Magnetic Stripe Research Articles

Incommensurate magnetic states induced by ordering competition in

Quantum criticality near a certain magnetic phase transition beneath the superconducting (SC) dome of is attentively studied by virtue of a phenomenological theory in conjunction with the renormalization group approach. We report that ordering competition between magnetic and SC fluctuations is capable of coaxing incommensurate (IC) magnetic states to experience distinct fates depending upon their spin configurations. The C 2-symmetry IC magnetic stripe with a perpendicular magnetic helix dominates over other C 2-symmetry magnetic competitors and hints at a potential candidate for the unknown C 2-symmetry magnetic state. Of the C 4-symmetry IC magnetic phases, the IC charge spin density wave is substantiated to be superior, shedding light on the significant intertwining of charge and spin degrees of freedom. Meanwhile, ferocious fluctuations render a sharp fall in superfluid density alongside a dip in critical temperature as well as intriguing behavior of the London penetration depth.

Modeling Limited-Stop Bus Corridor Services with Fare Payment Mode Choice and Trip Purpose Consideration.

This paper proposes a novel model for optimizing limited-stop bus corridor services with consideration of varied payment modes and different trip purposes. In the proposed model, the bus dwell time at a stop is dependent on the fare payment modes and the number of passengers getting off and waiting at the stop while those with the similar trip purpose are grouped into one user class. Given an origin-destination (OD) passenger trip matrix and a set of candidate bus lines serving a corridor, the proposed model is to minimize the total social cost that consists of the cost to the bus operator and the cost to the passengers. In the formulation of the optimization problem, a weighting parameter is adopted to balance the operator cost and the passenger cost. Numerical examples are presented to illustrate the importance of considering passenger flow impacts on bus (and passenger) travel times in the proposed model. We also investigate effects on the optimal limited-stop services (e.g., short-turn, skip-stop, and express) taking into account the choice of fare payment modes (e.g., on-board fare collection including payment by cash, magnetic strip or smart card, off-board fare collection) and different values of travel time due to passenger trip purposes. It is shown that the off-board payment mode would be more efficient in a high-demand corridor, that more passengers prefer to express and skip-stop services rather than normal regular services in the four collection systems, and that different limited-stop service plans should be used for different periods of the day in response to temporal variation in OD passenger travel patterns. The intellectual merit of this paper is not the seemingly obvious conclusions but that the proposed model can handle the problem of limited-stop bus corridor service design with the consideration of fare payment mode choice and trip purposes.

163 AN AUDIT OF STAFF NAME BADGE VISIBILITY ON A STROKE UNIT IN A LARGE TEACHING HOSPITAL IN IRELAND

Abstract Background The National Patient Experience Survey highlighted the importance of name badge wearing in hospitals, with patients noting that badges made it easier to remember staff and refer to them by name. Based on her experience of identification, the #hellomynameis campaign was initiated in 2013 by Dr. Kate Granger to reinforce the importance of name badge wearing. In an era where mask wearing further inhibits communication and identification, clear identification has never been as important. This audit aims to assess the adherence to name badge wearing on a stroke unit. Methods An observational audit was carried out in March 2022 over one morning. Staff were not notified in advance of the audit. Inclusion criteria: Name badge placed on uniform in a visible place with/without photo. Exclusion criteria: Lanyards with swipe card identification due to small font and difficulty in viewing name and photo. The standard for this audit was for 100% compliance with name badge wearing as name badges are a crucial element of communication in best patient care. Results 24 people across 11 different professions were identified on the ward. Seven staff members (29.16%) were wearing name badges of which 5 included photos therefore the standard set for this audit was not met. Conclusion There was an overall poor compliance with name badge wearing on the stroke ward. Compliance varied amongst the different professions with Speech and Language therapists, Occupational Therapists and nursing staff having a higher compliance with wearing name badges compared to other professions. Most staff members had identification in the form of swipe cards on lanyards, but did not wear clearly legible name badges. Education around the importance of name badges and distribution of name badges to all staff members is planned prior to a re-audit phase.

