Magnetic Field Sensor Research Articles

Dual-Channel High-Sensitivity Temperature and Magnetic Field Sensor Based on Mach–Zehnder Interference and Surface Plasmon Resonance

Dual-Channel High-Sensitivity Temperature and Magnetic Field Sensor Based on Mach–Zehnder Interference and Surface Plasmon Resonance

Numerical study of a tapered fiber magnetic field sensor based on the ENZ mode

This study introduces what we believe to be a novel magnetic field sensor that utilizes a tapered optical fiber coated with indium tin oxide (ITO) and titanium dioxide (TiO2), operating on an epsilon-near-zero (ENZ) mode. The evanescent field around the tapered optical fiber can excite the ENZ mode of the ITO film, and the TiO2 layer can ensure the phase matching between the fiber core mode and the ENZ mode. The sensor, immersed in magnetic fluid, leverages the unique properties of ENZ materials to achieve a high sensitivity and resolution in the near-infrared (NIR) region. Through a simulation, the sensor demonstrated a maximum sensitivity of 6900 nm/RIU and a magnetic field sensitivity of 370 pm/Oe. The findings suggest that ENZ mode-based optic sensing presents a promising alternative to traditional plasmonic sensing methods, offering potential applications in various fields requiring precise magnetic field measurements.

Magnetic field sensor based on multiple Fano resonance in metal-insulator-metal waveguide coupled with cross-shape resonator

Abstract In this paper, an innovative plasmonic magnetic field sensor (MFS) that exploits a Metal-insulator-Metal (MIM) waveguide configuration with an asymmetric cross-shaped resonator is constructed. The design enables the observation of double Fano resonance in the transmission spectrum, resulting from the coupling between continuous spectrum and discrete spectrum. By incorporating magnetic fluid in the asymmetric cross-shape resonator, the Fano line shapes can be tuned by the external magnetic field. Finite-Difference Time-Domain (FDTD) is used to simulate the spectra response to external magnetic fields and geometrical sizes. The proposed structure exhibits remarkable magnetic field sensitivity of 12.1 p m / O e within the detection range of 15 O e to 199 O e . The resolution of MIM magnetic field sensors can reach 0.0826 O e . The optimal figure of merit (FOM) and maximum Q factor of the Fano dip are about 6.9 × 10 − 4 / O e and 66.74, respectively. Meanwhile, The proposed Fano resonance MFS has some advantages, including compact size, high sensitivity, and cost-effectiveness. A strong linear relationship between the magnetic field and resonance wavelength indicates that the proposed structure can find potential applications in diverse fields such as magnetic field sensors, aircraft navigation, and even nuclear energy generation.

Eccentric Core Photonic Crystal Fiber Magnetic Field Sensor Based on Surface Plasmon Resonance with Extremely High Linearity

Eccentric Core Photonic Crystal Fiber Magnetic Field Sensor Based on Surface Plasmon Resonance with Extremely High Linearity

Longitudinal (α33) and transverse(α31) dynamic magnetoelectric hysteretic response for CoFe1.88Dy0.12O4–K0.5Na0.5NbO3 lead-free multiferroic laminates

The magnetoelectric (ME) laminate structures of CoFe1.88Dy0.12O4 (CFDO, Ferrite) and K0.50Na0.50NbO3 (KNN, ferroelectric/piezoelectric) phases were fabricated by silver epoxy bonding technique and tested the ME response in longitudinal and transverse mode. The CFDO reveals the cubic spinel structure while KNN reveals the perovskite orthorhombic crystal structures having dense microstructure. The CFDO confirms the phase segregation of the DyFeO3ortho-ferrite phase, while the KNN lead-free ceramic showed the Curie temperature of 416 °C, 13µC/cm2 maximum polarization, 25,296 × 10-15 m2/N figure of merit, piezoelectric charge coefficient d33 of 47 pC/N. The longitudinal (α33) and transverse (α31) dynamic magnetoelectric response is studied to figure out the effective magnetic field direction to get better values of magnetoelectric voltage sensitivity i.e. αME. Both modes revealed the hysteretic behavior i.e. lagging of ME voltage response to an applied magnetic field which evidences a true multiferroic character of CFDO/KNN laminates. Remarkably, the (CFDO /KNN/ CFDO) structure demonstrated a substantial magnetoelectric coefficient in LT (α31) mode of approximately 38.5 mV/cm·Oe at a magnetic field of 400 Oe and −37.55 mV/cm·Oe at a magnetic field of −400 Oe. Thus, here we present the magnetoelectric laminate structure of CFDO /KNN/ CFDO phases beneficial for magnetic field sensors.

