scholarly journals Effect of Sharp Diameter Geometrical Modulation on the Magnetization Reversal of bi-Segmented FeNi Nanowires

2018 ◽  
Author(s):  
Miguel Méndez ◽  
Víctor Vega ◽  
Silvia González ◽  
Rafael Caballero-Flores ◽  
Javier García ◽  
...  
Keyword(s):  
Data Storage ◽  
Magnetization Reversal ◽  
Magnetic Nanostructures ◽  
Magnetic Behavior ◽  
Magnetic Data ◽  
Micromagnetic Simulations ◽  
Precise Control ◽  
Different Types ◽  
Magnetic Decoupling ◽  
Different Diameters

Controlling functional properties of matter and combine them for engineering a functional device is nowadays a common direction of scientific community. For instance, heterogeneous magnetic nanostructures can make use of different types of geometrical and compositional modulations to achieve the control of the magnetization reversal along with the nano-entities and thus enabling the fabrication of spintronic, magnetic data storage and sensing devices, among others. In this work, diameter modulated FeNi nanowires are fabricated paying special effort to obtain sharp transition regions between two segments of different diameters (from about 450 nm to 120 nm), enabling precise control over the magnetic behavior of the sample. Micromagnetic simulations performed on single bi-segmented nanowires predict a double step magnetization reversal where the wide segment magnetization switches near 200 Oe through a vortex domain wall, while at 500 Oe the magnetization of the narrow one is reversed through a corkscrew like mechanism. Finally, these results are confirmed with magneto-optic Kerr effect measurements at the transition of isolated bi-segmented nanowires. Furthermore, macroscopic vibrating sample magnetometry is used to demonstrate that the magnetic decoupling of nanowire segments is the main phenomenon occurring over the entire fabricated nanowires.

scholarly journals Effect of Sharp Diameter Geometrical Modulation on the Magnetization Reversal of Bi-Segmented FeNi Nanowires

Nanomaterials ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 595 ◽  
Author(s):  
Miguel Méndez ◽  
Víctor Vega ◽  
Silvia González ◽  
Rafael Caballero-Flores ◽  
Javier García ◽  
...  
Keyword(s):  
Data Storage ◽  
Magnetization Reversal ◽  
Magnetic Nanostructures ◽  
Magnetic Behavior ◽  
Magnetic Data ◽  
Micromagnetic Simulations ◽  
Precise Control ◽  
Different Types ◽  
Magnetic Decoupling ◽  
Different Diameters

Controlling functional properties of matter and combining them for engineering a functional device is, nowadays, a common direction of the scientific community. For instance, heterogeneous magnetic nanostructures can make use of different types of geometrical and compositional modulations to achieve the control of the magnetization reversal along with the nano-entities and, thus, enable the fabrication of spintronic, magnetic data storage, and sensing devices, among others. In this work, diameter-modulated FeNi nanowires are fabricated paying special effort to obtain sharp transition regions between two segments of different diameters (from about 450 nm to 120 nm), enabling precise control over the magnetic behavior of the sample. Micromagnetic simulations performed on single bi-segmented nanowires predict a double step magnetization reversal where the wide segment magnetization switches near 16 kA/m through a vortex domain wall, while at 40 kA/m the magnetization of the narrow segment is reversed through a corkscrew-like mechanism. Finally, these results are confirmed with magneto-optic Kerr effect measurements at the transition of isolated bi-segmented nanowires. Furthermore, macroscopic vibrating sample magnetometry is used to demonstrate that the magnetic decoupling of nanowire segments is the main phenomenon occurring over the entire fabricated nanowires.

scholarly journals Magnetic Functionalization of Scanning Probes by Focused Electron Beam Induced Deposition Technology

2021 ◽  
Vol 7 (10) ◽  
pp. 140
Author(s):  
Javier Pablo-Navarro ◽  
Soraya Sangiao ◽  
César Magén ◽  
José María de Teresa
Keyword(s):  
Electron Beam ◽  
High Resolution ◽  
Data Storage ◽  
Magnetic Nanostructures ◽  
Magnetic Sensing ◽  
Precise Control ◽  
Scanning Probes ◽  
Different Types ◽  
Electron Beam Induced Deposition ◽  
Deposition Technology

The fabrication of nanostructures with high resolution and precise control of the deposition site makes Focused Electron Beam Induced Deposition (FEBID) a unique nanolithography process. In the case of magnetic materials, apart from the FEBID potential in standard substrates for multiple applications in data storage and logic, the use of this technology for the growth of nanomagnets on different types of scanning probes opens new paths in magnetic sensing, becoming a benchmark for magnetic functionalization. This work reviews the recent advances in the integration of FEBID magnetic nanostructures onto cantilevers to produce advanced magnetic sensing devices with unprecedented performance.

scholarly journals Micromagnetic Simulations of Fe and Ni Nanodot Arrays Surrounded by Magnetic or Non-Magnetic Matrices

