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Suppression of 1/f noise in tunnel magnetoresistance (TMR) sensors is a central issue in the realization of magnetic field sensors with ultrafine magnetic field detectivity. Although AC modulation with an external magnetic field has been proposed as a method to shift the operating frequency of a sensor to a high frequency and substantially suppress 1/f noise, its effects on the two types of 1/f noise, that is, magnetic and electrical 1/f noise, are not well understood. In this study, we investigated the noise characteristics and signal detection performance of TMR sensors with an even-function resistance-magnetic field curve operated by the AC modulation method. For one TMR device in which the magnetic 1/f noise was dominant, AC modulation degraded the magnetic field detectivity owing to the additional noise induced by the AC modulation field. However, in another TMR device, in which the electrical 1/f noise was artificially enhanced by introducing lattice defects in the MgO tunnel barrier, AC modulation effectively suppressed the 1/f noise and improved the magnetic field detectivity by one order. This demonstrates that the AC modulation method using an external magnetic field is effective for magnetic field sensors in which electrical 1/f noise is dominant. [ABSTRACT FROM AUTHOR]

We investigated the thermal stability and performance of AlGaN/AlN/GaN Hall-effect sensors under industry-relevant atmospheric conditions. The thermal stability and performance of Hall sensors are evaluated by monitoring Hall sensitivity, two-dimensional electron gas density, and Ohmic contact resistance during aging at 200 °C for up to 2800 h under atmospheric conditions. This was accomplished by characterizing AlGaN/AlN/GaN micro-Hall sensors, with and without contacts, and before and after being placed under different thermal aging times. Observed electrical performance was correlated with the micro-structural evolution of AlGaN/AlN/GaN Hall sensor heterostructures. Results indicate that the AlGaN/AlN/GaN Hall sensor provides stable performance for as long as 2800 h aging at 200 °C without any significant degradation of (i) Hall sensitivity, (ii) two-dimensional electron gas, and (iii) Ohmic contacts. However, there was a small change in sheet density and mobility, which is due to a decrease in polarization, resulting from local inhomogeneous strain relief at the barrier layer. During the early stage of thermal aging, a decrease in contact resistance was also observed and attributed to (i) out-diffusion of "Ga" at the vicinity of the contact interface, and (ii) a reduction in oxygen concentration and formation of Al–Ti intermediate alloy at the GaN/Ti interface, resulting in a reduced barrier and enhanced electron transport at the contacts. However, despite these small changes, results indicate that the AlGaN/AlN/GaN Hall sensor provides stable performance for as long as 2800 h thermal aging at 200 °C. [ABSTRACT FROM AUTHOR]

Drone‐based geophysical surveying is an emerging measuring platform. High time‐cost efficiency and flexibility to survey over inaccessible areas make drones attractive or sometimes the only feasible option to carry geophysical measurements. This study presents a new drone‐towed electromagnetic induction and magnetic gradient sensor system used for near‐surface characterization and areal mapping. The system uses various datasets to enhance processing and interpretation. The system includes; an electromagnetic induction instrument; magnetic sensors; GNSS‐IMU system; photogrammetry; Lidar model data; and geoid model data. Robust data processing and stochastic inversion subsurface characterization for archaeological prospecting with drone‐towed electromagnetic induction and magnetic gradient sensor systems. Robust statistical methods were used to process the data. We conducted the fieldwork at one of the ancient Viking settlements in Denmark. The surveyed area was approximately 100×$\times$200 m. We then implemented and applied a one‐dimensional laterally constrained non‐linear stochastic inversion to image the subsurface electrical conductivity. The inversion results show a consistent conductive layer at 5–8 m depths, likely associated with the groundwater level. This conductive layer is disrupted under a prominent anomaly within a 2–4 m wide area. Our analysis showed that this conductivity disruption could be a flint mine extending 7 m deep. This anomaly also has a strong signature in magnetic gradient data. [ABSTRACT FROM AUTHOR]

Modern power system protection schemes incorporate artificial intelligence (AI) techniques. However, in a conventional way, most of these schemes rely on the data of current and voltage collected from current transformer (CT) and potential transformer (PT) respectively. CTs suffer from the drawback of core saturation and impact the accuracy and effectiveness of intelligent methods. Also, it has the constraints of size, safety, and economy. The research here explores the effectiveness of magnetic sensors in advanced power system protection schemes as an alternative to traditional current sensing. In the presented work, a novel dataset is prepared by transforming transmission line currents into magnetic field components. Several supervised as well as unsupervised machine learning algorithms have been applied to this data instead of traditional currents and voltage for fault prediction. The paper discusses the comparative evaluation of these algorithms based on various performance metrices which reveals that Gaussian Naïve Bayes (GNB), K-nearest neighbor (KNN), random forest (RF), and extreme gradient boost (XGB) algorithms excel in fault detection, while multilayer perceptron (MLP) and KNN performs better fault classification. The findings promise the potential for developing compact, safe, and cost-effective protection schemes utilizing magnetic field sensors. [ABSTRACT FROM AUTHOR]

Magnetoelectric (ME) antennas hold the potential for significantly advancing miniaturization in radio frequency devices due to their compact size. However, critical hurdles still remain in ME antennas including low radiation efficiency and narrow bandwidth, which prevent them from seeing widespread use. Here, by sweeping the magnetic field to reach a resonant coupling, a significant enhancement in radiation efficiency by 70.95 ± 6.4% in a broad bandwidth ME antenna with 80 MHz is achieved as well as the far‐field radiation patterns are changed compared with that via non‐resonant coupling. The enhancement depends on the relative orientation between the magnetization and surface acoustic wave propagation direction which is dominated by the symmetry of the driving field induced by shear strain. A larger enhancement occurs when the magnetic field along hard axis of Ni due to the matching helicity and larger strain compared with easy axis scenario. This work demonstrates an innovative methodology that significantly enhances the radiation and reception efficiency in ME antennas, which may provide ideas for subsequent applications in communication antennas and magnetic sensors. [ABSTRACT FROM AUTHOR]