The Effect of Ne+ Ion Implantation on the Crystal, Magnetic, and Domain Structures of Yttrium Iron Garnet Films

The mechanism of the influence of crystal inhomogeneities on the magnetic and domain microstructures of functional materials based on yttrium iron garnet heterostructures is an important subject of investigation due to the aim to predict parameters for manufacturingpurposes. A study of the structural and magnetic characteristics of a set of yttrium iron garnet films grown on gadolinium–gallium garnet substrate is presented. High-resolution X-ray diffractometry, Mössbauer spectroscopy, MFM, as well as ion implantation simulation and X-ray diffraction simulation were used together to determine the features of the effect of Ne+ ion implantation with different dose rates on the samples. The simulation of ion implantation with E = 82 keV showed energy loss profiles of Ne ions with subsequent defect formation up to amorphization of near-surface layers at high doses. Implantation creates two magnetically non-equivalent types of tetrahedrally located Fe3+ ions, which leads to a rotation of the total magnetic moment relative to the film surface and a change in the width of the magnetic domain stripes.

Scanning magnetometer based on magnetoimpedance sensor for measuring a remnant magnetization of printed toners

In this work, a scanning magnetometer based on a giant magnetoimpedance sensor was used to study the toner material of a black-and-white laser printer that contains iron oxide nanoparticles. We measured the local perpendicular magnetic field component of various sizes black toner strips, magnetized in a perpendicular magnetic field. Our calibration samples were two-wire current lines, which are the current analogue of magnetized toner strips. Magnetic images of the samples were obtained. It was found that investigated toner samples have an average concentration of magnetic nanoparticles per unit area of order of 6 μg/mm2. At this concentration of nanoparticles, the remnant magnetic moment of the sample 1.6 × 5 mm2 in size was about of 0.046 µA⋅m2 and could be reliably registered by the scanning magnetometer. The magnetic image of the toner sample was compared with a hysteresis loop obtained using a vibrating sample magnetometer.

Spontaneous Asymmetry of Chiral Magnetic Domains Within a Magnetic Field

AbstractChiral magnetic domains are topological spin textures in which the Dzyaloshinskii–Moriya interaction assigns a given chirality to the domain walls. Notably, despite rapid progress in chiral magnetic research, one fundamental issue that remains unclear is how the chirality of chiral magnetic domains change as a magnetic field deforms the spin texture. Using spin‐polarized low energy electron microscopy, the evolution of Fe/Ni chiral magnetic stripe domains are investigated in single‐crystalline Fe/Ni/Cu/Co/Cu(001) multilayers in which the interlayer magnetic coupling between the Co and Fe/Ni films serves as an in‐plane magnetic field. Contrary to theoretical works, it is found that the chirality of the Néel walls results in a parallel alignment of the magnetic stripes with the in‐plane magnetic field direction. The transformation of chiral Néel walls into achiral Bloch walls can be precisely controlled by tuning the Cu spacer layer thickness. In addition, the domain wall exhibits a spontaneous asymmetry within the in‐plane magnetic field, leading to an unbalanced chirality between the left‐handed and right‐handed Bloch walls. These new results foster a better understanding of the chiral domain properties within a magnetic field.

Anisotropic magnetoresistance in Mn4−xNixN and the change in the crystalline field

We focus on rare-earth-free anti-perovskite Mn4−xNixN epitaxial films, which can be used for ultrafast current-induced domain wall motion (CIDWM) in magnetic strips. The magneto-transport properties of these materials are very important for a deep understanding of CIDWM. In this study, we investigated the magneto-transport properties of Mn4−xNixN epitaxial films grown on SrTiO3(001) and MgO(001) substrates through anisotropic magnetoresistance (AMR) measurements at temperatures between 2 and 300 K. In samples with a small Ni composition such as x = 0.05−0.1, the AMR ratio of Mn4−xNixN drastically decreased with increasing temperature. We also analyzed the twofold and fourfold symmetries in the AMR curves. Fourfold symmetry is caused by tetragonal crystal fields and is unique to anti-perovskite 3d-metal nitrides such as Mn4N and Fe4N. Only slight fourfold symmetry was observed in Mn4−xNixN. We also performed first-principles calculations with the Vienna ab initio simulation package (VASP) to obtain the projected density of states (PDOS) of d orbitals in Mn4−xNixN, which is responsible for the magnetism of these materials. We conclude that these results are due to the Ni atoms, which function as magnetic impurities and lead to a noticeable change in PDOS, as proved by VASP calculation.

