Magnetic Field In Different Directions Research Articles

Direct and inverse magnetocaloric effects in magnetostrictive GdMn2Ge2 with field-induced metamagnetic transition

Heavy rare-earth-based ternary intermetallic compounds with the formula RT2X2 have drawn great interest because of their multiple magnetic transitions and various magnetic structures. Here, anisotropic magnetic behaviors, magnetocaloric effects (MCEs), and magnetostriction effects in single-crystalline GdMn2Ge2 are studied in two different directions. Experiments show a magnetic transition characterized by a sudden decrease in magnetization for μ0H//a and a sharp increase for μ0H//c at Tt. The transition is driven by lower temperatures for μ0H//a, contrasting that for μ0H//c with an increase in the magnetic field. An inverse MCE is observed for μ0H//a with a maximum magnetic entropy change (−ΔSMmax) of −7.4 J kg−1 K−1 (μ0ΔH = 6 T), while a direct MCE is obtained for μ0H//c with an −ΔSMmax of 8.0 J kg−1 K−1 under the same magnetic field change. Moreover, a remarkable field-induced metamagnetic transition and a magnetostriction effect are observed simultaneously at Tt, indicating strong magneto-lattice coupling. The T-μ0H phase diagrams are constructed based on the magnetic properties. The coexistence of direct and inverse MCEs is discussed and is due to the spin-flop of Mn and anisotropic magnetic properties under magnetic fields in different directions.

Optimal weak measurement scheme for chiral molecular detection based on photonic spin Hall effect.

In this paper, we propose a precision method to measure the chiroptical signal of Artemisinin solutions using the photonic spin Hall effect (PSHE) on the Ce:YIG-YIG-SiO2 structure as a probe. The effects of transmission distance, incident angles, applied magnetic fields of different directions, and beam waist of light on the weak measurement system are analytically investigated through simulations. It is found that decreasing the beam waist of the incident spot, increasing the incident angle, increasing the transmission distance, and adding a longitudinal magnetic field is conducive to enhancing the amplification transverse shift of PSHE, thus the measurement sensitivity is greatly improved. Based on the optimal weak measurement scheme, the detection limit for concentration measurement of artemisinin based on optical rotatory (OR) was reduced to 0.05 mg/ml. The measurement precision of the OR angle has been improved to 10-7rad.

Large anomalous Hall effect and unusual domain switching in an orthorhombic antiferromagnetic material NbMnP

Specific antiferromagnetic (AF) spin configurations generate large anomalous Hall effects (AHEs) even at zero magnetic field through nonvanishing Berry curvature in momentum space. In addition to restrictions on AF structures, suitable control of AF domains is essential to observe this effect without cancellations among its domains; therefore, compatible materials remain limited. Here we show that an orthorhombic noncollinear AF material, NbMnP, acquired AF structure-based AHE and controllability of the AF domains. Theoretical calculations indicated that a large Hall conductivity of ~230 Ω−1cm−1 originated from the AF structure of NbMnP. Symmetry considerations explained the production of a small net magnetization, whose anisotropy enabled the generation and cancellation of the Hall responses using magnetic fields in different directions. Finally, asymmetric hysteresis in NbMnP shows potential for the development of controllability of responses in AF materials.

Production of magnetic field due to heavy ion collisions around transition energy

Isospin quantum molecular dynamics (IQMD) model is a reliable computational tool for the study of various phenomena (multi fragmentation, anisotropic flow, nuclear stopping) from low to intermediate heavy ion collisions (HICs). Here, simulation has been carried out for the magnetic field generated during non-central HICs using the IQMD model. The effect of various parameters, such as centrality, angular momentum, rapidity and incident energy has been thoroughly investigated on the magnetic field with the evolution of time and space. It has been observed that the rapidity bin significantly impacts the magnitude of the magnetic field in different directions. Furthermore, the magnetic field produced during HIC leads to a notable impact on the in-plane momentum of the proton and neutron.

