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.

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.

Metal-insulator Transition and Magnetic Domains in (Ga,Mn)As Epilayers

2006 ◽  
Vol 941 ◽  
Author(s):  
Alexandre Dourlat ◽  
Catherine Gourdon ◽  
Vincent Jeudy ◽  
Frédéric Bernardot ◽  
Christophe Testelin ◽  
...  
Keyword(s):  
Domain Walls ◽  
Magnetic Domain ◽  
Perpendicular Magnetic Anisotropy ◽  
Domain Pattern ◽  
Magnetic Domains ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Large Size ◽  
Strong Pinning ◽  
Pinning Of Domain Walls

ABSTRACTWe investigate the magnetic domain pattern in (Ga,Mn)As epilayers with perpendicular magnetic anisotropy. We show that post-growth annealing, besides improving the magnetic and transport properties, also drastically changes the domain pattern. Strong pinning of domain walls along the <110> directions is suppressed and large-size domains are observed.

Lorentz Microscopy: Effect of Tilting on Magnetic Domains in Single Crystal Iron Films

1968 ◽  
Vol 26 ◽  
pp. 388-389
Author(s):  
L. F. Allard ◽  
A. P. Rowe ◽  
P. L. Fan
Keyword(s):  
Single Crystal ◽  
Domain Walls ◽  
Magnetic Domain ◽  
Objective Lens ◽  
Pole Piece ◽  
Magnetic Domains ◽  
Iron Films ◽  
Lorentz Microscopy ◽  
Magnetic Domain Walls ◽  
Microscopy Techniques

In order to observe magnetic domain walls by Lorentz microscopy techniques it is often necessary either to operate the microscope with the objective lens off, thus severely limiting the magnification, or to move the specimen from its usual position or make some other modification so that the field to which it is subjected is not so strong that it saturates the specimen. However, conditions in the JEM-6A have proved favorable for observation of domains in single crystal iron films by the out-of-focus method without any modifications, using either the regular specimen stage with the small bore pole piece or the tilting stage with the large bore pole piece. The tilting stage is particularly useful for these studies because the domains are very sensitive to small differences in inclination in the field.

scholarly journals Electric-field-driven dynamics of magnetic domain walls in magnetic nanowires patterned on ferroelectric domains

2016 ◽  
Vol 18 (3) ◽  
pp. 033027 ◽  
Author(s):  
Ben Van de Wiele ◽  
Jonathan Leliaert ◽  
Kévin J A Franke ◽  
Sebastiaan van Dijken
Keyword(s):  
Electric Field ◽  
Domain Walls ◽  
Magnetic Domain ◽  
Magnetic Nanowires ◽  
Ferroelectric Domains ◽  
Magnetic Domain Walls

scholarly journals Nanowire spintronics for storage class memories and logic

2011 ◽  
Vol 369 (1948) ◽  
pp. 3214-3228 ◽  
Author(s):  
G. Hrkac ◽  
J. Dean ◽  
D. A. Allwood
Keyword(s):  
Data Storage ◽  
Domain Walls ◽  
Random Access ◽  
Magnetic Nanowires ◽  
Digital Information ◽  
Efficient Operation ◽  
The Future ◽  
Magnetic Nanowire ◽  
Future Direction ◽  
High Level

Patterned magnetic nanowires are extremely well suited for data storage and logic devices. They offer non-volatile storage, fast switching times, efficient operation and a bistable magnetic configuration that are convenient for representing digital information. Key to this is the high level of control that is possible over the position and behaviour of domain walls (DWs) in magnetic nanowires. Magnetic random access memory based on the propagation of DWs in nanowires has been released commercially, while more dynamic shift register memory and logic circuits have been demonstrated. Here, we discuss the present standing of this technology as well as reviewing some of the basic DW effects that have been observed and the underlying physics of DW motion. We also discuss the future direction of magnetic nanowire technology to look at possible developments, hurdles to overcome and what nanowire devices may appear in the future, both in classical information technology and beyond into quantum computation and biology.

scholarly journals Magnetic domains and domain wall pinning in atomically thin CrBr3 revealed by nanoscale imaging

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Qi-Chao Sun ◽  
Tiancheng Song ◽  
Eric Anderson ◽  
Andreas Brunner ◽  
Johannes Förster ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Domain Walls ◽  
Magnetic Domain ◽  
Quantitative Information ◽  
Nitrogen Vacancy ◽  
Two Dimensional ◽  
Magnetic Domains ◽  
Nitrogen Vacancy Center ◽  
The Rich ◽  
Vacancy Center