Absence of Walker Breakdown in the Dynamics of Chiral Néel Domain Walls Driven by In-Plane Strain Gradients

The influence of mechanical strain on the static and dynamic properties of chiral domain walls (DWs) in perpendicularly magnetized strips is investigated using micromagnetic simulations and a one-dimensional model. While a uniform strain allows one to reversibly switch the domain-wall configuration at rest between Bloch and N\'eel patterns, strain gradients are suggested as an energy-sustainable means to drive domain-wall motion without the need for magnetic fields or electrical currents. It is shown that an in-plane strain gradient creates a force on a domain wall that drives it towards a region of higher tensile (compressive) strain for materials with positive (negative) magnetostriction. Moreover, due to the dependence of the domain-wall internal energy on the in-plane strain, a damping torque proportional to the local strain arises during motion that opposes the precessional torque due to the driving force, which is proportional to the strain gradient. After a transient period, where both the internal DW angle and the velocity change nonmonotonically, reaching their maximum values asynchronously, the two torques balance each other. This compensation prevents the onset of turbulent domain-wall dynamics, and steady domain-wall motion with a constant velocity is asymptotically reached for an arbitrarily large strain gradient. Despite this complex dynamics, our work shows that average domain-wall velocities in the range of 500 m/s can be obtained using voltage-induced strain in piezoelectric/ferromagnetic devices under realistic conditions.

Random strain induced correlations in materials with intertwined nematic and magnetic orders

Electronic nematicity is rarely observed as an isolated instability of a correlated electron system. Instead, in iron pnictides and in certain cuprates and heavy-fermion materials, nematicity is intertwined with an underlying spin-stripe or charge-stripe state. As a result, random strain, ubiquitous in any real crystal, creates both random-field disorder for the nematic degrees of freedom and random-bond disorder for the spin or charge ones. Here, we put forward an Ashkin-Teller model with random Baxter fields to capture the dual role of random strain in nematic systems for which nematicity is a composite order arising from a stripe state. Using Monte Carlo to simulate this $\textit{random Baxter-field model}$, we find not only the expected break-up of the system into nematic domains, but also the emergence of nontrivial disorder-promoted magnetic correlations. Such correlations enhance and tie up the fluctuations associated with the two degenerate magnetic stripe states from which nematicity arises, leaving characteristic signatures in the spatial profile of the magnetic domains, in the configurational space of the spin variables, and in the magnetic noise spectrum. We discuss possible experimental manifestations of these effects in iron-pnictide superconductors. Our work establishes the random Baxter-field model as a more complete alternative to the random-field Ising model to describe complex electronic nematic phenomena in the presence of disorder.

Microchips in humans: Consumer-friendly app, or new frontier in surveillance?

ABSTRACT There’s a new fad among technology aficionados: voluntarily injecting radio frequency identification chips under their skin. Self-described “bio-hackers” reason that by having such microchips inserted, they can pay for purchases by just hovering their bare hand over a scanner at a checkout counter instead of swiping the magnetic strip of a credit card, inserting a card into a chip reader, or displaying a smartphone app (or doing something as old-fashioned as paying cash). At first glance, such consumer technology looks like a harmless whim, or the next logical step among those who favor piercings, or the supposed ultimate in convenience. But inserting identification microchips in humans would also seem to bear the seeds of a particularly intrusive form of surveillance, at a time when authorities in some parts of the world have been forcibly collecting DNA and other biological data – including blood samples, fingerprints, voice recordings, iris scans, and other unique identifiers – from all their citizens. This article explains some of the nuts and bolts of this hybrid human-machine product.

