scholarly journals Reversible switching of magnetic states by electric fields in nitrogenized-divacancies graphene decorated by tungsten atoms

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Gui-Xian Ge ◽  
Hai-Bin Sun ◽  
Yan Han ◽  
Feng-Qi Song ◽  
Ji-Jun Zhao ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Data Storage ◽  
Electric Fields ◽  
High Performance ◽  
Occupation Number ◽  
Magnetic Storage ◽  
Magnetic Anisotropy Energy ◽  
Magnetic States ◽  
Storage Units ◽  
Promising Avenue

Abstract Magnetic graphene-based materials have shown great potential for developing high-performance electronic devices at sub-nanometer such as spintronic data storage units. However, a significant reduction of power consumption and great improvement of structural stability are needed before they can be used for actual applications. Based on the first-principles calculations, here we demonstrate that the interaction between tungsten atoms and nitrogenized-divacancies (NDVs) in the hybrid W@NDV-graphene can lead to high stability and large magnetic anisotropy energy (MAE). More importantly, reversible switching between different magnetic states can be implemented by tuning the MAE under different electric fields and very low energy is consumed during the switching. Such controllable switching of magnetic states is ascribed to the competition between the tensile stain and orbital magnetic anisotropy, which originates from the change in the occupation number of W-5d orbitals under the electric fields. Our results provide a promising avenue for developing high-density magnetic storage units or multi-state logical switching devices with ultralow power at sub-nanometer.

scholarly journals Magnetic anisotropy of graphene quantum dots decorated with a ruthenium adatom

2013 ◽  
Vol 4 ◽  
pp. 441-445 ◽  
Author(s):  
Igor Beljakov ◽  
Velimir Meded ◽  
Franz Symalla ◽  
Karin Fink ◽  
Sam Shallcross ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Density Functional ◽  
Magnetic Transition ◽  
Graphene Quantum Dots ◽  
Magnetic Storage ◽  
Magnetic Anisotropy Energy ◽  
Magnetization Direction ◽  
Storage Devices ◽  
Out Of Plane ◽  
Graphene Edge

The creation of magnetic storage devices by decoration of a graphene sheet by magnetic transition-metal adatoms, utilizing the high in-plane versus out-of-plane magnetic anisotropy energy (MAE), has recently been proposed. This concept is extended in our density-functional-based modeling study by incorporating the influence of the graphene edge on the MAE. We consider triangular graphene flakes with both armchair and zigzag edges in which a single ruthenium adatom is placed at symmetrically inequivalent positions. Depending on the edge-type, the graphene edge was found to influence the MAE in opposite ways: for the armchair flake the MAE increases close to the edge, while the opposite is true for the zigzag edge. Additionally, in-plane pinning of the magnetization direction perpendicular to the edge itself is observed for the first time.

Uniaxial magnetic anisotropy energy of bimetallic Co–Ni clusters from a first-principles perspective

2018 ◽  
Vol 20 (24) ◽  
pp. 16528-16539 ◽  
Author(s):  
J. Mejía-López ◽  
Ana Mejía-López ◽  
J. Mazo-Zuluaga
Keyword(s):  
Magnetic Anisotropy ◽  
First Principles ◽  
Molecular Magnetism ◽  
Magnetic Storage ◽  
Chemical Behavior ◽  
Magnetic Anisotropy Energy ◽  
Uniaxial Magnetic Anisotropy ◽  
Physical Chemical ◽  
New Information ◽  
Ni Clusters

New information regarding the magnetic anisotropy and physical–chemical behavior of CoNi nanoclusters makes them promising for magnetic-storage, molecular-magnetism or quantum-computation.

Electric field control of the magnetic anisotropy energy of double-vacancy graphene decorated by iridium atoms

2016 ◽  
Vol 18 (16) ◽  
pp. 11550-11555 ◽  
Author(s):  
Gui-Xian Ge ◽  
Ying-Bin Li ◽  
Guang-Hou Wang ◽  
Jian-Guo Wan
Keyword(s):  
Electric Field ◽  
Magnetic Anisotropy ◽  
Electric Fields ◽  
Anisotropy Energy ◽  
Magnetic Anisotropy Energy ◽  
Field Control

The system of Ir@DV possesses large MAE and the amplitude of MAE can be easily manipulated by electric fields.

scholarly journals Barium hexaferrite/muscovite heteroepitaxy with mechanically robust perpendicular magnetic anisotropy

