scholarly journals Configuration-sensitive transport at the domain walls of a magnetic topological insulator

2018 ◽  
Vol 98 (16) ◽  
Author(s):  
Yan-Feng Zhou ◽  
Zhe Hou ◽  
Qing-Feng Sun
Keyword(s):  
Topological Insulator ◽  
Domain Walls

scholarly journals Controllable quantum point junction on the surface of an antiferromagnetic topological insulator

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Nicodemos Varnava ◽  
Justin H. Wilson ◽  
J. H. Pixley ◽  
David Vanderbilt
Keyword(s):  
Topological Insulator ◽  
Information Science ◽  
Domain Walls ◽  
Quantum Hall ◽  
Edge State ◽  
Wave Functions ◽  
Quantum Hall Systems ◽  
Electron Quantum ◽  
Quantum Point ◽  
Higher Temperature

AbstractEngineering and manipulation of unidirectional channels has been achieved in quantum Hall systems, leading to the construction of electron interferometers and proposals for low-power electronics and quantum information science applications. However, to fully control the mixing and interference of edge-state wave functions, one needs stable and tunable junctions. Encouraged by recent material candidates, here we propose to achieve this using an antiferromagnetic topological insulator that supports two distinct types of gapless unidirectional channels, one from antiferromagnetic domain walls and the other from single-height steps. Their distinct geometric nature allows them to intersect robustly to form quantum point junctions, which then enables their control by magnetic and electrostatic local probes. We show how the existence of stable and tunable junctions, the intrinsic magnetism and the potential for higher-temperature performance make antiferromagnetic topological insulators a promising platform for electron quantum optics and microelectronic applications.

scholarly journals Quantized chiral edge conduction on domain walls of a magnetic topological insulator

Science ◽  
2017 ◽  
Vol 358 (6368) ◽  
pp. 1311-1314 ◽  
Author(s):  
K. Yasuda ◽  
M. Mogi ◽  
R. Yoshimi ◽  
A. Tsukazaki ◽  
K. S. Takahashi ◽  
...  
Keyword(s):  
Topological Insulator ◽  
Domain Walls

scholarly journals Magnetic Imaging of Domain Walls in the Antiferromagnetic Topological Insulator MnBi2Te4

Nano Letters ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 2609-2614 ◽  
Author(s):  
Paul M. Sass ◽  
Wenbo Ge ◽  
Jiaqiang Yan ◽  
D. Obeysekera ◽  
J. J. Yang ◽  
...  
Keyword(s):  
Topological Insulator ◽  
Domain Walls ◽  
Magnetic Imaging

scholarly journals Experimental realization of a reconfigurable electroacoustic topological insulator

2020 ◽  
Vol 117 (28) ◽  
pp. 16138-16142 ◽  
Author(s):  
Amir Darabi ◽  
Manuel Collet ◽  
Michael J. Leamy
Keyword(s):  
Topological Insulator ◽  
Elastic Waves ◽  
Domain Walls ◽  
Frequency Range ◽  
Finite Frequency ◽  
Experimental Realization ◽  
Interface Waves ◽  
Back Scattering ◽  
Sharp Edges ◽  
Valley Hall Effect

A substantial challenge in guiding elastic waves is the presence of reflection and scattering at sharp edges, defects, and disorder. Recently, mechanical topological insulators have sought to overcome this challenge by supporting back-scattering resistant wave transmission. In this paper, we propose and experimentally demonstrate a reconfigurable electroacoustic topological insulator exhibiting an analog to the quantum valley Hall effect (QVHE). Using programmable switches, this phononic structure allows for rapid reconfiguration of domain walls and thus the ability to control back-scattering resistant wave propagation along dynamic interfaces for phonons lying in static and finite-frequency regimes. Accordingly, a graphene-like polyactic acid (PLA) layer serves as the host medium, equipped with periodically arranged and bonded piezoelectric (PZT) patches, resulting in two Dirac cones at theKpoints. The PZT patches are then connected to negative capacitance external circuits to break inversion symmetry and create nontrivial topologically protected bandgaps. As such, topologically protected interface waves are demonstrated numerically and validated experimentally for different predefined trajectories over a broad frequency range.

The direct determination of magnetic domain wall profiles using a split detector STEM

1978 ◽  
Vol 36 (1) ◽  
pp. 466-467
Author(s):  
J.N. Chapman ◽  
P.E. Batson ◽  
E.M. Waddell ◽  
R.P. Ferrier
Keyword(s):  
Electron Microscope ◽  
Domain Wall ◽  
Transmission Electron Microscope ◽  
Domain Walls ◽  
Photographic Plate ◽  
Magnetic Domain ◽  
Direct Determination ◽  
Quantitative Information ◽  
Scanning Transmission Electron Microscope ◽  
Transmission Electron

By far the most commonly used mode of Lorentz microscopy in the examination of ferromagnetic thin films is the Fresnel or defocus mode. Use of this mode in the conventional transmission electron microscope (CTEM) is straightforward and immediately reveals the existence of all domain walls present. However, if such quantitative information as the domain wall profile is required, the technique suffers from several disadvantages. These include the inability to directly observe fine image detail on the viewing screen because of the stringent illumination coherence requirements, the difficulty of accurately translating part of a photographic plate into quantitative electron intensity data, and, perhaps most severe, the difficulty of interpreting this data. One solution to the first-named problem is to use a CTEM equipped with a field emission gun (FEG) (Inoue, Harada and Yamamoto 1977) whilst a second is to use the equivalent mode of image formation in a scanning transmission electron microscope (STEM) (Chapman, Batson, Waddell, Ferrier and Craven 1977), a technique which largely overcomes the second-named problem as well.

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.

Temperature Dependence of Magnetic Domains and Wall Structures

1972 ◽  
Vol 30 ◽  
pp. 496-497
Author(s):  
Sonoko Tsukahara ◽  
Tadami Taoka ◽  
Hisao Nishizawa
Keyword(s):  
Temperature Dependence ◽  
Domain Walls ◽  
Magnetic Domain ◽  
Iron Film ◽  
Objective Lens ◽  
Lorentz Microscopy ◽  
Domain Structures ◽  
Wall Structures ◽  
Crystal Films ◽  
Metallurgical Structure

The high voltage Lorentz microscopy was successfully used to observe changes with temperature; of domain structures and metallurgical structures in an iron film set on the hot stage combined with a goniometer. The microscope used was the JEM-1000 EM which was operated with the objective lens current cut off to eliminate the magnetic field in the specimen position. Single crystal films with an (001) plane were prepared by the epitaxial growth of evaporated iron on a cleaved (001) plane of a rocksalt substrate. They had a uniform thickness from 1000 to 7000 Å.The figure shows the temperature dependence of magnetic domain structure with its corresponding deflection pattern and metallurgical structure observed in a 4500 Å iron film. In general, with increase of temperature, the straight domain walls decrease in their width (at 400°C), curve in an iregular shape (600°C) and then vanish (790°C). The ripple structures with cross-tie walls are observed below the Curie temperature.

Sign in / Sign up

Export Citation Format

Share Document