• ELF response to large-scale transmitter ZEVS has been detected by satellite CSES. • CSES sensors detected narrowband 82 Hz emission with amplitudes E∼2 μV/m and B∼0.5 pT. • Wave spatial structure excited by 82 Hz horizontal 60 km current has been modeled. • Modeling shows that CSES recorded response corresponds to transmitter current >100 A. The extremely-low-frequency (ELF) response in the upper ionosphere to ground large-scale transmitter ZEVS on the Kola Peninsula has been detected by low-Earth orbiting satellite CSES (∼ 500 km altitude). When the satellite was in the vicinity of the ZEVS transmitter above the White Sea (horizontal distance ∼ 400–900 km), the electric and magnetic sensors detected a narrowband 82 Hz emission with amplitudes E ≃ 1 - 3 μ V/m and B ≃ 0.5 - 1.0 pT. We modeled the ELF wave field spatial structure in the upper ionosphere excited by an oscillating 82 Hz linear current with the 60 km length suspended above a high-resistive ground. Realistic altitudinal profiles of the plasma parameters during events under study have been reconstructed with the use of the IRI ionospheric model. The modeled amplitudes of electromagnetic response of the upper ionosphere are in reasonable agreement with the 82-Hz emission power recorded by the CSES satellite for a typical transmitter current intensity > 100 A. [ABSTRACT FROM AUTHOR]

Motion analysis is of great interest to a variety of applications, such as virtual and augmented reality and medical diagnostics. Hand movement tracking systems, in particular, are used as a human–machine interface. In most cases, these systems are based on optical or acceleration/angular speed sensors. These technologies are already well researched and used in commercial systems. In special applications, it can be advantageous to use magnetic sensors to supplement an existing system or even replace the existing sensors. The core of a motion tracking system is a localization unit. The relatively complex localization algorithms present a problem in magnetic systems, leading to a relatively large computational complexity. In this paper, a new approach for pose estimation of a kinematic chain is presented. The new algorithm is based on spatially rotating magnetic dipole sources. A spatial feature is extracted from the sensor signal, the dipole direction in which the maximum magnitude value is detected at the sensor. This is introduced as the "maximum vector". A relationship between this feature, the location vector (pointing from the magnetic source to the sensor position) and the sensor orientation is derived and subsequently exploited. By modelling the hand as a kinematic chain, the posture of the chain can be described in two ways: the knowledge about the magnetic correlations and the structure of the kinematic chain. Both are bundled in an iterative algorithm with very low complexity. The algorithm was implemented in a real-time framework and evaluated in a simulation and first laboratory tests. In tests without movement, it could be shown that there was no significant deviation between the simulated and estimated poses. In tests with periodic movements, an error in the range of 1° was found. Of particular interest here is the required computing power. This was evaluated in terms of the required computing operations and the required computing time. Initial analyses have shown that a computing time of 3 μ s per joint is required on a personal computer. Lastly, the first laboratory tests basically prove the functionality of the proposed methodology. [ABSTRACT FROM AUTHOR]

The rise of the metaverse concept has brought about widespread attention in wearable gesture recognition devices. Data gloves based on flexible strain sensors have been favoured by researchers owing to their low cost, light weight, direct and continuous monitoring of finger movements. In this review, we first compare the advantages and disadvantages of four different approaches based on the vision sensors, myoelectric sensors, inertial and magnetic sensors, and flexible strain sensors in designing data gloves, and demonstrate the superiority of the flexible strain sensor-based data glove used for metaverse applications. Next, some latest commercial data gloves are exampled and the function modules of the data gloves are presented based on the flexible strain sensors. Meanwhile, the potential applications of gesture recognition in the metaverse are summarized in diversified fields. Finally, the existing problems and development prospects of the current data gloves based on flexible strain sensors are concluded. We are optimistic that novel flexible strain sensor-based data gloves will make transformational impact to realize accurate, low-latency, and immersive gesture interaction in the metaverse. [ABSTRACT FROM AUTHOR]

In this study, we employed a high‐frequency‐driven thin‐film magnetic sensor to precisely measure the magnetic near field with enhanced spatial resolution, a challenge often faced by conventional loop antennas. Our study introduced an innovative approach utilizing this magnetic sensor to assess the magnetic near field in wireless power transfer systems, comparing its performance against that of a loop antenna. Our findings demonstrate that the magnetic sensor achieves its peak signal‐to‐noise ratio at a DC bias field of 4.7 Oe and carrier frequency of 0.5 GHz, boasting a detection limit for magnetic fields of ~0.4 A/m. Moreover, the magnetic field trend measured by the magnetic sensor closely aligns with simulation results, exhibiting sharper changes around the center compared to the loop antenna. These results highlight the superior sensitivity and spatial resolution of the magnetic sensor over conventional loop antennas. By enhancing the reliability of electronic systems across diverse applications, these sensors pave the way for advanced EMI/EMC evaluation techniques. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In this study, we focus on human activity recognition, particularly aiming to distinguish the activity of praying (salat) from other daily activities. To achieve this goal, we have created a new dataset named HAR-P (Human activity recognition for Praying), which includes eight different activities: walking, running, sitting, standing, walking upstairs, walking downstairs, typing with a keyboard, and praying (salat). The HAR-P dataset was collected from 50 male individuals, who wore smartwatches on their dominant wrists. We compare the activity classification performance using three state-of-the-art algorithms from the literature: Long Short-Term Memory, Convolutional Long Short-Term Memory, and Convolutional Neural Network—Long Short-Term Memory. To assess the influence of sensors, data from accelerometer, gyroscope, linear acceleration sensor, and magnetic field sensor were utilized. The impact of individual sensor data as well as combinations thereof was investigated. The highest classification accuracy within single sensor groups, reaching 95.7%, was achieved using the accelerometer data with the Convolutional Long Short-Term Memory method. Combining two sensor groups resulted in an increase in accuracy of up to 9%. The highest accuracy of 96.4% was obtained by utilizing three sensor groups together with the Convolutional Neural Network—Long Short-Term Memory method. Furthermore, the evaluation of sensor and model performance was conducted using the stratified k-fold cross-validation method with 5-folds. These findings contribute significantly to evaluating the performance of sensor combinations and different algorithms in activity classification. This study may provide an effective foundation for the automatic recognition and tracking of human activities and offer an applicable model, particularly for the recognition of religious practices such as praying. [ABSTRACT FROM AUTHOR]

Copyright of Progress in Earthquake Sciences is the property of China Earthquake Administration, Institute of Geophysics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Atomic magnetometers (AMs) that use alkali vapors, such as rubidium, are among the most sensitive sensors for magnetic field measurement. They commonly use polarization differential detection to mitigate common-mode noise. Nevertheless, traditional differential detection optics, including polarization beam splitters (PBS) and half-wave plates, are typically bulky and large, which restricts further reductions in sensor dimensions. In this study, a combination of liquid crystal polarization grating (LCPG) and liquid crystal quarter-wave plate is used for differential detection in AMs, with magnetic field strength determined by measuring the intensity of two diffracted beams from the LCPG. The experimental findings indicate that the fabricated LCPG exhibits a circularly polarized extinction ratio of 3,656 and achieves an average diffraction efficiency of 99 %. In addition, the differential detection method based on LCPG can achieve an angular resolution of 1.48 × 10−7 rad. Subsequently, the method is employed in an AM to achieve an average magnetic sensitivity of 13.8 fT/Hz1/2. Compared to the PBS-based differential detection method, this method enhances the magnetometer response coefficient by 13 % and achieves co-side distribution of the two diffracted beams, thereby avoiding the need for additional vertical optical paths. The effective thickness of the detection optics is reduced to the micrometer scale, allowing for future integration as thin films onto microfabricated vapor cells. This study offers a practical solution for miniaturized AMs with exceptionally high sensitivity. [ABSTRACT FROM AUTHOR]