Modeling and Measurement of CMOS-Based Three-Axis Magnetic Field Sensors With Low Cross-Sensitivity

Modeling and Measurement of CMOS-Based Three-Axis Magnetic Field Sensors With Low Cross-Sensitivity

Design and implementation of a nondestructive testing system for magnetic field imaging based on machine learning

This study presents the design of a nondestructive testing (NDT) system for detecting metal defects using a magnetic field sensor array. The system integrates a hardware-software detection framework that includes parallel computation and processing cores, along with multiple anisotropic magnetoresistance (AMR) sensors. These AMR sensors capture subtle variations in the magnetic field, which serve as the foundation for defect identification. The system enables synchronized data acquisition from multiple AMR sensors, achieving multi-axis data fusion and parallel signal processing. Furthermore, the detection system gathers defect features to train an NDT system based on machine learning (ML). Subsequently, ML-generated defect imaging features are processed through an imaging framework, producing magnetic field imaging (MFI) for precise defect localization. The study tested six different metal samples with various defect sizes and types to validate the system. The results demonstrate the system’s ability to accurately detect and identify different defects, highlighting the high precision of magnetic field detection and the overall effectiveness of the proposed system for NDT.

Magnetic Field-Induced Polar Order in Monolayer Molybdenum Disulfide Transistors.

In semiconducting monolayer transition metal dichalcogenides (ML-TMDs), broken inversion symmetry and strong spin-orbit coupling result in spin-valley lock-in effects so that the valley degeneracy may be lifted by external magnetic fields, potentially leading to real-space structural transformation. Here, magnetic field (B)-induced giant electric hysteretic responses to back-gate voltages are reported in ML-MoS2 field-effect transistors (FETs) on SiO2/Si at temperatures <20 K. The observed hysteresis increases with |B| up to 12 T and is tunable by varying the temperature. Raman spectroscopic and scanning tunneling microscopic studies reveal significant lattice expansion with increasing |B| at 4.2 K, and this lattice expansion becomes asymmetric in ML-MoS2 FETs on rigid SiO2/Si substrates, leading to out-of-plane mirror symmetry breaking and the emergence of a tunable out-of-plane ferroelectric-like polar order. This broken symmetry-induced polarization in ML-MoS2 shows typical ferroelectric butterfly hysteresis in piezo-response force microscopy, adding ML-MoS2 to the single-layer material family that exhibits out-of-plane polar order-induced ferroelectricity, which is promising for such technological applications as cryo-temperature ultracompact non-volatile memories, memtransistors, and ultrasensitive magnetic field sensors. Moreover, the polar effect induced by asymmetric lattice expansion may be further generalized to other ML-TMDs and achieved by nanoscale strain engineering of the substrate without magnetic fields.

DESIGN AND FABRICATION OF SHAPE MORPHING MAGNETO-IMPEDANCE MAGNETIC SENSOR

The magnetoimpedance (MI) effect is characterized by the alteration in the impedance of soft magnetic materials when subjected to a magnetic field while a high-frequency alternating current flows through them. In this study, we engineered two distinct sensor architectures utilizing amorphous FeCSi magnetic ribbon: a single-bar structure with the dimension of 10 mm × 90 μm × 20 μm and a meander structure consisting of 13 parallel single bars. These structures were miniaturized through advanced techniques combining laser engraving and chemical etching. The magnetic analysis reveals that the meander structure exhibits a pronounced dependency on the angle θ between the magnetic field and the sensor orientation, enhancing its soft magnetic properties by up to fivefold compared to the single-bar design. This enhancement might be attributed to a reduction in the demagnetization effect and shape anisotropy energy within the meander sensor. Furthermore, the analysis of the MI effect indicates that the resonance frequency remains unaffected by external magnetic fields for both sensor types. Notably, the meander sensor demonstrates exceptional MI ratio values exceeding 82%, representing a remarkable 24-fold increase over the 3.5% observed in the single-bar sensor. Additionally, the isotropy - quantified as the MI ratio's dependence on angle θ, and magnetic field sensitivity are significantly improved in the meander configuration. These advancements in soft magnetic and physical properties are correlated to the domain structure of the sensor, particularly its transverse magnetic permeability, as evidenced by micromagnetic simulations conducted using Mumax3. With its superior MI ratio, isotropy, and heightened magnetic field sensitivity, the meander-type magnetic field sensor presents substantial potential for applications across diverse fields, ranging from biological systems to specialized practical missions.

