Edge Of Wire Research Articles

Drastic enhancement of stable and fast domain wall motion in GdFe nanowires through laser-annealing treatment at wire edges

One of the key challenges in racetrack memory (RM) technology is achieving stable and high velocities for domain walls (DWs) while maintaining low power consumption. In our study, we propose a novel laser-annealing (LA) process to modify wire edges for a smoother DW movement along the nanowire. In this regard, a film stack of Pt (5 nm)/Gd26Fe74(20 nm)/SiN(10 nm) was deposited by magnetron sputtering. The DW velocity in the wire was measured by applying single voltage pulses and then observing the DW motion using a Kerr microscope. The current-induced domain walls motion measurements have shown that the LA process significantly enhances the velocity of DW motion. The LA of both edges of the nanowire results in a threefold increase in DW velocity compared to non-LA conditions. Further experiments illustrated that the DW velocity remains stable for the laser-annealed condition across a wide range of applied currents, spanning from 3 × 1011 to 7 × 1011 A/m2. Additionally, our investigation into the magnetic characteristics of laser-annealed nanowire regions exhibited a notable reduction of Hc at the laser-annealed edges. This decrease in Hc indicates greater ease in manipulating the material’s magnetization, which is essential for efficient DW motion. Furthermore, we explored the influence of LA on the Dzyaloshinskii–Moriya Interaction (DMI) field. The DMI finding underscores the strong correlation between DMI fields and DW speed. This achievement, i.e. the stability and consistency of the domain’s velocity (as the components of an RM) in a wide range of applied current, is significant progress in the field of operation and industrialization of RM.

Boosting domain wall velocity and stability in ferrimagnetic GdFe nanowires by applying laser-annealing process

This study highlights the significant achievement of enhancing domain wall (DW) velocity through the laser-annealing (LA) process in GdxFe100−x films, with a specific focus on the Gd26Fe74 composition. By investigating the current-induced DW motion, it was observed that the LA process on the edges and middle of the nanowires resulted in a remarkable improvement in DW velocity from around 600 m/s for non-laser-annealed to 1800 m/s for laser-annealed conditions. Furthermore, we conducted additional experiments to explore the stability and dynamics of a system involving DWs in a single wire. The experimental results revealed a stable and uniform movement of the DWs, as evidenced by a velocity of approximately 1800 m/s, even after the application of 20 pulses with a short pulse width of 1 ns. The resulting stability of the DW motion across a wide range of applied currents demonstrates the practical significance of the LA in achieving high-performance racetrack memories. Our findings suggest that the LA process has a similar effect on both the middle and edge treatments of the wire. This indicates that structural defects on the wire's edges are not the main cause of the observed low velocity or curvy shape of DWs. One possible mechanism for this effect is the reduction of the Ku value through the LA process. This study establishes a ground-breaking advancement by showcasing the effectiveness of the LA in enhancing DW motion velocity in GdFe ferrimagnetic thin films, thereby opening avenues for future research and industrial applications in this field.

Dissimilar Welding of AISI 304 and AISI 310 Steels Using Metal Inert Gas Welding

Thermal, mechanical and chemical properties decides the quality of welding dissimilar metals, as controlling of welding variables is difficult to achieve the desired output of weld joint. Welding of dissimilar metals is a difficult task, as one has to take care of the metallurgical changes taking place in both the metals due to heat produced during welding. Proper selection of welding variables plays an important role in obtaining sound weld joint. Austenitic stainless steel plates of AISI 304 and AISI 310 are welded by MIG welding. Three factors namely filler wire feed rate, welding current and edge included angle are taken as input variables of welding. Grain size and hardness are the output variables. Fifteen combinations of experiments are conducted by considering Box Benhken Design for three factors and three levels. The effect of welding variables on grain size and hardness of the welded joint was studied. The welding variables were optimised using Response optimizer for minimum grain size and maximum hardness of weld joint.

