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

Imaging of ferroelectric domain walls by electron holography

1992 ◽  
Vol 50 (1) ◽  
pp. 246-247
Author(s):  
Xiao Zhang
Keyword(s):  
Magnetic Field ◽  
High Resolution ◽  
Domain Walls ◽  
Ferroelectric Domain ◽  
Object Wave ◽  
Electron Holography ◽  
High Resolution Imaging ◽  
Quantitative Measurements ◽  
Resolution Imaging ◽  
Electron Microscopes

Electron holography has recently been available to modern electron microscopy labs with the development of field emission electron microscopes. The unique advantage of recording both amplitude and phase of the object wave makes electron holography a effective tool to study electron optical phase objects. The visibility of the phase shifts of the object wave makes it possible to directly image the distributions of an electric or a magnetic field at high resolution. This work presents preliminary results of first high resolution imaging of ferroelectric domain walls by electron holography in BaTiO3 and quantitative measurements of electrostatic field distribution across domain walls.

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 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.

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.

Flux Quantization in Magnetic Nanowires Imaged by Electron Holography

1995 ◽  
Vol 75 (25) ◽  
pp. 4630-4633 ◽  
Author(s):  
Conradin Beeli ◽  
Bernard Doudin ◽  
Pierre Stadelmann
Keyword(s):  
Electron Holography ◽  
Magnetic Nanowires ◽  
Flux Quantization

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.

Application of electron holography to ferroelectric study

1993 ◽  
Vol 51 ◽  
pp. 1092-1093
Author(s):  
X. Zhang ◽  
D. C. Joy ◽  
L. F. Allard ◽  
T. A. Nolan
Keyword(s):  
Domain Wall ◽  
Domain Walls ◽  
Ferroelectric Domain ◽  
Electron Holography ◽  
Local Domain ◽  
Holographic Method ◽  
Wall Area ◽  
Weak Phase ◽  
Wall Structures ◽  
Essential Input

With the development of FE TEM, electron holography becomes a reality to materials scientists, which opens a new window for materials study. Weak phase objects, such as a thin transparent specimen or an electric or a magnetic field, which have little or no effect on the intensity of the transmitted wave, can readily be observed via holography because of the phase shift that they produce. Application of the electron holographic method has been extended to the study of ferroelectric domain wall structures. This work presents the most recent results in this area.Polarization gradients within domain walls are extremely important for the understanding of the extrinsic elastio-dielectric properties of ferroelectrics. Electron holographic studies of the local domain wall profiles provide essential input parameters for phenomenological theories of domain structure and of the macroscopic properties derived from the theories. Figure 1(a) is an electron hologram of the ferroelectric (BaTiO3) 90° domain wall area.

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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