A More Efficient Approach to Demonstrate Hooke’s Law

Hooke’s law for springs, stating that the force needed to extend or compress a spring by some distance is proportional to that distance, is a topic covered by almost all introductory physics courses at both school and university levels. In this article we present a much more efficient and intuitive approach, compared to the traditional method, for demonstrating Hooke’s law. Figure 1 illustrates the design of our homemade setup. The apparatus consists of a base wooden frame, a hanging bar with a few equally spaced grooves (here we have six) at the top of the wooden frame, a transparent acrylic plate that is embedded into the wooden frame, two magnetic strips, and a thin, straight iron stick.

Magnon Dynamics in Parity-Time-Symmetric Dipolarly Coupled Waveguides and Magnonic Crystals

We consider the magnonic properties of two dipolarly coupled magnetic stripes, both deposited on a normal conductive substrate with strong spin-orbit coupling. A charge current in the substrate acts on the adjacent magnets with spin-orbit torques, which result in magnonic damping or antidamping of the spin waves, and hence a gain-loss coupling of the two magnetic stripes. The whole setup is demonstrated to exhibit features typical for parity-time- ($PT$) symmetric systems. Phenomena are demonstrated that can be functionalized in magnonic devices, including reconfigurable magnonic diodes and logic devices. Alternative stripe designs and $PT$-symmetric, periodic, coupled magnonic textures are studied. Analytical and full numerical analysis identify the conditions for the appearance of exceptional points (EPs), where magnonic gain and loss are balanced and evidence nonreciprocal magnon propagation and enhanced magnon excitation around EPs. Furthermore, the dipolar coupling is shown to bring in a wave-vector-dependent $PT$-symmetric behavior. Proposing and simulating a $PT$-symmetric magnonic crystal, we show how EPs and hence associated phenomena can be steered to a particular wave vector in a gaped spectrum via material design. The phenomena offer additional tools for magnonic based communication and computational devices.

Is Core Angular Momentum Key to the Giant Dynamo?

The pros and cons of core angular momentum dissipation into the convective envelopes of giants as a driver of giant activity is discussed in face of the observational evidence, which points to two ”magnetic strips“, in the HRD, where in the first, at the base of the RGB, activity of moderate mass stars is freshly started and rejuvenated in the second strip, ascending along the mid-AGB. It remains unclear, though, which depths the giant dynamo is operating. Both concentrations of active giants in the HRD are related to stellar evolution phases with core contraction and spin-up, and presumably the dissipation of angular momentum into the convective envelope above. At the same time, the latter has a small Rossby number by virtue of its increasing convective turn-over time—i.e., favourable conditions to run an alpha-omega dynamo. Since coronal X-ray emission appears to give an incomplete picture of stellar activity across the HR diagramme, we here focus on the observed chromospheric emissions across the giant branches and find good agreement with the magnetic field Zeeman-detections there. Stable evolution phases—solar-type main sequence stars with central hydrogen burning and moderate mass, central Helium burning K giants—by contrast demonstrate a decline in activity, apparently imposed by magnetic braking, as such stars are also slower rotators. In that sense, the observed picture of two magnetic activity strips across the HR diagramme could empirically be explained as an interplay of magnetic braking during the stable phase of core helium burning and supply by internal angular momentum during episodes of fast core contraction with core spin-up and angular momentum dredge-up, while meeting dynamo-friendly envelope conditions. At the same time, the sporadic external supply of angular momentum by the engulfment events of a planet, in the course of the evolutionary envelope expansion, may explain some cases of exceptional activity outside the here-described general picture.