Machine vision-based transverse vibration measurement of diamond wire

Diamond wire sawing is one of the key technologies for wafering in the semiconductor industry. The transverse vibration of the wire during sawing will generate additional displacement that not only reduces the as-cut wafer quality but increases the critical adhesion gap between the wires, which is an important factor limiting the development of diamond wire slicing technology toward narrower kerf loss and thinner as-cut wafer. The vibration measurement of the diamond wire provides an indispensable test basis for its vibration control. Therefore, a machine vision-based transverse vibration measurement method of diamond wire is developed in this paper. The approximate edge position of the wire in the image midline is obtained to crop the region of interest in the image by using the maximum continuous same-directional pixel gradient algorithm and thus reduce the computing time. The wire edges in the image are accurately extracted by an adaptive image segmentation method proposed based on the image histogram. According to the surface topography characteristics of diamond wire, a feature extraction algorithm based on the multiple inward line fitting using the least square method is proposed, which can effectively detect the position of the inner diameter boundary of the diamond wire. Accordingly, the equation of the central axis of the wire in the image is obtained to realize the transverse vibration detection of the diamond wire. To conclude, a diamond wire vibration measurement experiment is conducted and the machine vision detection results are compared with the vibration displacement measured by the accelerometer at the same position of the wire end. The results show that the measurement error of the machine vision vibration inspection is generally small for the different types of diamond wires and the different frequencies of the wire transverse vibration, which means that the measurement method proposed in this paper has good accuracy, and applicability, and robustness.

Infrared Visual Sensing Detection Approach of Swing Arc Narrow Gap Weld Deviation Based on Outlier Data Filtering

Narrow gap arc welding interferences pose notable challenges to accurate weld deviation detection in infrared visual sensing. An outlier data filtering (ODF) approach is proposed to precisely detect weld deviation between the groove and the torch centers after eliminating the welding-induced intense disturbances in images. The ODF approach develops a global pattern recognition (GPR) based algorithm to detect the groove center, and an optimal-estimation based position consistency filtering (PCF) algorithm to locate the torch center. In addition, ODF also modifies a welding image processing procedure to prepare the groove and the wire edges for the center detections. Experimental results show that the GPR algorithm removes the simulated welding spatters of ≤ 2.48 mm diameters on the groove edge, and the PCF algorithm accurately gains the torch center with the detection error of−0.022 ~ +0.035 mm. Finally, the ODF approach realizes a precise detection of the weld deviation with the detection error of−0.107 ~ +0.079 mm, demonstrating the effectiveness of the proposed approach regardless of welding interferences.

Fabrication of superconducting coils and (Ba,A)Fe2As2 (A:Na, K) long round wires with large superconducting cores

We fabricated superconducting coils using 10-20 m-class round wires of 122-type iron-based superconductors (IBSs). Round wires and coils are fabricated by powder-in-tube method and hot-isostatic-press technique. Transport critical current (I c) of the whole (Ba,K)Fe2As2 coil is 46 A under the self-field at 4.2 K, and magnetic field at the center of the coil reaches 0.3 T. Although the edge of the long wire in the coil is damaged, the rest of the part is relatively homogeneous. Furthermore, the largest transport critical current density (J c) and I c in (Ba,K)Fe2As2 wires picked up from the coil reach 49 kAcm−2 and 44 A at 4.2 K under a magnetic field of 10 T, respectively. This value exceeds the previous highest transport J c of (Ba,K)Fe2As2 round wires. We also fabricated a (Ba,Na)Fe2As2 coil using long round wire with large superconducting core by react and wind method. Transport I c of the coil is significantly low due to cracks perpendicular to electric current flow direction, although magnetic J c in the round wire picked up from the coil reaches 40 kAcm−2 at 4.2 K under 4 T.

Highly Transparent and Polarization-Maintained Terahertz Plasmonic Metamaterials Based on Metal-Wire-Woven Hole Arrays: Fundamentals and Characterization of Transmission Spectral Peaks.

