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.

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 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.

Direct observation of dynamical magnetization reversal process governed by shape anisotropy in single NiFe2O4 nanowire

Nanoscale ◽  
2018 ◽  
Vol 10 (21) ◽  
pp. 10123-10129 ◽  
Author(s):  
Junli Zhang ◽  
Shimeng Zhu ◽  
Hongli Li ◽  
Liu Zhu ◽  
Yang Hu ◽  
...  
Keyword(s):  
Direct Observation ◽  
Magnetization Reversal ◽  
Magnetic Behavior ◽  
Shape Anisotropy ◽  
Reversal Process ◽  
Magnetization Reversal Process

Direct observation of dynamical magnetization reversal process in a NiFe2O4 nanowire reveals the domination of shape anisotropy on its magnetic behavior.

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.

scholarly journals Tuning the magnetization reversal process of FeCoCu nanowire arrays by thermal annealing

2013 ◽  
Vol 114 (4) ◽  
pp. 043908 ◽  
Author(s):  
C. Bran ◽  
Yu. P. Ivanov ◽  
J. García ◽  
R. P. del Real ◽  
V. M. Prida ◽  
...  
Keyword(s):  
Thermal Annealing ◽  
Magnetization Reversal ◽  
Nanowire Arrays ◽  
Reversal Process ◽  
Magnetization Reversal Process
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