Effects of Magnetic Fields in Arc Welding, Laser Welding, and Resistance Spot Welding: A Review

The pictures show the effect of magnetic fields in different directions, including welding direction, transverse, longitudinal and cusp magnetic fields, on the shape of welding arc and molten pool. The magnetic field can significantly affect the arc morphology and droplet transfer, as well as the macro morphology and microstructure of the weld bead. Further information can be found in the article, number 2200682 by Yonghua Shi, and co-workers.

The influence of magnetic field on the beam quality of relativistic electron beam long-range propagation in near-Earth environment

In recent years, it has been proposed to use satellite-mounted radio-frequency (RF) accelerators to produce high-current relativistic electron beams to complete debris removal tasks. However, when simulating the long-range propagation (km-range) process of the electron beam, it is difficult to directly use the particle-in-cell method to simultaneously consider the space charge effect of beam and the influence of the geomagnetic field. Owing to these limitations, in this paper, we proposed a simplified method. The ps-range electronic micropulses emitted by the RF accelerator were transmitted and fused to form a ns-range electron beam; then, combined with the improved moving window technology, the model was constructed to simulate the long-range propagation process of the relativistic electron beam in near-Earth environment. Finally, by setting the direction of movement of the beam to be parallel, perpendicular and at an inclination of 3° to the magnetic field, we analyzed and compared the effects of the applied magnetic fields in different directions on the quality of the beam during long-range propagation. The simulation results showed that the parallel state of the beam motion and magnetic fields should be achieved as much as possible to ensure the feasibility of the space debris removal.

Dynamic analysis and active control of hard-magnetic soft materials

ABSTRACT The hard-magnetic soft materials which can sustain high residual magnetic flux density gradually attract the attention of researchers because of potential applications in soft robotics and biomedical fields. In this work, we focus on the dynamic response of hard-magnetic soft materials. The dynamic motion equations are derived by the Euler-Lagrange equation. The effects of the aspect radio on the nonlinear vibration of the hard-magnetic soft cuboid under the force and applied magnetic fields in different directions are investigated. The amplitude-frequency curves demonstrate that the aspect ratio also has an influence on the frequency and amplitude of the primary resonance. Moreover, to eliminate undesired vibration responses, the PID controller is applied to the vibration of the hard-magnetic soft materials, and the desired results can be obtained.

Terahertz Characteristics of Magnetic Fluid Based on Microfluidic Technology

Magnetic fluid is a new functional material with both liquid fluidity and solid magnetism, which has important application value in medicine, biology, and so on. In this study, terahertz technology and microfluidic technology were combined to investigate the terahertz transmission characteristics of a magnetic fluid in different magnetic fields and different electric fields. In the external magnetic field, the intensity of the terahertz spectrum increased with an increase in the magnetic field intensity, and the response to the magnetic field in different directions was different. Under the applied electric field, the intensity of the terahertz spectrum decreased with an increase in the electric field intensity. This method is convenient for studying the terahertz characteristics of magnetic fluid and provides technical support for in-depth studies of magnetic fluid.

A multi-directional magnetic field sensor based on tapered few mode fiber and magnetic fluid

A multi-directional magnetic field sensor based on tapered few mode fiber and magnetic fluid is proposed via a single mode fiber (SMF)-tapered few mode fiber (TFMF)-SMF structure. Magnetic fluid (MF) is encapsulated outside the TFMF to detect magnetic fields in different directions. The experimental results show that the change trend of the transmission spectrum is related to the direction of the magnetic field, independent of the length of the taper. When a vertical magnetic field is applied to the sensor, the transmission spectrum is red-shifted with the decrease of the magnetic field intensity. When a parallel magnetic field is applied to the sensor, the transmission spectrum is blue-shifted with the decrease of the magnetic field intensity. For the same sensor, the magnetic field sensitivity in vertical direction is significantly higher than that in parallel direction, and can be up to 70,792.85 pm/Oe by applying a magnetic field direction of 180°. The sensor has the advantages of simple fabrication and high sensitivity, and has a good application prospect in scientific research and other magnetic field measurement.