Magnetic stabilization of the ferromagnetic layers of magnetoresistive elements is a key technological requirement for fabricating highly sensitive and accurate magnetic sensors. Here, we report on a tunnel magnetoresistive (TMR) sensor wherein the free layer (FL) magnetization is stabilized by combining exchange bias, noncollinear interlayer exchange coupling through a RuFe spacer, and orange-peel ferromagnetic coupling. This method facilitates stabilization of the FL magnetization over a wide range of noncollinear angles with respect to the pinning direction by controlling the composition of the RuFe spacer. Moreover, the uniaxial anisotropy induced in the FL by annealing plays an important role in the resistance–magnetic field (R–H) curve, which was studied both experimentally and through simulation. The TMR devices exhibited negligible hysteresis even in the major R–H loops, which is promising for magnetic field-sensing applications. [ABSTRACT FROM AUTHOR]

The rapid development of ocean exploration and underwater robot technology has put forward new requirements for underwater sensing methods, which can be used for hydrodynamic characteristics perception, underwater target tracking, and even underwater cluster communication. Here, inspired by the specialized undulated surface structure of the seal whisker and its ability to suppress vortex‐induced vibration, a multidirectional hydrodynamic sensor based on biomimetic whisker array structure and magnetic 3D self‐decoupling theory is introduced. The magnetic‐based sensing method enables wireless connectivity between the magnetic functional structures and electronics, simplifying device design and endowing complete watertightness. The 3D self‐decoupling capability enables the sensor, like a seal or other organisms, to perceive arbitrary whisker motions caused by the action of water flow without complex calibration and additional sensing units. The whisker sensor is capable of detecting a variety of hydrodynamic information, including the velocity (RMSE < 0.061 m s−1) and direction of the steady flow field, the frequency (error < 0.05 Hz) of the dynamic vortex wake, and the orientation (error < 7°) of the vortex wake source, demonstrating its extensive potential for underwater environmental perception and communication, especially in deep sea conditions. [ABSTRACT FROM AUTHOR]

Flexible electronic devices extended abilities of humans to perceive their environment conveniently and comfortably. Among them, flexible magnetic field sensors are crucial to detect changes in the external magnetic field. State‐of‐the‐art flexible magnetoelectronics do not exhibit low detection limit and large working range simultaneously, which limits their application potential. Herein, a flexible magnetic field sensor possessing a low detection limit of 22 nT and wide sensing range from 22 nT up to 400 mT is reported. With the detection range of seven orders of magnitude in magnetic field sensor constitutes at least one order of magnitude improvement over current flexible magnetic field sensor technologies. The sensor is designed as a cantilever beam structure accommodating a flexible permanent magnetic composite and an amorphous magnetic wire enabling sensitivity to low magnetic fields. To detect high fields, the anisotropy of the giant magnetoimpedance effect of amorphous magnetic wires to the magnetic field direction is explored. Benefiting from mechanical flexibility of sensor and its broad detection range, its application potential for smart wearables targeting geomagnetic navigation, touchless interactivity, rehabilitation appliances, and safety interfaces providing warnings of exposure to high magnetic fields are explored. [ABSTRACT FROM AUTHOR]

Detection of ultralow magnetic field requires a magnetic sensor with high sensitivity and a low noise level. In this work, we used the Co20Fe60B20/Ti/Co20Fe60B20 magnetically coupled multilayer as the core structure of an anomalous Hall sensor. We adjusted the thickness of the Ti interlayer to modify its perpendicular magnetic anisotropy and interlayer magnetic coupling, thereby improving the sensitivity of the anomalous Hall sensor. Through the investigation of magnetic field response and noise properties of devices with different Ti thicknesses, the highest sensitivity of 34 803 Ω/T and the best magnetic field detectivity of 4.6 nT/ Hz at 1 Hz were achieved with a Ti thickness of 2.0 nm at room temperature. This anomalous Hall sensor has both ultrahigh sensitivity and magnetic field detectivity, making it a good candidate for applications in detecting weak magnetic fields. [ABSTRACT FROM AUTHOR]

Optical and magnetic sensing methods are integral to both research and clinical applications in biological laboratories. The ongoing miniaturization of these sensors has paved the way for the development of point-of-care (PoC) diagnostics and handheld sensing devices, which are crucial for timely and efficient healthcare delivery. Among the various competing sensing and circuit technologies, CMOS (complementary metal–oxide–semiconductor) stands out due to its distinct cost-effectiveness, scalability, and high precision. By leveraging the inherent advantages of CMOS technology, recent developments in optical and magnetic biosensors have significantly advanced their application in life sciences, offering improved sensitivity, integration capabilities, and reduced power consumption. This paper provides a comprehensive review of recent advancements, focusing on innovations in CMOS-based optical and magnetic sensors and their transformative impact on biomedical research and diagnostics. [ABSTRACT FROM AUTHOR]

A high sensitivity photonic crystal fiber (PCF) magnetic field sensor based on Sagnac interferometer is proposed. All the air holes of the PCF are completely filled with the magnetic fluid (MF), which is a magnetic liquid material. The sensing performance of PCF is simulated and analyzed by using finite element method (FEM). It is found that the effects of wavelength λ, phase birefringence B(λ,H), and group birefringence Bg(λ,H) on the sensitivity are very significant. The two dip points in this spectrum show a red shift and a blue shift as the refractive index of the magnetic fluid increases, respectively. This magnetic field sensor obtains the average sensitivity of 889.5 pm/Oe (111,684.9 nm/RIU) and −994.3 pm/Oe (−124,839.5 nm/RIU) in the range from 90 to 240 Oe. [ABSTRACT FROM AUTHOR]