AbstractThe emergence of atomically thin van der Waals magnets provides a new platform for the studies of two-dimensional magnetism and its applications. However, the widely used measurement methods in recent studies cannot provide quantitative information of the magnetization nor achieve nanoscale spatial resolution. These capabilities are essential to explore the rich properties of magnetic domains and spin textures. Here, we employ cryogenic scanning magnetometry using a single-electron spin of a nitrogen-vacancy center in a diamond probe to unambiguously prove the existence of magnetic domains and study their dynamics in atomically thin CrBr3. By controlling the magnetic domain evolution as a function of magnetic field, we find that the pinning effect is a dominant coercivity mechanism and determine the magnetization of a CrBr3 bilayer to be about 26 Bohr magnetons per square nanometer. The high spatial resolution of this technique enables imaging of magnetic domains and allows to locate the sites of defects that pin the domain walls and nucleate the reverse domains. Our work highlights scanning nitrogen-vacancy center magnetometry as a quantitative probe to explore nanoscale features in two-dimensional magnets.

Influence of Magnetic Domain Walls and Magnetic Field on the Thermal Conductivity of Magnetic Nanowires

Nano Letters ◽  
2015 ◽  
Vol 15 (5) ◽  
pp. 2773-2779 ◽  
Author(s):  
Hao-Ting Huang ◽  
Mei-Feng Lai ◽  
Yun-Fang Hou ◽  
Zung-Hang Wei
Keyword(s):  
Magnetic Field ◽  
Thermal Conductivity ◽  
Domain Walls ◽  
Magnetic Domain ◽  
Magnetic Nanowires ◽  
Magnetic Domain Walls

Microstructure and Magnetic Domain Wall Motion

1981 ◽  
Vol 39 ◽  
pp. 324-325
Author(s):  
I. N. Lin
Keyword(s):  
Domain Walls ◽  
Ion Beam ◽  
Magnetic Loss ◽  
Magnetic Domain ◽  
Domain Wall Motion ◽  
Soft Magnetic Materials ◽  
Magnetic Domains ◽  
Materials Used ◽  
Mnzn Ferrites

MnZn-ferrites and Li-ferrites are soft magnetic materials used in telecommunication and entertainment electronics because of their high magnetic permeability and low magnetic loss characteristics. The magnetic properties of these materials are very sensitive to composition and microstructure. In the present paper, results of an investigation of the interaction of magnetic domains with the microstructural features are presented and the significance of such studied on microstructure-property relationships is discussed.Lorentz microscopic technique in TEM has been used to study the domain wal structure and its interaction with grain boundaries, precipitates, pores, cracks, etc. in situ. Electron transparent specimens from bulk samples were prepared by ion beam milling technique and were examined in a Philips EM301 microscope operating at 100kV. The motion of domain walls was studied in situ by tilting the specimen so that there is a magnetic field applied to the plane of the specimen.

scholarly journals Narrow Segment Driven Multistep Magnetization Reversal Process in Sharp Diameter Modulated Fe67Co33 Nanowires

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3077
Author(s):  
Javier García ◽  
Jose A. Fernández-Roldán ◽  
Roque González ◽  
Miguel Méndez ◽  
Cristina Bran ◽  
...  
Keyword(s):  
Data Storage ◽  
Magnetization Reversal ◽  
Domain Walls ◽  
Nanowire Array ◽  
Magnetic Hysteresis ◽  
Magnetic Domain ◽  
Hysteresis Loops ◽  
Magnetic Behavior ◽  
Magnetic Nanomaterials ◽  
Magnetic Nanowires

Magnetic nanomaterials are of great interest due to their potential use in data storage, biotechnology, or spintronic based devices, among others. The control of magnetism at such scale entails complexing the nanostructures by tuning their composition, shape, sizes, or even several of these properties at the same time, in order to search for new phenomena or optimize their performance. An interesting pathway to affect the dynamics of the magnetization reversal in ferromagnetic nanostructures is to introduce geometrical modulations to act as nucleation or pinning centers for the magnetic domain walls. Considering the case of 3D magnetic nanowires, the modulation of the diameter across their length can produce such effect as long as the segment diameter transition is sharp enough. In this work, diameter modulated Fe67Co33 ferromagnetic nanowires have been grown into the prepatterned diameter modulated nanopores of anodized Al2O3 membranes. Their morphological and compositional characterization was carried out by electron-based microscopy, while their magnetic behavior has been measured on both the nanowire array as well as for individual bisegmented nanowires after being released from the alumina template. The magnetic hysteresis loops, together with the evaluation of First Order Reversal Curve diagrams, point out that the magnetization reversal of the bisegmented FeCo nanowires is carried out in two steps. These two stages are interpreted by micromagnetic modeling, where a shell of the wide segment reverses its magnetization first, followed by the reversal of its core together with the narrow segment of the nanowire at once.

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.

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