Metal-hole-supported terahertz (THz) waves through the structure of a metal-wire-woven hole array (MWW-HA) present high-frequency-passed transmittance spectra of one plasmonic metamaterial with artificial plasmonic frequencies, which are inversely proportional to metal-hole widths. For the transmitted THz waves of MWW-HA, transverse-electric (TE) and transverse-magnetic (TM) waveguide modes mix within a symmetric metal-hole boundary. THz resonance waves transversely crossing the holes of MWW-HA are experimentally characterized with spectral peaks in the frequency range of 0.1–2 THz that are correlated with aperture sizes, unit-cell-hole widths, metal-wire thicknesses, and wire-bending angles. The metal-hole-transported resonance waves of MWW-HA are dominated by TE waveguide modes instead of TM ones because a hole width of MWW-HA is approximate to the half wavelength of a resonance wave. The round metal edges of the woven metal wires can minimize the effective optical length of a thick metal hole to transmit THz resonance waves, thereby resulting the smallest rotation angle of linear polarization and high transmittance up to 0.94. An MWW-HA structure is therefore reliable for supporting metal-hole resonance waves with low resistance, whereas a metal-slab-perforated hole array cannot achieve the same result.

Cuffed endotracheal tube as a cardiopulmonary bypass venous return cannula.

Cuffed endotracheal tube as a cardiopulmonary bypass venous return cannula.

Majorana Zero Modes in Ferromagnetic Wires without Spin-Orbit Coupling

We present a novel controllable platform for engineering Majorana zero modes. The platform consists of a ferromagnetic metallic wire placed among conventional superconductors, which are in proximity to ferromagnetic insulators. We demonstrate that Majorana zero modes emerge localised at the edges of the ferromagnetic wire, due to the interplay of the applied supercurrents and the induced by proximity exchange fields with conventional superconductivity. Our mechanism does not rely on the pairing of helical fermions by combining conventional superconductivity with spin-orbit coupling, but rather exploits the misalignment between the magnetization of the ferromagnetic insulators and that of the ferromagnetic wire.

Current-induced perpendicular magnetization switching without external magnetic field in gate-induced asymmetric structure

We demonstrate current-induced switching of perpendicular magnetization without any external magnetic field by introducing lateral structural asymmetry through gate-induced redox reactions. A gate electrode was fabricated to cover only half of a heavy metal/ferromagnet/oxide wire, allowing a gate voltage to form an in-plane oxidation gradient. The essential role of structural asymmetry is evidenced by the fact that external-field-free deterministic switching is absent when the gate electrode covers an entire wire. We confirm that the current-induced perpendicular effective field deterministically drives the magnetization direction at zero field. Magnetic domain imaging and transport measurements clarify that the origin of the perpendicular effective field is not the Rashba effect, but the Oersted field at the wire edges.

Oblique drive tolerance of elliptical skyrmions moving in perpendicularly magnetized nanowire

A magnetic skyrmion is stabilized via the Dzyaloshinskii–Moriya interaction in a perpendicularly magnetized thin nanowire. When the skyrmion is driven by a spin-transfer torque due to spin currents flowing through the wire, the skyrmion approaches the wire edge owing to the skyrmion Hall effect. In other words, the skyrmion moves obliquely along the longitudinal direction of the wire. The skyrmion often breaks or disappears because of this oblique motion. In this study, we propose an elliptical skyrmion to prevent this disappearance. We simulated the current-induced motion of an elliptical skyrmion produced in a wire through a micromagnetic approach. The elliptical skyrmion was also moved obliquely to the longitudinal direction of the wire. When a small current flowed through the wire, the skyrmion moved in the longitudinal direction of the wire after it approached the wire edge. When a larger current flowed through the wire, the skyrmion disappeared after it approached the wire edge. The elliptical skyrmion can be driven over a long distance with a larger current compared to a circular skyrmion. The motion of the skyrmion approaching the wire edge was analyzed using Thiele’s equation, with an external force. We estimated the external force from the simulation results of the skyrmion motion. The external force was proportional to the distance between the skyrmion edge and the wire edge. The results of this study indicate that using the elliptical skyrmion as a binary digit in a magnetic memory, such as a skyrmion-based racetrack memory, can be advantageous in term of the stability of the binary digit.

Scanning electron microscope analysis of working ends of standard and modified Gracey curettes.