This paper presents a small size and high-integration inductive displacement sensor used for magnetic bearings. This sensor is a circular ring structure fixed on radial direction of a magnetic bearing and can measure radial and axial displacement at the same time. Sensitivity results show that displacement detection along each direction will not be affected by others. Then, the proposed sensor is applied in closed-loop control of a magnetic bearing when the rotor is levitated and rotates at 40k, 50k, and 60k r/min. According to experiment results, radial and axial displacement vibrate noise can be controlled within ±10 μm and about ±10 μm, respectively, evaluating the feasibility of inductive displacement sensor in closed-loop control. Contribution of this paper is to explore application boundary and provide a guide of applicable speed for inductive displacement sensor, which will help to promote application of magnetic bearing in more fields. And based on the experiment results present in this paper, inductance sensor can be used for magnetic bearing control when the rotation speed is below 60k r/min. [ABSTRACT FROM AUTHOR]

Tactile sensing in the human body is achieved via the skin. This has inspired the fabrication of synthetic skins with pressure sensors for potential applications in robotics, bio‐medicine, and human–machine interfaces. Tactile sensors based on magnetic elements are promising as they provide high sensitivity and a wide dynamic range. However, current magnetic tactile sensors mostly detect pressures of solid objects and operate at relatively high forces about 100 mN. Herein, these limitations are addressed by manufacturing soft, stretchable, and hair‐like structures that are permanently magnetized to achieve high‐resolution, cost‐effective, and high‐resolution pressure sensing. Combining these hair‐like structures with advances in 3D magnetic‐field measurements allows us to monitor directional tactile pressures without solid contact. To prove the concept of this technology, a bio‐inspired soft device is built with a hairy structure that senses and reports environmental mechanical stresses, similar to that of human skin. Simple self‐assembly of the soft magnetic hair structure makes our approach easy to scale for large‐area applications. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We implement a distributed Bragg reflector (DBR) laser diode (LD) package with low-magnetic field generation. The package consists of a commercial 795 nm DBR LD chip, a thermo-electric cooler (TEC), a thermistor, a flexible printed circuit board (FPCB) which cancels the magnetic field emitted by the TEC current flow, and a non-magnetic aluminum case. We confirm that the magnetic dipole moment of our low-magnetic package body is about three orders of magnitude smaller than that of a commercial DBR laser package. Moreover, it is shown that our compensating FPCB, the effectiveness of which is supported by computer simulations, reduces the magnetic field magnitude by a factor of 2.2. The FPCB also reduces the magnetic field gradient emitted by the TEC current flow so that gradient-induced spin relaxations are suppressed in applications. A portable optically pumped atomic magnetometer (OPAM) utilizing two low-magnetic packages as light sources is reported as an application of the package and shows a 0.30 pT/Hz1/2 level magnetic sensitivity at a 69 μT external magnetic field; in contrast, the OPAM utilizing the commercial packages showed a magnetic sensitivity of 0.87 pT/Hz1/2. [ABSTRACT FROM AUTHOR]

Negatively charged silicon vacancy (VSi−) defects in silicon carbide are expected to be used for magnetic sensors under harsh environments, such as space and underground due to their structural stability and potential for high-fidelity spin manipulation at high temperatures. To realize VSi− based magnetic sensors operating at high temperatures, the temperature dependence of optically detected magnetic resonance (ODMR) in the ground states of VSi− defects, which is the basic principle of magnetic sensing, should be systematically understood. In this work, we demonstrate the potential of VSi− magnetic sensors up to at least 591 K by showing the ODMR spectra with different temperatures. Furthermore, the resonance frequency of the ground level was independent of temperature, indicating the potential for calibration-free magnetic sensors in temperature-varying environments. We also characterize the concentration of VSi− defects formed by electron irradiation and clarify the relationship of magnetic sensing sensitivity to VSi− concentration and find that the sensing sensitivity increases linearly with VSi− concentration up to at least 6.0 × 1016 cm−3. The magnetic sensitivity at a temperature above 549 K was reduced by half as compared to that at 300 K. The results pave the way for the use of a highly sensitive VSi−-based magnetic sensor under harsh environments. [ABSTRACT FROM AUTHOR]

Introduction. Methods of automatic measurement of rail track joint gaps are not accurate enough or require costly equipment and sensors. This is why joint gaps are still monitored manually in many cases. The work is intended to experiment and examine a new method of automatic measurement of gaps in bolted rail joints using magnetic flaw detection (MFL).Materials and methods. The paper uses actual track inspection results obtained by a flaw detection car on one of the railroads of Russian Railways. A specially developed programme used magnetic channel signals to highlight bolted rail joint locations and determine the magnitude of the joint gaps. The joint gaps were also measured manually using video images of bolted joints obtained by the on-board rail video recording system.Results. The authors obtained expressions for calculating the joint gap value using magnetic sensor signals. Small gaps (up to 8 mm) are estimated by amplitude, medium and large gaps (above 9 mm) — by the spatial parameter of the signals from joint gaps. The authors compared the gap measurements from the two specified methods: visual and magnetic.Discussion and conclusion. The research confirmed that automatic identification of bolted joints and determination of the value of joint gaps by magnetic rail flaw detection are sufficiently reliable for practical application. A comparative analysis of the values of the video inspection and the magnetic method showed high accuracy of joint gap measurement when using the latter. The magnetic method signals show high stability and repeatability.

Mechanotransduction is the essential process that cells convert mechanical force into biochemical responses, and electrochemical sensor stands out from existing techniques by providing quantitative and real-time information about the biochemical signals during cellular mechanotransduction. However, the intracellular biochemical response evoked by mechanical force has been poorly monitored. In this paper, we report a method to apply local stretch on single cell and simultaneously monitor the ensuing intracellular biochemical signals. Specifically, a ferromagnetic micropipette was fabricated to locally stretch a single cell labeled with Fe3O4 nanoparticles under the external magnetic field, and the SiC@Pt nanowire electrode (SiC@Pt NWE) was inserted into the cell to monitor the intracellular hydrogen peroxide (H2O2) production induced by the local stretch. As a proof of concept, this work quantitatively investigated the elevated amount of H2O2 levels in single endothelial cell under different stretching amplitudes. This work puts forward a new research modality to manipulate and monitor the mechanotransduction at the single-cell level. [ABSTRACT FROM AUTHOR]

Differential coils are frequently implemented in inductive sensing systems. They can be considered as a single coil that is made up of two or more subcoils, wound in series opposition. They can be used on the transmit or receive side of measurement systems, and, if designed correctly, ensure no coupling between coils under background conditions. By cancelling background coupling, the receive electronics only needs to be able to measure the change in coupling produced by a target. This allows for a more efficient use of the dynamic range, and for larger receive-side amplifier gain, thereby improving SNR. When subcoils are not electrically similar, it can be hard to engineer the coil to be perfectly balanced across a wide bandwidth. This paper presents an analytical model of a resonant differential coil pair that is tested and applied on a planar metal detector for the detection of buried objects. The model demonstrates the capability to balance an arbitrary differential coil pair, which has a broad applicability across a range of inductive sensor applications such as metal detection and non-destructive testing. The method is applied to the practical system. The results show that the correction resulting from this method ensures a stable balance across a significantly enhanced bandwidth. In the case studied here, the bandwidth of the experimental system is increased from 20 kHz to 90 kHz. [ABSTRACT FROM AUTHOR]