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Wei-En Ke ◽  
Pao-Wen Shao ◽  
Chang-Yang Kuo ◽  
Haili Song ◽  
Rong Huang ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Perpendicular Magnetic Anisotropy ◽  
Barium Hexaferrite ◽  
Magnetic Storage ◽  
Circuit Boards ◽  
Magnetic Anisotropy Energy ◽  
Storage Devices ◽  
Magnetic Devices ◽  
Mechanical Bending ◽  
Magnetic Storage Devices

AbstractRecent advances in the design and development of magnetic storage devices have led to an enormous interest in materials with perpendicular magnetic anisotropy (PMA) property. The past decade has witnessed a huge growth in the development of flexible devices such as displays, circuit boards, batteries, memories, etc. since they have gradually made an impact on people’s lives. Thus, the integration of PMA materials with flexible substrates can benefit the development of flexible magnetic devices. In this study, we developed a heteroepitaxy of BaFe12O19 (BaM)/muscovite which displays both mechanical flexibility and PMA property. The particular PMA property was characterized by vibrating sample magnetometer, magnetic force microscopy, and x-ray absorption spectroscopy. To quantify the PMA property of the system, the intrinsic magnetic anisotropy energy density of ~2.83 Merg cm−3 was obtained. Furthermore, the heterostructure exhibits robust PMA property against severe mechanical bending. The findings of this study on the BaM/muscovite heteroepitaxy have several important implications for research in next-generation flexible magnetic recording devices and actuators.

scholarly journals Materials for Magnetic Data Storage: The Ongoing Quest for Superior Magnetic Materials

MRS Bulletin ◽  
2006 ◽  
Vol 31 (5) ◽  
pp. 374-378 ◽  
Author(s):  
Hans Coufal ◽  
Lisa Dhar ◽  
C. Denis Mee
Keyword(s):  
Magnetic Materials ◽  
Data Storage ◽  
Magnetic Recording ◽  
Magnetic Tape ◽  
High Performance ◽  
Materials Science ◽  
Disk Drive ◽  
Magnetic Data Storage ◽  
Magnetic Data ◽  
Magnetic Storage

AbstractFrom its inception until today, and for the foreseeable future, magnetic data storage on disks and tape has provided constantly increased storage density.This has required not only constant innovation, but also major breakthroughs in magnetic materials, both for the media and the read head. Today's disk and tape drives take advantage of novel nanoengineered composite magnetic materials and quantum mechanical processes.In this issue of MRS Bulletin, we present a number of review articles by some of the leaders in this rapidly moving field that highlight the key materials science accomplishments that have enabled the tremendous progress in hard disk drive and magnetic tape technologies.Individual articles describe the materials involved in state-of-the-art magnetic recording, advanced media for perpendicular magnetic recording, the materials challenges of achieving high performance in flexible media such as magnetic tape, the materials issues of read heads, and future avenues for magnetic storage beyond magnetic recording, such as nanowires and spintronics.

Magnetization dynamics of irradiation-fabricated perpendicularly magnetized dots inside a softer magnetic matrix

2003 ◽  
Vol 777 ◽  
Author(s):  
T. Devolder ◽  
M. Belmeguenai ◽  
C. Chappert ◽  
H. Bernas ◽  
Y. Suzuki
Keyword(s):  
Domain Wall ◽  
Magnetic Anisotropy ◽  
Magnetization Reversal ◽  
Ion Irradiation ◽  
Magnetic Nanostructures ◽  
Magnetic Storage ◽  
Exchange Field ◽  
Static Magnetization ◽  
Specific Domain ◽  
Helium Ion

AbstractGlobal Helium ion irradiation can tune the magnetic properties of thin films, notably their magneto-crystalline anisotropy. Helium ion irradiation through nanofabricated masks can been used to produce sub-micron planar magnetic nanostructures of various types. Among these, perpendicularly magnetized dots in a matrix of weaker magnetic anisotropy are of special interest because their quasi-static magnetization reversal is nucleation-free and proceeds by a very specific domain wall injection from the magnetically “soft” matrix, which acts as a domain wall reservoir for the “hard” dot. This guarantees a remarkably weak coercivity dispersion. This new type of irradiation-fabricated magnetic device can also be designed to achieve high magnetic switching speeds, typically below 100 ps at a moderate applied field cost. The speed is obtained through the use of a very high effective magnetic field, and high resulting precession frequencies. During magnetization reversal, the effective field incorporates a significant exchange field, storing energy in the form of a domain wall surrounding a high magnetic anisotropy nanostructure's region of interest. The exchange field accelerates the reversal and lowers the cost in reversal field. Promising applications to magnetic storage are anticipated.