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 349
Author(s):  
Devika Sudsom ◽  
Andrea Ehrmann
Keyword(s):  
Magnetic Materials ◽  
Data Storage ◽  
Magnetization Reversal ◽  
Hysteresis Loops ◽  
Object Oriented ◽  
Basic Research ◽  
Memory Systems ◽  
The Other ◽  
Micromagnetic Simulations ◽  
Nanodot Arrays

Combining clusters of magnetic materials with a matrix of other magnetic materials is very interesting for basic research because new, possibly technologically applicable magnetic properties or magnetization reversal processes may be found. Here we report on different arrays combining iron and nickel, for example, by surrounding circular nanodots of one material with a matrix of the other or by combining iron and nickel nanodots in air. Micromagnetic simulations were performed using the OOMMF (Object Oriented MicroMagnetic Framework). Our results show that magnetization reversal processes are strongly influenced by neighboring nanodots and the magnetic matrix by which the nanodots are surrounded, respectively, which becomes macroscopically visible by several steps along the slopes of the hysteresis loops. Such material combinations allow for preparing quaternary memory systems, and are thus highly relevant for applications in data storage and processing.

Graphyne as a promising substrate for high density magnetic storage bits

RSC Advances ◽  
2015 ◽  
Vol 5 (107) ◽  
pp. 87841-87846 ◽  
Author(s):  
Yun Zhang ◽  
Guojun Zhu ◽  
Jinlian Lu ◽  
Zhixin Guo ◽  
Juexian Cao
Keyword(s):  
Data Storage ◽  
Magnetic Nanostructures ◽  
High Density ◽  
Magnetic Data Storage ◽  
Magnetic Data ◽  
Magnetic Storage ◽  
Suitable Substrate

Applying magnetic nanostructures in high density magnetic data storage is hindered by a lack of suitable substrate.

scholarly journals Magnetization Reversal Process and Magnetostatic Interactions in Fe56Co44/SiO2/Fe3O4 Core/Shell Ferromagnetic Nanowires with Non-Magnetic Interlayer

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2282
Author(s):  
Javier García ◽  
Alejandro M. Manterola ◽  
Miguel Méndez ◽  
Jose Angel Fernández-Roldán ◽  
Víctor Vega ◽  
...  
Keyword(s):  
Data Storage ◽  
Magnetization Reversal ◽  
Domain Walls ◽  
Magnetic Domain ◽  
Hysteresis Loops ◽  
Magnetic Data ◽  
Core Shell ◽  
The Core ◽  
Shell Nanostructures ◽  
Magnetostatic Interactions

Nowadays, numerous works regarding nanowires or nanotubes are being published, studying different combinations of materials or geometries with single or multiple layers. However, works, where both nanotube and nanowires are forming complex structures, are scarcer due to the underlying difficulties that their fabrication and characterization entail. Among the specific applications for these nanostructures that can be used in sensing or high-density magnetic data storage devices, there are the fields of photonics or spintronics. To achieve further improvements in these research fields, a complete understanding of the magnetic properties exhibited by these nanostructures is needed, including their magnetization reversal processes and control of the magnetic domain walls. In order to gain a deeper insight into this topic, complex systems are being fabricated by altering their dimensions or composition. In this work, a successful process flow for the additive fabrication of core/shell nanowires arrays is developed. The core/shell nanostructures fabricated here consist of a magnetic nanowire nucleus (Fe56Co44), grown by electrodeposition and coated by a non-magnetic SiO2 layer coaxially surrounded by a magnetic Fe3O4 nanotubular coating both fabricated by means of the Atomic Layer Deposition (ALD) technique. Moreover, the magnetization reversal processes of these coaxial nanostructures and the magnetostatic interactions between the two magnetic components are investigated by means of standard magnetometry and First Order Reversal Curve methodology. From this study, a two-step magnetization reversal of the core/shell bimagnetic nanostructure is inferred, which is also corroborated by the hysteresis loops of individual core/shell nanostructures measured by Kerr effect-based magnetometer.

HR-TEM Studies of FePt Nanoparticles by Exit Wave Reconstruction

2007 ◽  
Vol 998 ◽  
Author(s):  
Daniela Sudfeld ◽  
Olga Dmitrieva ◽  
Nina Friedenberger ◽  
Guenter Dumpich ◽  
Michael Farle ◽  
...  
Keyword(s):  
Data Storage ◽  
Density Functional ◽  
Lattice Structure ◽  
Magnetic Behavior ◽  
Magnetic Data ◽  
Fept Nanoparticles ◽  
Face Centered Cubic ◽  
Scattered Electron ◽  
Transmission Electron ◽  
Face Centered