Methodology for determining passengers correspondence by public transport from electronic tickets validation operations

Introduction. Current methods for determining passenger ridership, due to their complexity and limited efficiency, do not allow monitoring transport demand at the proper level (in terms of comprehensiveness and continuity). Nowadays, technologies based on the collection, integration and analysis of big data (Urban computing, Big data, Internet of things) are used to create effective solutions in many aspects of our lives (including for urban transit).Materials and methods. Within the framework of this approach, a methodology for determining the correspondence of transit passengers from the operations of validating any kind of electronic travel tickets: smart cards, transport cards, magnetic cards has been developed. Each operations details are recorded in the Automated Fare Collection (AFC) system during the validation.This methodology based on the definition and evaluation the set of acceptable options of passenger trips sequences, which form the passenger correspondence, taking into account many factors that effect on the route choice by a passenger. For example, in contrast to previous studies, the practice of paying for trip at any point on the route, not necessarily immediately after boarding the vehicle, was taken into account.Results. It was proved that passenger correspondence calculated using the developed methodology statistically corresponds to the general set of transit passenger ridership within acceptable errors. The chaacteristics of transit demand is provided in the results.Discussion and conclusion. The application of the developed methodology makes it possible to organize continuous monitoring of passenger flows, technical and operational indicators of the functioning of transit system and thus implement the concept of sustainable development of public transport by designing public transit supply that meets demand.

Air-stable ultrathin Cr3Te4 nanosheets with thickness-dependent magnetic biskyrmions

Two-dimensional (2D) materials with intrinsic magnetism have drawn intense interest for fundamental research and potential application in spintronics and valleytronics. Here we synthesized 2D Cr3Te4 nanosheets with controllable thickness by chemical vapor deposition approach. Reflection magnetic circular dichroism and magneto-transport measurements demonstrated that the Cr3Te4 nanosheets feature excellent environmental stability and have a thickness-dependent ferromagnetic behavior with a high Curie temperature of 165–235 K. Lorentz transmission electron microscopy studies revealed topologically nontrivial magnetic-spin states in the ultrathin Cr3Te4 nanosheets. The magnetic stripe domains in Cr3Te4 can transform into biskyrmion bubbles when an external magnetic field is applied perpendicularly to the nanosheet. The size and density of the biskyrmions can be tuned by the external applied magnetic field and thickness of the nanosheets, respectively. Our findings of topologically nontrivial magnetic-spin states in air-stable 2D magnets could promise new designs of magnetic memory storage, sensors, and spintronics.

Reprogrammable shape transformation of magnetic soft robots enabled by magnetothermal effect

Magnetic soft robots are promising for diverse applications, since they can achieve multimodal locomotion through programming magnetization. However, reprogrammable magnetization of soft robots remains a challenge. Here, we prepare a magnetic elastomer containing both Fe3O4 and CrO2 particles, where Fe3O4 nanoparticles can be heated through the magnetothermal effect. Once the temperature exceeds the Curie point of CrO2 particles, the original magnetization profiles of the elastomer can be erased and re-written. We tune the magnetization profile of a one-dimensional magnetic strip to realize three shape transformation modes, and the reprogrammed magnetization profiles are validated experimentally. The magnetothermal heating process is simulated. We also demonstrate reprogrammable shape transformation of two-dimensional magnetic soft structures. Finally, a reprogrammable hand-shaped soft robot is designed and used as a magnetic switch in a LED circuit.

Subsewershed SARS-CoV-2 Wastewater Surveillance and COVID-19 Epidemiology Using Building-Specific Occupancy and Case Data.