Structure, dynamics, and morphology of nanostructured water confined between parallel graphene surfaces and in carbon nanotubes by applying magnetic and electric fields.

Water molecules experience certain changes in their properties when they feel an external magnetic or electric field. These changes are significant in different applications, such as biological and biotechnological processes, nano-pumping, and water treatment. In this work, we have performed molecular dynamics (MD) simulations to investigate the different thermodynamics, structure, and dynamics of water molecules confined between two parallel surfaces and also confined in carbon nanotubes (CNTs). We have also applied different electric and magnetic fields in different directions to the confined molecules. In the graphene system, no polygonal shape was formed in either low or high electric fields, whereas rhombic and pentagonal shapes were formed in low and high magnetic fields. In the CNT system, applying electric fields in all three dimensions made the pentagonal shape disappear and the confined water molecules formed a ring shape when the electric field was applied in the axial direction. Applying the electric field perpendicular to the graphene surfaces increases the self-diffusion of the confined molecules, whereas applying the electric and magnetic fields along the CNT axis decreases the self-diffusion of the confined water molecules. In the graphene system, applying the electric field perpendicular to the graphene surfaces decreases the average number of hydrogen bonds (〈HB〉) whereas the magnetic field has little effect on the 〈HB〉. In the CNT system, applying Ex also leads to a smaller number of HBs. Also, applying the magnetic field along the x-direction (along the CNT direction) leads to a greater number of HBs than the other fields.

Nonlinear magnetoelectric effects of multiferroic composites

Magnetoelectric effect is one of the most important features in multiferroic composites which is absent in either ferromagnetic or ferroelectric composites. In this paper, a two-level micromechanics model is developed to study the nonlinear magnetoelectric (ME) effects of multiferroic composites consisting both ferromagnetic (or magneto-strictive) and ferroelectric (or piezoelectric) materials. At the first level, the model involves a thermodynamically based evolution of the product domain from the parent one in ferromagnetic phase which provides the nonlinear response of the system under the external loading. And at the second level, it treats the ferromagnetic and ferroelectric as a two-phase composite, and Eshelby based micromechanics is applied to obtain the overall effective properties of the composite. Then the two-level model is used to study the nonlinear magnetoelectric effects of Terfenol-D/PZT/Terfenol-D laminated system under the applied magnetic field first, and then under the combined mechanical and magnetic field in different directions. To verify the model, the theoretical calculations have been compared with the existing experimental data for both single phase Terfenol-D at the first level and the two-phase Terfenol-D/PZT/Terfenol-D multiferroic composite at the second level. The comparisons between the theory and experiment are in a good agreement.

Numerical simulation of MHD natural convection heat transfer in a square cavity filled with Carreau fluids under magnetic fields in different directions

In this paper, the laminar natural convection of non-Newtonian Carreau fluid in a square cavity under uniform magnetic field in different directions is investigated numerically. Based on the projection method, a new finite-difference algorithm on a staggered grid is employed to solve the laminar magnetohydrodynamic natural convection problems, which involves the second-order central scheme for the discretization of non-Newtonian viscous terms. To assess numerical capability of the newly proposed algorithm, the calculation results for Newtonian fluid in the square cavity show excellent agreement with results available in the literature. Research work has been performed for the certain pertinent parameters of Rayleigh number ( $$10^{4}$$ and $$10^{5}$$ ) and Prandtl number ( $$Pr=0.065$$ ) using the new numerical algorithm. The computed results show that the natural convection of Carreau fluid is not only determined by the strength of the magnetic field, but also influenced by the inclination angle. In particular, when the Carreau fluid describes a non-Newtonian fluid, it is found that the inclination angle plays a large role on flow and heat transfer.