scholarly journals Intrinsically weak magnetic anisotropy of cerium in potential hard-magnetic intermetallics

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Anna Galler ◽  
Semih Ener ◽  
Fernando Maccari ◽  
Imants Dirba ◽  
Konstantin P. Skokov ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Magnetic Anisotropy ◽  
High Performance ◽  
Kondo Effect ◽  
Quantitative Description ◽  
Many Body ◽  
Heavy Rare Earth Elements ◽  
Fe Intermetallics ◽  
Full Temperature

AbstractCerium-based intermetallics are currently attracting much interest as a possible alternative to existing high-performance magnets containing scarce heavy rare-earth elements. However, the intrinsic magnetic properties of Ce in these systems are poorly understood due to the difficulty of a quantitative description of the Kondo effect, a many-body phenomenon where conduction electrons screen out the Ce-4f moment. Here, we show that the Ce-4f shell in Ce–Fe intermetallics is partially Kondo screened. The Kondo scale is dramatically enhanced by nitrogen interstitials suppressing the Ce-4f contribution to the magnetic anisotropy, in striking contrast to the effect of nitrogenation in isostructural intermetallics containing other rare-earth elements. We determine the full temperature dependence of the Ce-4f single-ion anisotropy and show that even unscreened Ce-4f moments contribute little to the room-temperature intrinsic magnetic hardness. Our study thus establishes fundamental constraints on the potential of cerium-based permanent magnet intermetallics.

scholarly journals Ultrafast optical manipulation of magnetic order in ferromagnetic materials

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Chuangtang Wang ◽  
Yongmin Liu
Keyword(s):  
Data Storage ◽  
Optical Switching ◽  
Ultrafast Lasers ◽  
Transport Model ◽  
Magnetic Interaction ◽  
Ferromagnetic Materials ◽  
Magnetic Storage ◽  
Magnetization Dynamics ◽  
Quarter Century ◽  
Ultrafast Optical

Abstract The interaction between ultrafast lasers and magnetic materials is an appealing topic. It not only involves interesting fundamental questions that remain inconclusive and hence need further investigation, but also has the potential to revolutionize data storage technologies because such an opto-magnetic interaction provides an ultrafast and energy-efficient means to control magnetization. Fruitful progress has been made in this area over the past quarter century. In this paper, we review the state-of-the-art experimental and theoretical studies on magnetization dynamics and switching in ferromagnetic materials that are induced by ultrafast lasers. We start by describing the physical mechanisms of ultrafast demagnetization based on different experimental observations and theoretical methods. Both the spin-flip scattering theory and the superdiffusive spin transport model will be discussed in detail. Then, we will discuss laser-induced torques and resultant magnetization dynamics in ferromagnetic materials. Recent developments of all-optical switching (AOS) of ferromagnetic materials towards ultrafast magnetic storage and memory will also be reviewed, followed by the perspectives on the challenges and future directions in this emerging area.

scholarly journals Nonvolatile Ternary Resistive Memory Performance of a Benzothiadiazole-Based Donor–Acceptor Material on ITO-Coated Glass

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 318
Author(s):  
Yang Li ◽  
Cheng Zhang ◽  
Zhiming Shi ◽  
Jingni Li ◽  
Qingyun Qian ◽  
...  
Keyword(s):  
Data Storage ◽  
High Performance ◽  
Memory Performance ◽  
Resistive Memory ◽  
Molecular Systems ◽  
Threshold Voltages ◽  
Donor Acceptor ◽  
Low Threshold ◽  
Multilevel Memory ◽  
Further Development

The explosive growth of data and information has increasingly motivated scientific and technological endeavors toward ultra-high-density data storage (UHDDS) applications. Herein, a donor−acceptor (D–A) type small conjugated molecule containing benzothiadiazole (BT) is prepared (NIBTCN), which demonstrates multilevel resistive memory behavior and holds considerable promise for implementing the target of UHDDS. The as-prepared device presents distinct current ratios of 105.2/103.2/1, low threshold voltages of −1.90 V and −3.85 V, and satisfactory reproducibility beyond 60%, which suggests reliable device performance. This work represents a favorable step toward further development of highly-efficient D−A molecular systems, which opens more opportunities for achieving high performance multilevel memory materials and devices.

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