To evaluate the use of wastewater-based surveillance and epidemiology to monitor and predict SARS-CoV-2 virus trends, over the 2020–2021 academic year we collected wastewater samples twice weekly from 17 manholes across Virginia Tech’s main campus. We used data from external door swipe card readers and student isolation/quarantine status to estimate building-specific occupancy and COVID-19 case counts at a daily resolution. After analyzing 673 wastewater samples using reverse transcription quantitative polymerase chain reaction (RT-qPCR), we reanalyzed 329 samples from isolation and nonisolation dormitories and the campus sewage outflow using reverse transcription digital droplet polymerase chain reaction (RT-ddPCR). Population-adjusted viral copy means from isolation dormitory wastewater were 48% and 66% higher than unadjusted viral copy means for N and E genes (1846/100 mL to 2733/100 mL/100 people and 2312/100 mL to 3828/100 mL/100 people, respectively; n = 46). Prespecified analyses with random-effects Poisson regression and dormitory/cluster-robust standard errors showed that the detection of N and E genes were associated with increases of 85% and 99% in the likelihood of COVID-19 cases 8 days later (incident–rate ratio (IRR) = 1.845, p = 0.013 and IRR = 1.994, p = 0.007, respectively; n = 215), and one-log increases in swipe card normalized viral copies (copies/100 mL/100 people) for N and E were associated with increases of 21% and 27% in the likelihood of observing COVID-19 cases 8 days following sample collection (IRR = 1.206, p < 0.001, n = 211 for N; IRR = 1.265, p < 0.001, n = 211 for E). One-log increases in swipe normalized copies were also associated with 40% and 43% increases in the likelihood of observing COVID-19 cases 5 days after sample collection (IRR = 1.403, p = 0.002, n = 212 for N; IRR = 1.426, p < 0.001, n = 212 for E). Our findings highlight the use of building-specific occupancy data and add to the evidence for the potential of wastewater-based epidemiology to predict COVID-19 trends at subsewershed scales.

Application of AI Face Recognition Technology in Swipe Card Attendance Systems for Hospitals

Traditional swipe card attendance systems for hospitals cannot effectively protect employees’ personal information and ensure that the employees are swiping their own cards. To solve the problem, the present study proposes a novel hospital swipe card attendance system using an artificial intelligence (AI) face modeling system with an open-source face database. The proposed system employs a multi-task cascaded convolutional network (MTCNN) algorithm and FaceNet to improve the performance of face recognition. The system can compare the face of the one who swipes a card with the faces of cardholders in the database, thereby preventing the one from clocking in on behalf of others. The results show that the application of AI technology in the hospital swipe card attendance system can realize the promise of protecting employees’ personal information and verifying employees’ identities.

Sign Language Based ATM Accessing System for the Visually Impaired

Around 285 million individuals all throughout the planet are outwardly hindered and around 35 million are visually impaired. There are 3 sorts of visual impairment night visual impairment, complete visual impairment, and Color visual impairment. One of the issues they face in their routine is during ATM exchanges. Despite the fact that ATMs are recorded with Braille it doesn't totally wipe out the issues looked by dazzle individuals. But the main problem faced by them is performing monitory transaction how difficult for a blind to withdraw money form ATM and the risk in the world .Thus in order to enhance his security while withdrawing money from the ATM we plan to develop a secure environment for them , by designing sign language based ATM accessing system. Concept of real time video processing will be incorporated for the realization of the same. Further it has been noticed that they face difficulty in inserting their ATM card in the designated slot. Thus instead of using magnetic strip based card, we proposed colour coded ATM card, which allows them to access the account upon placing the card in front the camera, the same camera will be utilized to identify the gesture as their pin.

Early post-breakup kinematic adjustments of continental–oceanic transform fault zones: Cape Range, Coromandal and Romanche transform margin case study

Abstract A comparison of transform margins that started their evolution as continental transforms shows differences in their tectonic style, which can be attributed to the variable kinematic adjustments they underwent during the post-breakup continental-oceanic stage of their development. Three end-member examples are presented in detail. The Cape Range transform fault zone (Western Australia) retained its strike-slip character during its entire continental-oceanic stage, as documented by the transform-perpendicular system of spreading-related magnetic stripe anomalies. The Coromandal transform fault zone (Eastern India) adjusted its kinematics to a transtensional one during its continental-oceanic stage, as indicated by the transform-oblique system of magnetic stripe anomalies and extensional component of movement indicated by a narrow zone of crustal thinning. The Romanche transform fault zone (Equatorial Africa) adjusted its kinematics to transpressional, as documented by the changing geometries of magnetic stripe anomalies and transpressional folding during its continental-oceanic development stage. Based on the recognition of the aforementioned adjustments, we suggest a new categorization of transforms into (1) those that experience transpressional adjustment, (2) those that experience transtensional adjustment and (3) those that do not experience any adjustment during their continental-oceanic development stage.