Magnetic pose tracking is a non-contact, accurate, and occlusion-free method that has been increasingly employed to track intra-corporeal medical devices such as endoscopes in computer-assisted medical interventions. In magnetic pose-tracking systems, a nonlinear estimation algorithm is needed to recover the pose information from magnetic measurements. In existing pose estimation algorithms such as the extended Kalman filter (EKF), the 3-DoF orientation in the S 3 manifold is normally parametrized as unit quaternions and simply treated as a vector in the Euclidean space, which causes a violation of the unity constraint of quaternions and reduces pose tracking accuracy. In this paper, a pose estimation algorithm based on the error-state Kalman filter (ESKF) is proposed to improve the accuracy and robustness of electromagnetic tracking systems. The proposed system consists of three electromagnetic coils for magnetic field generation and a tri-axial magnetic sensor attached to the target object for field measurement. A strategy of sequential coil excitation is developed to separate the magnetic fields from different coils and reject magnetic disturbances. Simulation and experiments are conducted to evaluate the pose tracking performance of the proposed ESKF algorithm, which is also compared with standard EKF and constrained EKF. It is shown that the ESKF can effectively maintain the quaternion unity and thus achieve a better tracking accuracy, i.e., a Euclidean position error of 2.23 mm and an average orientation angle error of 0.45°. The disturbance rejection performance of the electromagnetic tracking system is also experimentally validated. [ABSTRACT FROM AUTHOR]

The high-precision magnetic survey system is crucial for ocean exploration. However, most existing systems face challenges such as high noise levels, low sensitivity, and inadequate magnetic compensation effects. To address these issues, we developed a high-precision magnetic survey system based on the manned submersible "Deep Sea Warrior" for deep-ocean magnetic exploration. This system incorporates a compact optically pumped cesium (Cs) magnetometer sensor to measure the total strength of the external magnetic field. Additionally, a magnetic compensation sensor is included at the front end to measure real-time attitude changes of the platform. The measured data are then transmitted to a magnetic signal processor, where an algorithm compensates for the platform's magnetic interference. We also designed a deep pressure chamber to allow for a maximum working depth of 4500 m. Experiments conducted in both indoor and field environments verified the performance of the proposed magnetic survey system. The results showed that the system's sensitivity is ≤0.5 nT, the noise level of the magnetometer sensor is ≤1 pT/√Hz at 1 Hz, and the sampling rate is 10 Hz. The proposed system has potential applications in ocean and geophysical exploration. [ABSTRACT FROM AUTHOR]

The magnetoelectric (ME) sensor is a new and promising type of magnetic field sensor with ultrahigh sensitivity. However, there are few reports on the research of real‐time measurement system which can promote its practical application. Herein, a novel real‐time measuring approach for weak AC magnetic fields at relatively low frequency is proposed using Metglas/PZT‐5B ME sensors. The system mainly consists of an oscilloscope, a signal generator, and a program developed with LabVIEW programming. Real‐time measurement of relatively low‐frequency magnetic fields has been achieved by using frequency upconversion methods, simultaneously displaying the frequency and magnitude of the magnetic field. As a result, the real‐time measurement system is able to detect a weak AC magnetic field as low as 0.1 nT@1 Hz, which is promising to push the ME sensor to practical application. [ABSTRACT FROM AUTHOR]

Noninvasive imaging of circuit breakers under short-circuit testing is addressed by recording the magnetic field produced over an array of external sensors and by solving an inverse problem to identify the causing current distribution. The temporal and spatial resolution of the sensing chain are studied and implemented in a physical set-up. A wire model is adopted to describe electrical current distribution. Additionally, the simpler, more direct approach to evaluating the passage of electric current in front of sensors is proposed. The dynamics of suitable approximating models of the electric arc that forms across contacts is obtained and agrees with multi-physical simulations and with experimental time histories of current and voltage. The two methods are flexible and allow the analysis of different types of circuit breakers. [ABSTRACT FROM AUTHOR]

Non-toroidal-shaped primary pass-through protection current transformers (CTs) are used to measure high currents. Their design provides them with a big airgap that allow the passing of several cables per phase though them, which is the main advantage versus toroidal types, as the number of CTs required to measure the whole phase current is drastically reduced. The cables passed through the transformer window can be in several positions. As the isolines of the magnetic field generated by the primary currents are centered in the cables, if these cables are not centered in the transformer window, then the magnetic field will be non-uniform along the transformer core. Consequently, local saturations can appear if the cables are not properly disposed, causing the malfunction of the CT. In this paper, the performance of a non-toroidal-shaped protection CT is studied. This research is focused on the influence of the cable position on possible partial saturations of the CT when it is operating near to its accuracy limit. Depending on the cable position, the ratio of the primary and secondary currents can depart from the assigned ratio. The validation of this phenomenon was carried out via finite element analysis (FEA), showing that partial transformer core saturations appear in areas of the magnetic core close to the cable. By applying FEA, the admissible accuracy region for cable positioning inside the CT is also delimited. Finally, the simulation results are ratified with experimental tests performed in non-toroidal protection CTs, varying the primary cables' positions, which are subjected to currents up to 5 kA, achieving satisfactory results. From this analysis, installation recommendations are given. [ABSTRACT FROM AUTHOR]

In this work, a current and magnetic field sensor is proposed and experimentally demonstrated utilizing a fiber-optic Mach–Zehnder interferometer (MZI) structure. In our setup, one of the interferometer arms is coated with magnetic nanoparticles. The MZI comprises a laser source emitting an optical signal, split by a coupler into two signals propagated by a reference fiber and a sensor fiber. The sensing fiber is encased in cobalt ferrite (CoFe2O4). Upon exposure to a magnetic field, CoFe2O4 induces vibration in the fiber, modifying the sensor's transmission and causing an imbalance between the optical signals of the interferometer arms. This enables us to evaluate the sensor performance regarding sensitivity, accuracy, and saturation. The nanoparticles were synthesized using the protein sol–gel method, resulting in an average crystallite size of 8, 27, and 67 nm for 623, 773, and 1073 K, respectively. Sample characterizations were conducted through X-ray fluorescence, X-ray diffraction, VSM magnetic measurements, and Mössbauer spectroscopy for further analysis of the performance. The sensor exhibited a linear response, achieving a maximum regression between 93.0% and 98.6% across all sample points in the 0 to 150 Oe range, with an output power of approximately 20 dBm, correlated with the applied magnetic field. Sensitivity was measured at 1.15, 0.93, and 1.41 dB/Oe. Previous studies have correlated the horizontal width of the hysteresis loop with sensor saturation. However, by employing a different coating in this work, we complement these findings by demonstrating that the sensor does not saturate if the maximum applied field is smaller than the hysteresis loop width. [ABSTRACT FROM AUTHOR]