ABSTRACTFePt nanoparticles are promising materials for high-density magnetic data storage media [1] and bio-medical applications such as drug-targeting and hyperthermia [2]. To understand their magnetic properties [3] it is essential to get insights into the lattice structure of isolated nanoparticles which influence the magnetic behavior.Typically, lattice fringes are observed with high-resolution transmission electron microscopy (HR-TEM). In this case delocalization effects disturb imaging of the lattice structure in particular if 2 to 6 nm small nanoparticles are involved. Therefore, FePt nanocrystals were investigated by reconstructing amplitude and phase of the scattered electron wave from a focal series of HRTEM images, which can produce delocalization free and direct images of the crystal structure [4]. The formation of 5-fold twinned structures of 3 to 7 nm face-centered cubic FePt nanocrystals is investigated that were grown from a colloidal solution [1]. The results are compared with abinitio density functional (DFT) calculations of FePt particles with a diameter of larger than 2 nm. Image simulations were performed with the Accelrys Cerius2 software package (Version 4.6). Good agreement between the ab-initio calculations and the experimental data is found.

scholarly journals Investigation on the Effect of Femtosecond Laser Induced Spin Transfer Torque of GdFeCo Alloy

2021 ◽  
Vol 11 (14) ◽  
pp. 6501
Author(s):  
Haozhe Huang ◽  
Haiwei Wang ◽  
Zhihao Zeng ◽  
Rongyao Wang ◽  
Xinyu Zhang ◽  
...  
Keyword(s):  
Data Storage ◽  
Current Density ◽  
Magnetization Reversal ◽  
Spin Current ◽  
Spin Transfer Torque ◽  
Spin Transfer ◽  
Magnetic Data ◽  
Magnetization Switching ◽  
Switching Speed ◽  
Novel Approach

All-optical magnetic switching (AOS) provides a novel approach to improve writing ability and energy efficiency compared to those utilized in the mainstream magnetic data storage products. Rare earth-transition metals (RE-TM) exhibit extremely fast magnetization switching induced by one single incident linearly polarized laser pulse; however, the mechanism is still ambiguous. Here, we show by atomistic spin simulation that the laser induced spin transfer torque dominates the magnetization reversal of Fe sublattice in Gd25Fe75 alloy, and that the switching speed of Gd25Fe75 alloy is relevant to the amount of spin current. This implies that a possible helicity independent mechanism underlies the RE-TM alloy AOS process. We also find that the greater the spin current density the faster the magnetization switching, and the time magnetization reversal of Gd and Fe takes is also affected by the spin current density.

scholarly journals Micromagnetic study of the vortex state in sub-micron iron discs

2020 ◽  
Vol 233 ◽  
pp. 05002
Author(s):  
Ludgero Peixoto ◽  
C. Sousa ◽  
D. Navas ◽  
J.P. Araújo
Keyword(s):  
Data Storage ◽  
Magnetic Nanostructures ◽  
Hysteresis Loops ◽  
Vortex State ◽  
Magnetic Behaviour ◽  
Micromagnetic Simulations ◽  
Research Fields ◽  
Plane Anisotropy ◽  
The Difference ◽  
The Ideal

Magnetic nanostructures have been widely studied due to its poten¬tial applicability into several research fields such as data storage, sensing and biomedical applications. In this work, micromagnetic simulations (mumax3) of sub-micron iron discs are performed for different normalized inter-dot distance (distance/diameter), to better understand the magnetic behaviour of these nanos-tructures. Two sets of samples were studied: ideal circular discs and disc-shaped nanostructures (based on images of real samples). By analyzing the nucleation and annihilation fields and the magnetic susceptibility, it was found that the (ideal) discs could be considered as isolated for inter-dot distances greater than twice the raidus of the disc (2R). The difference in the shape of the disc-shaped nanostructures resulted in an in-plane anisotropy, noticeable on the hysteresis loops for different directions.

scholarly journals Micromagnetic Simulation of Round Ferromagnetic Nanodots with Varying Roughness and Symmetry

2021 ◽  
Vol 6 (2) ◽  
pp. 19
Author(s):  
Pia Steinmetz ◽  
Andrea Ehrmann
Keyword(s):  
Data Storage ◽  
Magnetization Reversal ◽  
Hysteresis Loops ◽  
Basic Research ◽  
Magnetic Data ◽  
Field Orientation ◽  
Thin Ring ◽  
Production Technologies ◽  
Magnetic States ◽  
The Impact

Magnetic nanodots are of high interest for basic research due to their broad spectrum of possible magnetic states and magnetization reversal processes. Besides, they are of technological interest since they can be applied in magnetic data storage, especially if vortex states occur in closed dots or open rings. While producing such nanorings and nanodots from diverse magnetic materials by lithographic techniques is quite common nowadays, these production technologies are naturally prone to small deviations of the borders of these nanoparticles. Here we investigate the influence of well-defined angular-dependent roughness of the edges, created by building the nanoparticles from small cubes, on the resulting hysteresis loops and magnetization reversal processes in five different round nanodots with varying open areas, from a thin ring to a closed nanodot. By varying the orientation of the external magnetic field, the impact of the angle-dependent roughness can be estimated. Especially for the thinnest ring, significant dependence of the transverse magnetization component on the field orientation can be found.

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