Context:Gracey curettes are the most frequently used manual instruments in periodontal treatments.Aim:This study aimed to evaluate morphology of working ends of standard and modified Gracey curettes no. 1–2.Materials and Methods:Using scanning electron microscopy, four batches of unused standard curettes from seven manufacturers and modified curettes from 6 manufacturers were investigated for blade length, blade width, blade thickness, toe morphology, surface roughness, and cutting-edge morphology.Results:Working ends of the standard Gracey curettes were longer than the modified ones, with mean lengths of 5.65 ± 0.68 and 4.42 ± 0.82 mm, respectively. However, both standard and modified Gracey curettes had comparable widths and thicknesses, with the mean width of 0.86 mm and the mean thickness of 0.71 mm. Most samples had acceptably symmetrical toes, except those from three manufacturers which had unacceptable toes with angulations. Moreover, only two manufacturers produced curettes with smooth blades on all their surfaces. In addition, sharp or functional wire edges were seen in cutting edges of curettes from three manufacturers.Conclusions:Working ends of standard and modified Gracey curettes could have different morphological features if they were from different manufacturers or different batches. It is suggested that dentists or dental hygienists make a purchase decision based on their knowledge on morphology of a good curette in relation to its intended use in dental practice, rather than their familiarity or the curette's price. Furthermore, the curette needs to be examined using a widely available magnifying device when possible.

Visualizing the strongly reshaped skyrmion Hall effect in multilayer wire devices

Magnetic skyrmions are nanoscale spin textures touted as next-generation computing elements. When subjected to lateral currents, skyrmions move at considerable speeds. Their topological charge results in an additional transverse deflection known as the skyrmion Hall effect (SkHE). While promising, their dynamic phenomenology with current, skyrmion size, geometric effects and disorder remain to be established. Here we report on the ensemble dynamics of individual skyrmions forming dense arrays in Pt/Co/MgO wires by examining over 20,000 instances of motion across currents and fields. The skyrmion speed reaches 24 m/s in the plastic flow regime and is surprisingly robust to positional and size variations. Meanwhile, the SkHE saturates at ∼22∘, is substantially reshaped by the wire edge, and crucially increases weakly with skyrmion size. Particle model simulations suggest that the SkHE size dependence — contrary to analytical predictions — arises from the interplay of intrinsic and pinning-driven effects. These results establish a robust framework to harness SkHE and achieve high-throughput skyrmion motion in wire devices.

Prosthetic Arch Branch Graft Injury by a Fractured Sternal Wire: A Word of Caution

A 74-year-old man with a history of bronchial asthma underwent total arch replacement and coronary artery bypass grafting. He was discharged without any major complications except for postoperative coughing attacks, which caused a third sternal wire fracture and partial sternal dehiscence (Figure 1A, Figures 2A and D). He was asymptomatic and without sternal instability at 3 months after surgery. However, chest radiography (CXR) revealed migration of the fractured sternal wire (Figure 1B), and computed tomography (CT) showed close contact between the edge of the fractured sternal wire and the arch branch graft to the left subclavian artery (LSCA) (Figures 2B and E).

Oxidative vaporization etching for molybdenum tip formation in air

Oxidative vaporization in air using a flame with a temperature range of 1950–2300 K was employed for controlling the tip shape made from a nipper-cut metal molybdenum (Mo) wire edge. An extremely high vapor pressure of MoO3 generated on the Mo surface in flame is a driving force behind the tip shape formation. Since the MoO3 vaporization rate follows the flame temperature gradient, we could control the tip apex shape by selecting the proper flame etching condition. The best condition to obtain a sharp tip apex based on statistical tests of dozens of Mo tips was obtained by Mo wire edge insertion into the 2100 K flame from the side for one second. This was repeated twice, which reproducibly provided a tip apex with a radius of 50–100 nm and a cone angle of 20–30 degrees. The present Mo tips, fabricated without aqueous solutions, were examined for their suitability as probe tips through air-scanning tunneling microscopy (STM), ultrahigh vacuum STM, field emission spectroscopy, and conductance measurements.