Humidity sensors deeply influence human manufacturing production and daily life, while researchers generally focus on developing humidity sensors with higher stability, higher linearity, rapid response time, etc. Yet, few people discuss measuring humidity in the microenvironment by miniaturizing sensor size into a microscale, in which the existing humidity sensors are difficult to reach. Accordingly, this study proposes a methodology for measuring relative humidity in the microscale by utilizing the distinctive morphologies of Equisetum spores across a range of relative humidities between 50% and 90%. Equisetum spores are responsive to changes in ambient relative humidity and remain in their original activities even after iron sputtering, which aims to endow the sensor with magnetic properties. The test performed in this study demonstrated a response time of 3.3 s and a recovery time of 3.6 s. In the first application, we employed such microscale sensors to work in the channel of the microfluidic chip or the cell migration microchip, as an example of working in the microenvironment. COMSOL Multiphysics 6.2 software was also used to simulate the change in relative humidity in such microchannels. Secondly, such microscale sensors are combined with smartphone-based microscopy to measure the humidity of the skin. These microscale sensors pave the new way to sensing humidity in microenvironments. [ABSTRACT FROM AUTHOR]

Due to their compact structure and low laying cost, three-core power cables are widely used for power distribution networks. The three-phases of such cables are distributed symmetrically with a 120° shift to each other. Phase current is an important parameter to reflect the operation state of the power system and three-core cable. Three-core symmetrical power cables use a common shield, leading to magnetic field cancelation outside the cable during steady operation. Thus, traditional magnetic-based current transformers cannot measure the phase current on three-core cable non-invasively. In order to measure the phase current more conveniently, a phase current measurement method for three-core cables based on a magnetic sensor is proposed in this paper. Nonlinear equations of a phase current and the magnetic field of a measuring point are constructed. The calculated magnetic field distribution of the three-core cable is verified using a finite element simulation. The effectiveness of the measurement method is further validated through experiments. This proposed method is able to conveniently detect the phase current of three-core power cables, which can help cable maintenance. [ABSTRACT FROM AUTHOR]

Electromagnetic tracking (EMT) can benefit image-guided interventions in cases where line of sight is unavailable. However, EMT can suffer from electromagnetic distortion in the presence of metal instruments. Metal instruments are widely used in laparoscopic surgery, ENT surgery, arthroscopy and many other clinical applications. In this work, we investigate the feasibility of tracking such metal instruments by placing the inductive sensor within the instrument shaft. We propose a magnetostatic model of the field within the instrument, and verify the results experimentally for frequencies from 6 kHz to 60 kHz. The impact of the instrument's dimensions, conductivity and transmitting field frequency is quantified for ranges representative of typical metal instruments used in image-guided interventions. We then performed tracking using the open-source Anser EMT system and quantify the error caused by the presence of the rod as a function of the frequency of the eight emitting coils for the system. The work clearly demonstrates why smaller tool diameters (less than 8 mm) are less susceptible to distortion, as well as identifying optimal frequencies (1 kHz to 2 kHz) for transmitter design to minimise for distortion in larger instruments. [ABSTRACT FROM AUTHOR]

By using density functional theory (DFT), the adsorption behavior of gas molecules on defective graphene doped with manganese and nitrogen were investigated. The geometric structure, electronic structure, and magnetic properties of two substrates were calculated and the sensing mechanism was also analyzed. The results indicate that the MnSV-GP and MnN3-GP have stronger structural stability, in which Mn atoms and their coordination atoms will become the adsorption point for five gas molecules (CH2O, CO, N2O, SO2, and NH3), respectively. Moreover, at room temperature (298 K), the recovery time of the MnSV-GP sensor for N2O gas molecules is approximately 1.1 s. Therefore, it can be concluded that the MnSV-GP matrix as a magnetic gas sensor has a promising potential for detecting N2O. These results also provide a new pathway for the potential application of Mn-doped graphene in the field of gas sensors. [ABSTRACT FROM AUTHOR]

This paper introduces a novel class of low-loss and cost-effective optical planar structures tailored for magnetic detection applications. These structures represent unconventional magneto-plasmonic devices specifically optimized for an 'optical switch' configuration. The structure consists of a 1D deep sinusoidal gold grating covered by a thin cobalt layer. In this unique arrangement, the excited plasmon induces a high-contrast switching phenomenon between the reflected free space intensity of specular (0th) and −1st diffracted orders, sensitive to any transverse magnetic fields applied to the cobalt layer. The use of these two distinct diffracted orders induces differential measurements, effectively mitigating common drift and perturbations. This innovative approach results in an enhanced detection sensitivity, showcasing the potential of these structures for advanced magnetic field sensing applications. [ABSTRACT FROM AUTHOR]

Magneto-oscillatory devices have been recently developed as very potent wireless miniature position trackers and sensors with an exceptional accuracy and sensing distance for surgical and robotic applications. However, it is still unclear to which extend a mechanically resonating sub-millimeter magnet interacts with external magnetic fields or gradients, which induce frequency shifts of sub-mHz to several Hz and, therefore, affect the sensing accuracy. Here, we investigate this effect experimentally on a cantilever-based magneto-oscillatory wireless sensor (MOWS) and build an analytical model concerning magnetic and mechanical interactions. The millimeter-scale MOWS is capable to detect magnetic fields with sub-µT resolution to at least ±5 mT and simultaneously detects magnetic field gradients with a resolution of 65 µT/m to at least ±50 mT/m. The magnetic field sensitivity allows direct calculation of mechanical device properties, and by rotation, individual contributions of the magnetic field and gradient can be analyzed. The derived model is general and can be applied to other magneto-oscillatory systems interacting with magnetic environments. [ABSTRACT FROM AUTHOR]

