scholarly journals Correction to “In-Plane Magnetic Domains and Néel-Like Domain Walls in Thin Flakes of the Room Temperature CrTe2 Van der Waals Ferromagnet”

2021 ◽  
Author(s):  
Anike Purbawati ◽  
Johann Coraux ◽  
Jan Vogel ◽  
Abdellali Hadj-Azzem ◽  
NianJheng Wu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Domain Walls ◽  
Van Der Waals ◽  
Magnetic Domains

scholarly journals In-Plane Magnetic Domains and Néel-like Domain Walls in Thin Flakes of the Room Temperature CrTe2 Van der Waals Ferromagnet

2020 ◽  
Vol 12 (27) ◽  
pp. 30702-30710 ◽  
Author(s):  
Anike Purbawati ◽  
Johann Coraux ◽  
Jan Vogel ◽  
Abdellali Hadj-Azzem ◽  
NianJheng Wu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Domain Walls ◽  
Van Der Waals ◽  
Magnetic Domains

scholarly journals Ultrafast current and field driven domain-wall dynamics in van der Waals antiferromagnet MnPS3

2020 ◽  
Author(s):  
Ignacio Alliati ◽  
Richard Evans ◽  
Kostya Novoselov ◽  
Elton Santos
Keyword(s):  
Magnetic Fields ◽  
Domain Wall ◽  
Domain Walls ◽  
Van Der Waals ◽  
Honeycomb Structure ◽  
Magnetic Domains ◽  
Electric Currents ◽  
Functional Feature ◽  
Additional Degree ◽  
Domain Wall Dynamics

Abstract The discovery of magnetism in two-dimensional (2D) van der Waals (vdW) materials1–4 has flourished a new endeavour of fundamental problems in magnetism as well as potential applications in computing, sensing and storage technologies5–10. Of particular interest are antiferromagnets 11, 12, which due to their intrinsic antiferromagnetic exchange coupling show several advantages in relation to ferromagnets such as robustness against external magnetic perturbations. This property is one of the cornerstones of antiferromagnets13 and implies that in formation stored in antiferromagnetic domains is invisible to applied magnetic fields preventing it from being erased or manipulated. Here we show that, despite this fundamental understanding, the magnetic domains of recently discovered 2D vdW MnPS3 antiferromagnet14, 15 can be controlled via external magnetic fields and electric currents. We realize ultrafast domain-wall dynamics with velocities up to ∼1500 m s−1 and ∼3000 m s−1 respectively to a broad range of field magnitudes (0.0001−22 T) and current densities (108 − 1010 A cm−2). Both domain wall dynamics are determined by the edge terminations which generated uncompensated spins following the underlying symmetry of the honeycomb structure. We find that edge atoms belonging to different magnetic sublattices function as geometrical constrictions preventing the displacement of the wall, whereas having atoms of the same sublattice at both edges of the material allows for the field-driven domain wall motion which is only limited by the spin-flop transition of the antiferromagnet beyond 25 T. Conversely, electric currents can induce motion of domain walls in most of the edges except those where the two sublattices are present at the borders (e.g. armchair edges). Furthermore, the orientation of the layer relative to the current flow provides an additional degree of freedom for controlling and manipulating magnetic domains in MnPS3. Our results indicate that the implementation of 2D vdW antiferromagnets in real applications requires the engineering of the layer edges which enables an unprecedented functional feature in ultrathin device platforms.

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.

scholarly journals Mid infrared polarization engineering via sub-wavelength biaxial hyperbolic van der Waals crystals

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Saurabh Dixit ◽  
Nihar Ranjan Sahoo ◽  
Abhishek Mall ◽  
Anshuman Kumar
Keyword(s):  
Room Temperature ◽  
Extinction Ratio ◽  
Polarization State ◽  
Van Der Waals ◽  
Photonic Devices ◽  
Mid Infrared ◽  
Precise Control ◽  
Electromagnetic Simulations ◽  
Frequency Regime ◽  
Sub Wavelength

AbstractMid-infrared (IR) spectral region is of immense importance for astronomy, medical diagnosis, security and imaging due to the existence of the vibrational modes of many important molecules in this spectral range. Therefore, there is a particular interest in miniaturization and integration of IR optical components. To this end, 2D van der Waals (vdW) crystals have shown great potential owing to their ease of integration with other optoelectronic platforms and room temperature operation. Recently, 2D vdW crystals of $$\alpha$$ α -$$\hbox {MoO}_{3}$$ MoO 3 and $$\alpha$$ α -$$\hbox {V}_2 \hbox {O}_5$$ V 2 O 5 have been shown to possess the unique phenomenon of natural in-plane biaxial hyperbolicity in the mid-infrared frequency regime at room temperature. Here, we report a unique application of this in-plane hyperbolicity for designing highly efficient, lithography free and extremely subwavelength mid-IR photonic devices for polarization engineering. In particular, we show the possibility of a significant reduction in the device footprint while maintaining an enormous extinction ratio from $$\alpha$$ α -$$\hbox {MoO}_{3}$$ MoO 3 and $$\alpha$$ α -$$\hbox {V}_2$$ V 2 $$\hbox {O}_5$$ O 5 based mid-IR polarizers. Furthermore, we investigate the application of sub-wavelength thin films of these vdW crystals towards engineering the polarization state of incident mid-IR light via precise control of polarization rotation, ellipticity and relative phase. We explain our results using natural in-plane hyperbolic anisotropy of $$\alpha$$ α -$$\hbox {MoO}_{3}$$ MoO 3 and $$\alpha$$ α -$$\hbox {V}_2$$ V 2 $$\hbox {O}_5$$ O 5 via both analytical and full-wave electromagnetic simulations. This work provides a lithography free alternative for miniaturized mid-infrared photonic devices using the hyperbolic anisotropy of $$\alpha$$ α -$$\hbox {MoO}_{3}$$ MoO 3 and $$\alpha$$ α -$$\hbox {V}_2$$ V 2 $$\hbox {O}_5$$ O 5 .