Magneto-optical spin Hall effect of light and its application in refractive index detection

The spin Hall effect of light (SHEL) is a photonic version of the spin Hall effect in electronic systems, and it has been a focused research area in the recent ten years. However, due to the lack of effective methods dynamic modulation of spin-dependent splitting, the practical application of SHEL has remained a challenge, still urgently waiting to be resolved. In recent years, SHEL has been applied to the precise measurement and sensing of various physical quantities. Now, how to make SHEL measurement flexible is the research direction of researchers The magneto-optical spin Hall effect of light (MOSHEL) is a useful attempt to implement a dynamic transformation of SHEL. The spin–orbit coupling or non-reciprocal phase shift caused by magnetic fields in different directions applied to magneto-optical materials can be flexibly and timely controlled. This paper reports our studies on the magneto-optical effect in multilayer structure. For the first time, the refractive index of very low concentration sample solution is sensed through the method of weak measurement under the condition of transverse magneto-optical Kerr effect. The ultra-high sensitivity of 2.9×104μm/RIU was measured under the optimum parameters. This is of great significance in advancing the practical application of MOSHEL.

Magnetic field controlled hybrid semiconductor and resistive switching device for non-volatile memory applications

A magnetic-field-controlled non-volatile memory device is fabricated by coupling Hall effect and resistive switching effect. The non-volatile property of the device is due to the fact that the Hall voltage of the semiconductor changes the resistance state of the resistive switching unit. By changing the device configuration, the storage can be controlled by magnetic fields in different directions. The parameters of the semiconductors and the resistive switching units are experimentally investigated and simulated to optimize the performance of the devices. The key to increasing the ON/OFF ratio and reducing power consumption is finding a suitable resistance match between the semiconductor and the resistive switching unit. By enhancing the mobility of the semiconductor, the performance of the device can also be significantly improved. This hybrid device provides new insights into the manufacture of magnetic field controlled non-volatile memory devices with potential of integrating computing and storage functions.

Absorption and quantum coherence of a degenerate two-level system in the presence of a transverse magnetic field in different directions

We investigate the absorption spectra for the ${F}_{g}=1\ensuremath{\rightarrow}{F}_{e}=0$ transition of the ${D}_{2}$ line of $^{87}\mathrm{Rb}$ excited by a linearly polarized light in the presence of a transverse magnetic field (TMF) in different directions. Using the theoretical methods in quantum optics, we obtain the analytical expressions for the atomic density-matrix elements and the absorption spectrum. We analyze the splitting proportional to the magnitude of the TMF in the coherent population trapping absorption spectrum and explain its physical origin. Then, the sensitivity of the resonance signal to the phase (in our case, to the angle between the TMF and the light polarization) is investigated. We show and explain the splitting of the bright resonance and find the simple dependence of the separation of this splitting on the magnitude and the direction of the TMF. Therefore, this system may provide a possible method for the measurement of the magnetic field vector. In addition, we study the coherence of the system based on an observable coherence measure, namely, robustness of coherence (ROC). We find that in the case where the absorption signal becomes difficult to detect, the change of the ROC spectrum becomes more obvious and the extreme points are well maintained. Therefore, this may provide a scheme for the measurement of the magnetic field which is complementary to that based on the absorption signal of the laser.

The effect of external magnetic field on the linear stage evolution of Kelvin–Helmholtz instability in laser driven plasma

A Kelvin–Helmholtz instability (KHI) is a fundamental physical process of fluids and magnetized plasma. We report the experimental formation of a KHI produced by intense laser-driven thin plastic foils. For an external magnetic field in different directions, the KHI shows different evolutionary features. A theoretical derivation shows that an external magnetic field has a stronger effect on KHI growth when its component is perpendicular to the plasma flow. A linear evolutionary stage of the KHI is captured by optimizing the target design, which is reproduced by FLASH simulation.