In recent years, there has been a significant increase in the prevalence of electronic wearables, among which flexible magnetoelectronic skin has emerged as a key component. This technology is part of the rapidly progressing field of flexible wearable electronics, which has facilitated a new human perceptual development known as the magnetic sense. However, the magnetoelectronic skin is limited due to its low sensitivity and substantial field limitations as a wearable electronic device for sensing minor magnetic fields. Additionally, achieving efficient and non-destructive delamination in flexible magnetic sensors remains a significant challenge, hindering their development. In this study, we demonstrate a novel magnetoelectronic touchless interactive device that utilizes a flexible giant magnetoresistive sensor array. The flexible magnetic sensor array was developed through an electrochemical delamination process, and the resultant ultra-thin flexible electronic system possessed both ultra-thin and non-destructive characteristics. The flexible magnetic sensor is capable of achieving a bending angle of up to 90 degrees, maintaining its performance integrity even after multiple repetitive bending cycles. Our study also provides demonstrations of non-contact interaction and pressure sensing. This research is anticipated to significantly contribute to the advancement of high-performance flexible magnetic sensors and catalyze the development of more sophisticated magnetic electronic skins. [ABSTRACT FROM AUTHOR]

4H‐SiC is a key enabler for realizing integrated electronics operating in harsh environments, which exhibit very high temperatures. Through advances in 4H‐SiC process technology, different sensor and circuit types have been demonstrated to operate stable at temperatures as high as 800 °C, paving the way toward harsh‐environment immune smart sensors. In this work, for the first time the operation of ion‐implanted 4H‐SiC Hall sensors realized in a wafer scale Bipolar‐CMOS‐DMOS technology is demonstrated at a wide operation temperature range spanning room temperature up to 500 °C in addition to short‐term operation up to 600 °C. The temperature‐dependent sensor characteristics of 15–22 samples are evaluated in terms of sensitivity and noise. The small inter‐device variations reflect the stability of the used process for very high temperature Hall sensors. The noise‐limited detectivity is further evaluated, revealing a best value of 950 nT/Hz$\sqrt{\mathrm{Hz}}$ and a mean detectivity of 1 µT/Hz$\sqrt{\mathrm{Hz}}$ at 500 °C. This is the best value reported up to date for very high temperature Hall sensors, besides being the first demonstration of ion‐implanted wide‐bandgap Hall sensors. Overall, the results reflect the potential of the demonstrated Hall sensors for the next generation of integrated magnetic field sensors in harsh environments. [ABSTRACT FROM AUTHOR]

Generally, the measurement of power line current is done by measuring the magnetic field around it, so how to increase the magnetic field at the sensor head is the key to achieve high sensitivity detection. A ferrite magnetic circuit (FMC) system was proposed to improve the conversion efficiency of transmission line current to magnetic field at the sensor head. The FMC is designed as a rectangular structure with a slit in which the sensing head is placed. The magnetic field generated by the current is concentrated at the sensing head by using the high permeability of ferrite. The simulation results shows that the magnetic field in the slit is mainly determined by magnetic permeability, the length and the cross-sectional area of the magnetic bar. It monotonically increases with the increasing of magnetic permeability, and decreased gradually with the slit width increasing. It increased rapidly at first and then increased slowly with the increasing of the cross-sectional area of the magnetic bar. It has a good practical value to improve the sensitivity of optical fiber current sensor. [ABSTRACT FROM AUTHOR]

In this paper, a novel microelectromechanical system (MEMS) inertial switch with self-latching mechanism and adjustable acceleration threshold is proposed. The switch consisted of a proof mass suspended by flexible springs. Permanent magnets, ferromagnets and planer coils were integrated in the device to realize the latching and threshold tuning mechanism. The centrifugal experiment and laser based position measurement have been conducted to measure the acceleration threshold and the stiffness of the spring respectively. The inertial threshold value and the spring stiffness were measured as 5.27 g and 163.12 N/m. The discrepancy between measured acceleration threshold results (5.27 g) and the analytical acceleration threshold results (5 g) is mainly due to the dimension errors during device fabrication. By applying a reverse current of 0.1 A, the switch can be unlatched from its 'on-state'. Experiment also demonstrates that by applying a current varying from − 0.5 A to 0.5 A, the threshold value can be adjusted from 6 g to 3.75 g. [ABSTRACT FROM AUTHOR]

The integration of nanocomposite thin films with combined multifunctionalities on flexible substrates is desired for flexible device design and applications. For example, combined plasmonic and magnetic properties could lead to unique optical switchable magnetic devices and sensors. In this work, a multiphase TiN-Au-Ni nanocomposite system with core–shell-like Au-Ni nanopillars embedded in a TiN matrix has been demonstrated on flexible mica substrates. The three-phase nanocomposite film has been compared with its single metal nanocomposite counterparts, i.e., TiN-Au and TiN-Ni. Magnetic measurement results suggest that both TiN-Au-Ni/mica and TiN-Ni/mica present room-temperature ferromagnetic property. Tunable plasmonic property has been achieved by varying the metallic component of the nanocomposite films. The cyclic bending test was performed to verify the property reliability of the flexible nanocomposite thin films upon bending. This work opens a new path for integrating complex nitride-based nanocomposite designs on mica towards multifunctional flexible nanodevice applications. [ABSTRACT FROM AUTHOR]

A renewable electrochemical screen-printed electrode (SPE) is proposed based on magnetic bamboo-like nitrogen-carbon (N–C) nanotubes loaded with nickel–cobalt alloy (NiCo) nanoparticles (NiCo@N-CNTs) for the determination of ractopamine (RAC). During the preparation of NiCo@N-CNTs, Co-MOF-67 (ZIF-67) was firstly synthesized, and then blended with dicyandiamide and nickel acetate, followed by a one-step pyrolysis procedure to prepare NiCo@N-doped carbon nanotubes. The surface morphology, structure, and chemical composition of NiCo@N-CNTs were characterized by SEM, TEM, XRD, XPS, and EDS. The electrocatalytic and electrochemical behavior of NiCo@N-CNTs were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results demonstrated that NiCo@N-CNTs possessed remarkable conductivity and electrocatalysis to the oxidation of ractopamine (RAC). By using screen-printed electrode (SPE), NiCo@N-CNTs, and a designed base support, a magnetic RAC sensor (NiCo@N-CNTs/SPE) was successfully constructed. It presented a detection linear range of 0.05–80 μM with a detection limit of 12 nM (S/N = 3). It also exhibited good sensitivity, reproducibility, and practicability in spiked real pork samples. Since the adhesion of NiCo/N-CNTs on SPE was controlled by magnet, the NiCo@N-CNTs was easily detached from the SPE surface by magnetism and thus displayed excellent renewability. This work broadened insights into portable devices for on-site and real-time analysis. [ABSTRACT FROM AUTHOR]