scholarly journals Room Temperature Electroluminescence from Mechanically Formed van der Waals III-VI Homojunctions and Heterojunctions

2014 ◽  
Vol 2 (11) ◽  
pp. 1064-1069 ◽  
Author(s):  
Nilanthy Balakrishnan ◽  
Zakhar R. Kudrynskyi ◽  
Michael W. Fay ◽  
Garry W. Mudd ◽  
Simon A. Svatek ◽  
...  
Keyword(s):  
Room Temperature ◽  
Van Der Waals

Fabrication and magnetic-electronic properties of van der Waals Cr4Te5 ferromagnetic film

CrystEngComm ◽  
2021 ◽  
Author(s):  
Weiyuan Wang ◽  
Jiyu Fan ◽  
Hao Liu ◽  
Huan Zheng ◽  
Chuanlan Ma ◽  
...  
Keyword(s):  
Electronic Properties ◽  
Room Temperature ◽  
Van Der Waals ◽  
Ferromagnetic Film ◽  
Ferromagnetic Materials ◽  
Two Dimensional ◽  
Actual Number ◽  
Intrinsic Ferromagnetism

Exploiting two-dimensional room temperature ferromagnetic materials is always a significant and valuable work. However, the actual number of satisfied materials with intrinsic ferromagnetism is very limited. Here, the van der...

scholarly journals Ultrafast manipulation of mirror domain walls in a charge density wave

2018 ◽  
Vol 4 (10) ◽  
pp. eaau5501 ◽  
Author(s):  
Alfred Zong ◽  
Xiaozhe Shen ◽  
Anshul Kogar ◽  
Linda Ye ◽  
Carolyn Marks ◽  
...  
Keyword(s):  
Charge Density ◽  
Charge Density Wave ◽  
Room Temperature ◽  
Domain Walls ◽  
Density Wave ◽  
Charge Ordering ◽  
Time Resolved ◽  
Insulator Metal Transition ◽  
Femtosecond Light Pulse ◽  
A Charge

Domain walls (DWs) are singularities in an ordered medium that often host exotic phenomena such as charge ordering, insulator-metal transition, or superconductivity. The ability to locally write and erase DWs is highly desirable, as it allows one to design material functionality by patterning DWs in specific configurations. We demonstrate such capability at room temperature in a charge density wave (CDW), a macroscopic condensate of electrons and phonons, in ultrathin 1T-TaS2. A single femtosecond light pulse is shown to locally inject or remove mirror DWs in the CDW condensate, with probabilities tunable by pulse energy and temperature. Using time-resolved electron diffraction, we are able to simultaneously track anti-synchronized CDW amplitude oscillations from both the lattice and the condensate, where photoinjected DWs lead to a red-shifted frequency. Our demonstration of reversible DW manipulation may pave new ways for engineering correlated material systems with light.

scholarly journals Strong intrinsic room-temperature ferromagnetism in freestanding non-van der Waals ultrathin 2D crystals

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hao Wu ◽  
Wenfeng Zhang ◽  
Li Yang ◽  
Jun Wang ◽  
Jie Li ◽  
...  
Keyword(s):  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Van Der Waals ◽  
Ambient Air ◽  
Critical Importance ◽  
Functional Possibility ◽  
Topological Quantum ◽  
Unit Cells ◽  
Optical And Mechanical Properties ◽  
2D Crystals

AbstractControl of ferromagnetism is of critical importance for a variety of proposed spintronic and topological quantum technologies. Inducing long-range ferromagnetic order in ultrathin 2D crystals will provide more functional possibility to combine their unique electronic, optical and mechanical properties to develop new multifunctional coupled applications. Recently discovered intrinsic 2D ferromagnetic crystals such as Cr2Ge2Te6, CrI3 and Fe3GeTe2 are intrinsically ferromagnetic only below room temperature, mostly far below room temperature (Curie temperature, ~20–207 K). Here we develop a scalable method to prepare freestanding non-van der Waals ultrathin 2D crystals down to mono- and few unit cells (UC) and report unexpected strong, intrinsic, ambient-air-robust, room-temperature ferromagnetism with TC up to ~367 K in freestanding non-van der Waals 2D CrTe crystals. Freestanding 2D CrTe crystals show comparable or better ferromagnetic properties to widely-used Fe, Co, Ni and BaFe12O19, promising as new platforms for room-temperature intrinsically-ferromagnetic 2D crystals and integrated 2D devices.

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