Magnetic Behavior of Single Ni Nanowires and its Arrays Embedded in Highly Ordered Nanoporous Alumina Templates

2014 ◽  
Vol 215 ◽  
pp. 298-305 ◽  
Author(s):  
Alexander S. Samardak ◽  
Alexey V. Ognev ◽  
Ekaterina V. Sukovatitsina ◽  
Maxim E. Stebliy ◽  
Evgeny B. Modin ◽  
...  
Keyword(s):  
Magnetization Reversal ◽  
Magnetic Domain ◽  
Magnetic Behavior ◽  
Nanowire Arrays ◽  
Structural Defects ◽  
Domain Pattern ◽  
Magnetostatic Interaction ◽  
Nanoporous Alumina ◽  
Nanoporous Alumina Templates ◽  
Reversal Mechanism

We report on magnetization reversal and geometry dependent magnetic anisotropy of Ni nanowire arrays electrodeposited in nanoporous alumina templates. Using micromagnetic simulation we have found that magnetization reversal mechanism in arrays with different nanowire diameters is curling. This magnetic behavior appears with propagation of the domain wall along a nanowire. The calculations have been proven by the analysis of hysteresis curves. To explain magnetic properties of closely-spaced nanowire arrays we have taken into consideration the magnetostatic interaction between adjacent nanowires and their structural defects, like as boundary grains. The investigated magnetic domain pattern of individual bended nanowires confirms rather complicated magnetization reversal mechanism than either coherent rotation of magnetization or its curling. Competition between the shape and magnetoelastic anisotropies can induce an unusual zigzag-like domain pattern in a single nanowire.

scholarly journals Two-Step Magnetization Reversal FORC Fingerprint of Coupled Bi-Segmented Ni/Co Magnetic Nanowire Arrays

Nanomaterials ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 548 ◽  
Author(s):  
Javier García Fernández ◽  
Víctor Vega Martínez ◽  
Andy Thomas ◽  
Víctor de la Prida Pidal ◽  
Kornelius Nielsch
Keyword(s):  
Magnetization Reversal ◽  
Nanowire Array ◽  
Magnetic Domain ◽  
Magnetic Behavior ◽  
Relative Difference ◽  
Nanowire Arrays ◽  
Magnetic Interactions ◽  
Magnetic Configuration ◽  
Reversal Process ◽  
Magnetization Reversal Process

First Order Reversal Curve (FORC) analysis has been established as an appropriate method to investigate the magnetic interactions among complex ferromagnetic nanostructures. In this work, the magnetization reversal mechanism of bi-segmented nanowires composed by long Co and Ni segments contacted at one side was investigated, as a model system to identify and understand the FORC fingerprint of a two-step magnetization reversal process. The resulting hysteresis loop of the bi-segmented nanowire array exhibits a completely different magnetic behavior than the one expected for the magnetization reversal process corresponding to each respective Co and Ni nanowire arrays, individually. Based on the FORC analysis, two possible magnetization reversal processes can be distinguished as a consequence of the ferromagnetic coupling at the interface between the Ni and Co segments. Depending on the relative difference between the magnetization switching fields of each segment, the softer magnetic phase induces the switching of the harder one through the injection and propagation of a magnetic domain wall when both switching fields are comparable. On the other hand, if the switching fields values differ enough, the antiparallel magnetic configuration of nanowires is also possible but energetically unfavorable, thus resulting in an unstable magnetic configuration. Making use of the different temperature dependence of the magnetic properties for each nanowire segment with different composition, one of the two types of magnetization reversal is favored, as demonstrated by FORC analyses.

Remanence Properties and Magnetization Reversal Mechanism of Fe Nanowire Arrays

2004 ◽  
Vol 21 (5) ◽  
pp. 945-948 ◽  
Author(s):  
Wang Jian-Bo ◽  
Liu Qing-Fang ◽  
Xue De-Sheng ◽  
Li Fa-Shen
Keyword(s):  
Magnetization Reversal ◽  
Nanowire Arrays ◽  
Reversal Mechanism

Magnetization Reversal Mechanism in FeCoNiB Nanowire Arrays

2013 ◽  
Vol 11 (1) ◽  
pp. 131-133
Author(s):  
Malini Vieyra ◽  
Turgut Meydan
Keyword(s):  
Magnetization Reversal ◽  
Nanowire Arrays ◽  
Reversal Mechanism

Magnetization Reversal in Ferromagnetic Thin Films

2011 ◽  
Vol 399-401 ◽  
pp. 890-895
Author(s):  
Jia Li Sun ◽  
Jing Guo Hu
Keyword(s):  
Magnetic Anisotropy ◽  
Magnetization Reversal ◽  
Domain Walls ◽  
Magnetic Domain ◽  
Ferromagnetic Film ◽  
Magnetic Films ◽  
Ferromagnetic Thin Films ◽  
Interface Coupling ◽  
Domain Structures ◽  
Reversal Mechanism

The magnetization reversal mechanism of the magnetic films system with the different magnetic anisotropy, exchange coupling, interface coupling, etc. has been simulated by Monte-Carlo method. The results show that the decrease of magnetic anisotropy is in favor of motion of domain walls, but is not conducive to consistent rotation. The interface coupling of both the ferromagnetic film and the antiferromagnetic film are helpful to the motion of domain walls while the antiferromagnetic film coupling is the more effective. Meantime, the evolution of the microscopic magnetic domain structures has been inspected intuitively while the system is in the process of magnetization.

