specular polarized neutron scattering we confirm the existence of such magnetic vortex—like domains associated with magnetic helical ordering within the Er layers. The vortex—like structures are predicted to have opposite chirality, side—by—side and are fairly unaffected by the introduction of magnetic ordering between the interfacial Tb layers and also with the increase in magnetic field which is a direct consequence of screening of the vorticity in the system due to a helical background. Overall, the stability of these vortices over a wide range of temperatures, fields and interfacial coupling, opens up the opportunity for fundamental chiral spintronics in unconventional systems.

Behavior of Magnetic Domains in Single Magnetic Nanowire with Shallow Trench along Length Direction Observed by Magnetic Force Microscopy

2013 ◽  
Vol 1527 ◽  
Author(s):  
Mitsunobu Okuda ◽  
Yasuyoshi Miyamoto ◽  
Eiichi Miyashita ◽  
Naoto Hayashi
Keyword(s):  
Domain Walls ◽  
Hard Disk Drives ◽  
Magnetic Domain ◽  
Magnetic Memory ◽  
Magnetic Nanowires ◽  
Magnetic Domains ◽  
Electric Circuits ◽  
Recording Density ◽  
Magnetic Nanowire ◽  
Length Direction

ABSTRACTWe have proposed new magnetic memories using parallel-aligned nanowires without mechanical moving parts, in order to achieve the ultra high transfer rate of more than 144 Gbps for Super Hi-Vision TV. In the magnetic memory using nanowires, the data are stored as the magnetic domains with up or down magnetization in magnetic nanowires, and the domains are shifted quite faster by applying optimum current along the nanowire direction for data writing and reading purpose. Since the electric circuits and the insulation space between the neighbor nanowires are necessary for moving the magnetic domain walls, the areal recording density is essentially reduced as compared with that of conventional hard disk drives. In this study, in order to increase the areal recording density of magnetic nanowire memory, we have tried to act one magnetic nanowire as the virtual multiple data tracks. The shallow scratched trench was introduced using scanning probe microscopy along the length direction on the surface of a single nanowire to form multiple internal tracks, and we have succeeded in realizing a couple of virtual tracks states.

scholarly journals Transforming understanding of paleomagnetic recording: Insights from experimental observations of laboratory aged thermal remanences

2020 ◽  
Author(s):  
Lisa Tauxe ◽  
Christeanne Santos ◽  
Xiang Zhao ◽  
Andrew Roberts
Keyword(s):  
Magnetic Field ◽  
Domain Walls ◽  
Vortex State ◽  
Estimation Methods ◽  
Zero Field ◽  
Ideal Behavior ◽  
Temperature Spectrum ◽  
Single Vortex ◽  
Thermal Origin ◽  
The Stability

<p>Néel theory (doi: 10.1080/0001873550010120 ) predicts that natural remanent magnetizations (NRMs) of thermal origin will be nearly linearly related to the magnetic field in which they are acquired for field strenghts as low as the Earth's. This makes it in principle possible to estimate the strength of ancient magnetic fields. In practice, however, recovering the ancient field strength is complicated. The simple theory only pertains to uniformly magnetized (single domain, SD particles). While SD theory predicts that a magnetization acquired at a temperature T should be demagnetized by zero-field reheating to T, yet failure of this “reciprocity” requirement has long been observed and the causes and consequences for grains with no domain walls are unknown. Recent experiments (Shaar and Tauxe, doi: 10.1073/pnas.1507986112 and Santos and Tauxe, doi:10.1029/2018GC007946) have demonstrated that, in contrast to the stability of SD remanences over time, the remanence in many paleomagnetic samples typically used in paleointensity experiments are unstable, exhibiting an "aging" effect in which the unblocking temperature spectrum changes over only a few years.  This behavior is completely unexpected from theory. Solving these mysteries is key to cracking the problem of paleointensity estimation. In this presentation we will demonstrate that it is a shift in unblocking temperatures observed over even relatively short time intervals (two years) in certain samples that leads to the failure of reciprocity which in turn limits the ability to acquire accurate and precise estimates of the ancient magnetic field. From rock magnetic experiments (xFORCs) it seems likely that magnetic grains larger than the highly stable single vortex state are the source of the non-ideal behavior. This non-ideal behavior which leads to differences between known and estimated fields that can be rather large (up to 10 μT) for individual specimens, does appear to lead to a bias in field estimates.  It is unclear how this behavior can be compensated for using the most common paleointensity estimation methods.   </p>

scholarly journals Observation of Bloch-point domain walls in cylindrical magnetic nanowires

2014 ◽  
Vol 89 (18) ◽  
Author(s):  
S. Da Col ◽  
S. Jamet ◽  
N. Rougemaille ◽  
A. Locatelli ◽  
T. O. Mentes ◽  
...  
Keyword(s):  
Domain Walls ◽  
Magnetic Nanowires
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