Zebrafish “personality” influences sensitivity to magnetic fields

How animals integrate different sensory information for orientation is a complex process involving interactions between a variety of internal and external factors. Due to this complexity, each component of a suite of factors is typically studied in isolation. Here, we examine how an internal factor (personality of fish) influences the response of zebrafish (Danio rerio) to the magnetic field, while swimming in a flow chamber. Our previous work demonstrated that the orientation to the water current (rheotaxis) of zebrafish individuals is influenced by variations of the magnetic field only when fish are part of a shoal. In this study, we evaluated the rheotactic behavior of 20 fish, grouped in shoals of “proactive” or “reactive” individuals, under magnetic fields of different directions. We found that the magnetic field influenced at which water speed rheotaxis was elicited in zebrafish with “reactive” personality, but not in those with “proactive” personality. These results suggest that fish personality influences response to or weighing of sensory inputs and provides some insight on the variation in behavioral responses to environmental stimuli in both laboratory and natural settings.

Compensation for Magnetic Disturbances in Motion Estimation to Provide Feedback to Wearable Robotic Systems.

The direction of the Earth's magnetic field is used as a reference vector to determine the heading in orientation estimation with wearable sensors. However, the magnetic field strength is weak and can be easily disturbed in the vicinity of ferromagnetic materials, which may result in inaccurate estimate of orientation. This paper presents a novel method for estimating and compensating for magnetic disturbances. The compensation algorithm is implemented within a kinematic-based extended Kalman filter and is based on an assessment of the magnetic disturbance and the change of orientation in each time step. The proposed algorithm was experimentally validated by measuring the orientation of a simple mechanical system with three degrees of freedom in an artificially disturbed magnetic field. The results of the experimental evaluation show that an Kalman filter algorithm that incorporates compensating for magnetic disturbances is capable of estimating the orientation with moderate error (the absolute median errors , ) when the Earth's magnetic field is disturbed by magnetic disturbance with a magnitude equal to twice the magnitude of the Earth's own magnetic field in different directions.

Simulation of the influence of constant uniform magnetic field on a miniature LIT mass spectrometer.

In this paper, the effects of constant uniform magnetic fields on a miniature linear ion trap mass spectrometer with hyperbolic electrodes are simulated using SIMION 8.0 3D software. Magnetic fields in different directions have different effects on the trajectories of the trapped ions and the shape of the ion cloud. When the magnetic field is applied in the z-direction, namely the ion injection direction, the magnetic field will cause the ions focusing to the z-axis, and exert a compression effect on the ion cloud. When the magnetic field is applied in the x-y plane, the original ion cloud will be expanded due to the action of the applied magnetic field, and the ion cloud plane after expansion is always perpendicular to the direction of the magnetic field. The discovery of influence field of magnetic will bring some useful inspiration for the improvement of ion trapping efficiency, mass resolution, sensitivity and trapping capacity, which is conductive to the performance enhancement utilization of magnetic field, even in the industrial application development and other aspects.

LBM-IBM-DEM modelling of magnetic particles in a fluid

A lattice Boltzmann method-immersed boundary method-discrete element method (LBM-IBM-DEM) scheme was presented to simulate the behavior of magnetic particles in a fluid with external magnetic field. In the present scheme, the flow field was solved by the LBM, the DEM with the consideration of the magnetic force was used to describe the particle behavior and the flow field was computed by the momentum exchange-based IBM. Numerical simulations of fluid-particle interactions with uniform magnetic fields in different directions (vertical magnetic field and transverse magnetic field) were carried out to study the particle motion and hydrodynamic behavior in details. The numerical results indicated that the external magnetic force has a significant influence on the particle behavior, where some fragmented chains along the direction are formed and these chain-like clusters continue to lengthen, align, and approach an almost steady state. In addition, we also studied the effect of the magnetic field strength on the motion of magnetic particles showing that in the same particle system, stronger magnetic field brings magnetic particles greater kinetic energy than the low density magnetic field does.