High density group IV semiconductor nanowire arrays fabricated in nanoporous alumina templates

2005 ◽  
Author(s):  
Joan M. Redwing ◽  
Sarah M. Dilts ◽  
Kok-Keong Lew ◽  
Alexana E. Cranmer ◽  
Suzanne E. Mohney
Keyword(s):  
Group Iv ◽  
High Density ◽  
Nanowire Arrays ◽  
Semiconductor Nanowire ◽  
Nanoporous Alumina ◽  
Group Iv Semiconductor ◽  
Nanoporous Alumina Templates

scholarly journals Single Diameter Modulation Effects on Ni Nanowire Array Magnetization Reversal

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3403
Author(s):  
Luis C. C. Arzuza ◽  
Victor Vega ◽  
Victor M. Prida ◽  
Karoline O. Moura ◽  
Kleber R. Pirota ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Domain Wall ◽  
Long Range ◽  
Magnetization Reversal ◽  
Nanowire Array ◽  
Magnetic Behavior ◽  
Nanowire Arrays ◽  
Magnetic Nanowires ◽  
Range Interaction ◽  
Domain Wall Propagation

Geometrically modulated magnetic nanowires are a simple yet efficient strategy to modify the magnetic domain wall propagation since a simple diameter modulation can achieve its pinning during the nanowire magnetization reversal. However, in dense systems of parallel nanowires, the stray fields arising at the diameter interface can interfere with the domain wall propagation in the neighboring nanowires. Therefore, the magnetic behavior of diameter-modulated nanowire arrays can be quite complex and depending on both short and long-range interaction fields, as well as the nanowire geometric dimensions. We applied the first-order reversal curve (FORC) method to bi-segmented Ni nanowire arrays varying the wide segment (45–65 nm diameter, 2.5–10.0 μm length). The FORC results indicate a magnetic behavior modification depending on its length/diameter aspect ratio. The distributions either exhibit a strong extension along the coercivity axis or a main distribution finishing by a fork feature, whereas the extension greatly reduces in amplitude. With the help of micromagnetic simulations, we propose that a low aspect ratio stabilizes pinned domain walls at the diameter modulation during the magnetization reversal. In this case, long-range axial interaction fields nucleate a domain wall at the nanowire extremities, while short-range ones could induce a nucleation at the diameter interface. However, regardless of the wide segment aspect ratio, the magnetization reversal is governed by the local radial stray fields of the modulation near null magnetization. Our findings demonstrate the capacity of distinguishing between complex magnetic behaviors involving convoluted interaction fields.

Effect of Barrier Layer on Fabrication of FePt Nanowires by Electrodeposition into Nanoporous Alumina Templates

2013 ◽  
Vol 829 ◽  
pp. 707-711
Author(s):  
Ali Fardi Ilkhchy ◽  
Farzad Nasirpouri
Keyword(s):  
Barrier Layer ◽  
Electrochemical Impedance ◽  
Equivalent Circuit Model ◽  
Open Circuit ◽  
Nanowire Arrays ◽  
Nanoporous Structure ◽  
Alumina Membrane ◽  
Electrical Insulator ◽  
Nanoporous Alumina ◽  
Nanoporous Alumina Templates

It is well known that the nanoporous aluminum oxide film is an electrical insulator. In addition the homogeneity of electrodeposited nanowire arrays in nanoporous alumina templates increases drastically with the usage of AC electrodeposition in comparison to DC electrodeposition. This is revealing of the effect of dielectric properties of alumina that is used as template for electrodeposition. In this work integrated nanowire arrays of FePt alloys were successfully fabricated by alternating current electrodeposition on nanoporous alumina; also we characterize the nanoporous alumina membrane that is used as a template for FePt nanowire electrodeposition using EIS allowing the electrochemical impedance contributions from the barrier layer, nanoporous structure, and electrolyte solution resistance to be calculated through the use of an equivalent circuit model. The impedance spectra of the porous film prepared under different anodization conditions were measured. The data is attained at open circuit potential over a frequency range between 1 Hz to 100 KHz with an AC potential amplitude of 10 mV. As our result demonstrates the resistance of the bariyer layer decreases with the anodization temperature then the electrochemical process of FePt nanowires at template which fabricated on low anodization temperature will be difficult due to the higher resistance.

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.

Magnetic Properties of Hexagonally Ordered Arrays of Fe Antidots by Vacuum Thermal Evaporation on Nanoporous Alumina Templates

2009 ◽  
Vol 152-153 ◽  
pp. 273-276 ◽  
Author(s):  
Ricardo López Antón ◽  
Victor Vega ◽  
V.M. Prida ◽  
A. Fernández ◽  
K.R. Pirota ◽  
...  
Keyword(s):  
Magnetic Measurements ◽  
Magnetic Domain ◽  
Film Plane ◽  
Hexagonal Structure ◽  
Easy Magnetization ◽  
Nanoporous Alumina ◽  
Force Microscopy ◽  
Ordered Arrays ◽  
Vapor Deposition Technique ◽  
Nanoporous Alumina Templates

Highly ordered arrays of Fe antidot films were fabricated by thermal vapor deposition technique using nanoporous alumina templates. The film thickness varies from 20 up to 100 nm, and the antidots array has about 50 nm in diameter and 105 nm of periodic interspacing. Scanning electron microscopy and atomic force microscopy measurements confirmed that the Fe antidots film retains the well-ordered hexagonal structure of the nanoporous alumina template. Meanwhile, the micromagnetic structure was studied by magnetic force microscopy and SQUID measurements. A stripe magnetic domain pattern featuring a large out-of-plane magnetization component is found in the films. Noteworthily, the magnetic domains are not pinned by the nanopores but, on the contrary, several antidots are included in each magnetic domain. According to the magnetic measurements, the easy magnetization axis of the Fe antidot array remains in the film plane, while the hard one lies perpendicular to the plane, which can be explained on the basis of the different contributions of the nanoholes to the total magnetic anisotropy of the antidots film.

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