The Effects of Load Location on Dropper Stress in a Catenary System for a High-Speed Railway

In this paper, the effects of load location on dropper stress are studied. We treat contact wire as a beam element and derive its response equation and then deduce the stress equation of dropper. A computer code based on MATLAB is written to calculate dropper stress using the finite difference method. The results show that there are three stages during the period of the stress changes of dropper, including instant rebound, damped sinusoidal vibration, and bending compression. The shorter the distance away from a load is, the larger the vertical displacement of the dropper is, which results in the corresponding increases of its stress amplitude and the maximum tensile stress. The load location has a significant impact on the stress changes of dropper. Compared to the condition of the load in the middle, the load acting on the edge of contact wire could induce the larger tensile stress when both ends of contact wire are considered as free boundaries. Therefore, it is necessary to add supports at both ends.

Shearing and Shaving Process of Stainless Steel Wire at Micro Scale

This study investigated the effects of the die clearance on the shearing and shaving processes of the stainless steel (SUS316LVM) wire at micro scale. A die set was developed and installed on a precession press equipped with a load cell and a displacement sensor to conduct experiments. By using different punches in the same die set, the specimens prepared from 316LVM stainless steel wires with 0.5 mm diameter were first sheared and then shaved. Experimental results show that the burnished area of the sheared edge increases with the reduction of the clearance between the punch and die in the shearing process. The clearance also significantly affects the load curves. Moreover, the shaving process does increase the burnished area on the shaved edge of the specimen. By an appropriate feed in the shaving process, it is possible to trim the extra material from the sheared edge that results in a nearly complete burnished surface on the shaved edge of the stainless steel wire. This research provides a basis for understanding of the die clearance effect on the shearing and shaving processes at micro scale.

Magnetic domain wall curvature induced by wire edge pinning

In this study, we report on the analysis of the magnetic domain wall (DW) curvature due to magnetic field induced motion in Ta/CoFeB/MgO and Pt/Co/Pt wires with perpendicular magnetic anisotropy. In wires of 20 μm and 25 μm, a large edge pinning potential produces the anchoring of the DW ends to the wire edges, which is evidenced as a significant curvature of the DW front as it propagates. As the driving magnetic field is increased, the curvature reduces as a result of the system moving away from the creep regime of DW motion, which implies a weaker dependence of the DW dynamics on the interaction between the DW and the wire edge defects. A simple model is derived to describe the dependence of the DW curvature on the driving magnetic field and allows us to extract the parameter σE, which accounts for the strength of the edge pinning potential. The model describes well the systems with both weak and strong bulk pinning potentials like Ta/CoFeB/MgO and Pt/Co/Pt, respectively. This provides a means to quantify the effect of edge pinning induced DW curvature on magnetic DW dynamics.

Valley polarized current and resonant electronic transport in a nonuniform MoS2 zigzag nanoribbon

Using the tight-binding approach we study the electronic transport in a $\mathrm{MoS}_2$ zigzag ribbon with a spatially varying potential profile. Considering a ribbon with a smooth potential step in the Fermi energy regime where the transport is dominated by the edge modes, we find that the conductance exhibits sharp resonances due to the resonant transport through a n-p-n junction effectively created in the structure. We show that in a gated wire the current carried on the wire edges can be blocked despite the metallic band structure of the ribbon. For the Fermi energies corresponding to $\mathrm{MoS}_2$ bulk conduction band, we identify states of the semi-infinite wire that are polarized in the $K$, $K'$, $Q$ valleys and exhibit the valley Hall effect distinctly visible in a nonuniform ribbon. Finally, we show that well-defined momenta of the valley polarized modes allow nearly complete valley polarization of the current in a locally gated ribbon.

Multipartite entanglement transfer in spin chains

We investigate the transfer of genuine multipartite entanglement across a spin-12 chain with nearest-neighbour XX-type interaction. We focus on the perturbative regime, where a block of spins is weakly coupled at each edge of a quantum wire, embodying the role of a multiqubit sender and receiver, respectively. We find that high-quality multipartite entanglement transfer is achieved at the same time that three excitations are transferred to the opposite edge of the chain. Moreover, we find that both a finite concurrence and tripartite negativity is attained at much shorter time, making GHZ-distillation protocols feasible. Finally, we investigate the robustness of our protocol with respect to non-perturbative couplings and increasing lengths of the quantum wire.