This paper is devoted to the characterization of magnetohydrodynamics (MHD) tearing modes causing plasma–wall interaction (PWI) in the Reversed-Field eXperiment (RFX-mod) reversed-field pinch (RFP) device. We study an example of a magnetic reconnection event in a high plasma current discharge. The PWI is measured via a fast camera looking at the graphite-covered inner wall, showing two separated footprints of neutral carbon radiation. A first, simple analysis shows that the phase-locking of m = 1 tearing modes is the principal cause of enhanced PWI, as it is well documented in literature. Many modes contribute to the phase-locking, actually more than those measured with the magnetic sensors. A more refined analysis is based on calculation of the Connection Length to the wall and of the loss time of Maxwellian ions via the Hamiltonian guiding center code Orbit. This analysis confirms the importance of the m = 1 phase-locking as a loss channel of high-energy particles, which is the mechanism that dominates the PWI pattern, but an additional role of the m = 0 , n = 7 mode is highlighted, which is a new result for the RFP. The PWI mediated by the m = 0 islands is milder, which is a good outlook for the RFX-mod2 upgraded device, currently in the assembly phase. [ABSTRACT FROM AUTHOR]

High-sensitivity magnetic sensors are fundamental components in fields such as biomedicine and non-destructive testing. Flux concentration technology enhances the sensitivity of magnetic sensors by amplifying the magnetic field to be measured, making it the most effective method to improve the magnetic field resolution of magnetic sensors. Superconductors and high-permeability soft magnetic materials exhibit completely different magnetic effects. The former possesses complete diamagnetism, while the latter has extremely high magnetic permeability. Both types of materials can be used to fabricate flux concentrators. This paper compares superconducting and soft magnetic flux concentration technologies through theoretical simulations and experiments, investigating the impact of different structural parameters on the magnetic field amplification performance of superconducting and soft magnetic concentrators. This research is significant for the development of magnetic focusing technology and its applications in weak magnetic detection and other fields. [ABSTRACT FROM AUTHOR]

The study aimed to investigate the underlying physics limiting the temperature stability and performance of non-surface passivated Al0.34Ga0.66N/GaN Hall effect sensors, including contacts, under atmospheric conditions. The results obtained from analyzing the microstructural evolution in the Al0.34Ga0.66N/GaN Hall sensor heterostructure were found to correlate with the electrical performance of the Hall effect sensor. High-resolution x-ray photoelectron spectroscopy studies revealed the signature of surface oxidation in the GaN cap layer, as well as a slight out-diffusion of "Al" from the AlGaN barrier layer. To prevent the formation of a bumpy surface morphology at the Ohmic contact, we investigated the impact of "Pt" top Ohmic contacts. The application of a top "Pt" contact stack resulted in a smooth Ohmic contact surface and provided evidence that the bumpy surface morphology in Au-based Ohmic contacts is due to the formation of an Al-Au viscous alloy during rapid thermal annealing. In the early stages of thermal aging, the small drop in contact resistivity stabilized with subsequent thermal aging past the initial 550 h at 200 °C. The outcome is that the Al0.34Ga0.66N/GaN Hall effect sensors, even without surface passivation, exhibited a stable response to applied magnetic fields with no sign of significant degradation after 2800 h of thermal aging at 200 °C under atmospheric conditions. This observed stability in the Hall sensor without surface passivation can be attributed to a self-imposed surface oxidation of the cap layer during the early stages of aging, which serves as a protective layer for the device during subsequent extended periods of thermal aging at 200 °C. [ABSTRACT FROM AUTHOR]

Two‐photon excited fluorescence materials with sufficient responsiveness to magnetic field are essential for applications such as 3D mapping of magnetic field distributions based on magneto‐optical effect. In this study, a two‐photon excited magneto‐photoluminescence (MPL) in the intermolecular exciplex of 1,1‐bis[(di‐4‐tolylamino)phenyl]cyclohexane and tris(2,4,6‐trimethyl‐3‐(pyridin‐3‐yl)phenyl)borane (TAPC:3TPYMB) is observed. This MPL can be attributed to the promotion of delocalization of excitons in the exciplex under two‐photon excitation, resulting in a weakened spin‐exchange interaction and thereby enhancing the magnetic field‐sensitive spin conversion process. The temperature‐dependent MPL further validates the strong correlation between the delocalization of excitons in the exciplex and the enhanced MPL observed during temperature variation. Combining the penetration capability and magneto‐optical effect of two‐photon excited fluorescence in TAPC:3TPYMB exciplex, a novel magnetic sensor suitable for 3D mapping of magnetic field distributions is further developed. The present work not only enhances the understanding of the magneto‐optical coupling mechanism but also opens up opportunities for the application of molecular materials in opto‐spintronic devices. [ABSTRACT FROM AUTHOR]

For social animals, including humans, it is important to build strong social bonds, reduce tension, and prevent conflicts to maintain the society. One way to strengthen these social bonds is through behavioral synchrony, where individuals perform the same actions together. Behavioral synchrony has been observed across various animal species and is thought to lead to emotional synchrony. Dogs, which have lived with humans for tens of thousands of years, are known to form a special bond with their human owners. Given this strong bond between dogs and humans, it is possible that they exhibit behavioral synchrony. Previous research has shown yawning synchronization between dogs and humans, but it is unknown whether breathing synchrony, which is a type of behavioral synchrony, exists. This study aimed to investigate whether dogs and humans exhibit breathing synchrony. We used a high-sensitivity magnetic sensor to measure respiration in dogs and a thermocouple to measure human respiration. Our results found that dogs' breathing patterns were influenced by humans' breathing, suggesting the presence of breathing synchrony between them. This study extends the understanding of human-canine communications by using non-invasive technology. [ABSTRACT FROM AUTHOR]

Extremely large magnetoresistance (XMR) is highly applicable in spintronic devices such as magnetic sensors, magnetic memory, and hard drives. Typically, XMR is found in Weyl semimetals characterized by perfect electron–hole symmetry or exceptionally high electric conductivity and mobility. Our study explores this phenomenon in a recently developed graphene moiré system, which demonstrates XMR owing to its topological structure and high-quality crystal formation. We investigate the electronic properties of three-dimensional intertwined twisted graphene spirals (TGS), manipulating the screw dislocation axis to achieve a rotation angle of 7.3°. Notably, at 14 T and 2 K, the magnetoresistance of these structures reaches 1.7 × 107%, accompanied by a metal–insulator transition as the temperature increases. This transition becomes noticeable when the magnetic field exceeds a minimal threshold of approximately 0.1 T. These observations suggest the possible existence of complex, correlated states within the partially filled three-dimensional Landau levels of the 3D TGS system. Our findings open up possibilities for achieving XMR by engineering the topological structure of 2D layered moiré systems. Twisted graphene spirals are emerging material structures that may host topological phenomena. Here, the authors demonstrate extremely large magnetoresistance and a metal-insulator transition in twisted graphene spirals. [ABSTRACT FROM AUTHOR]