Adhesion layers between piezoelectric and magnetostrictive layers in a MEMS magneto-sensor stack: Influence on the phase transformation of deposited Co/Fe multilayers to magnetostrictive CoxFe1−x phase

Magnetoelectric MEMS devices, such as magnetic field sensors, may be composed of a multilayer stack as a magnetostrictive layer, which is mechanically coupled to a piezoelectric film. Good adhesion and a stable rigid interface have to be maintained for such a sensor. Certain electric and magnetic properties, especially the magnetostriction, have to reach sufficiently high values, which can be achieved by selected phases or mixtures of phases. In this study, Co/Fe multilayers with varied bilayer periods are deposited onto AlN or Sc0.14Al0.86N coated Si substrates by DC magnetron sputtering with the optional insertion of a 5 nm thick adhesion layer of Cr or Zr to investigate its influence on the formation of the desired mixture of bcc and fcc Co0.7Fe0.3 phases, which are expected to yield a high magnetostrictive strain, after an RTA at 800 °C. A qualitative phase analysis is made by XRD in Bragg-Brentano geometry and shows that the bcc + fcc mixture can be achieved with a Cr interlayer. A sharp, void free, and undamaged interface for that case was observed in SEM images of cross sections prepared with FIB.

On the Origin of Signal and Bandwidth of Converse Magnetoelectric Magnetic Field Sensors

AbstractConverse magnetoelectric sensors enable the detection of low‐frequency and low‐amplitude magnetic fields over a bandwidth of several kilohertz by combining the electrical excitation of a magnetoelectric resonator via a piezoelectric layer with an inductive readout. Here, a comprehensive sensor model is presented to further foster the development of this promising sensor concept. The model relates the output signal to the device characteristics, taking into account the magnetoelastic and electromechanical properties, the resonator geometry, and operating conditions. The sensor system is thoroughly experimentally analyzed to validate the model. Based on the analysis, the sensor concept is explained in detail, including the origin of its loss and bandwidth and their connection with the magneto‐mechanical loss in the magnetostrictive layer. Significant advances have been made in the comprehensive understanding of converse magnetoelectric sensors, providing a solid basis for future improvements in magnetoelectric sensor systems.

Ultrahigh Sensitivity Surface Plasmon Resonance Magnetic Field Sensor Based on Side-Core Inscribed Capillary Fiber

Ultrahigh Sensitivity Surface Plasmon Resonance Magnetic Field Sensor Based on Side-Core Inscribed Capillary Fiber

CMOS-compatible plasmonic magnetic field sensor: An alternative approach using ultra-compact MIM configuration

This paper introduces a novel magnetic field sensor (MFS) that utilizes a metal-insulator-metal (MIM) waveguide integrated with a resonator structure and incorporates water-based Fe3O4 magnetic fluid. The sensor uses titanium nitride (TiN) as the plasmonic material which offers numerous advantages over conventional noble plasmonic materials. The sensor takes advantage of the tunable optical properties of the magnetic fluid and TiN to detect changes in the external magnetic field and quantify the magnetic field strength which has been demonstrated using the Finite Element Method (FEM). Our proposed MFS exhibits a high sensitivity of 11.97 pm/Oe, a narrow-band full-width half maximum of 93.66 nm, and a resolution of 8.36 × 10−4 Oe. The sensor is also compatible with complementary metal oxide semiconductor (CMOS) fabrication techniques, which enables chip-scale integration and low-cost production. The sensor can be used for various applications in navigation, military, space, healthcare, and beyond.

Fiber-Optic Magnetic Field Sensor Based on Four-Tapered-In-Tapered Structure

Fiber-Optic Magnetic Field Sensor Based on Four-Tapered-In-Tapered Structure

A Polyimide Composite-Based Electromagnetic Cantilever Structure for Smart Grid Current Sensing.

Polyimides (PIs) have been extensively used in thin film and micro-electromechanical system (MEMS) processes based on their excellent thermal and mechanical stability and high glass transition temperature. This research explores the development of a novel multilayer and multifunctional polymer composite electro-piezomagnetic device that can function as an energy harvester or sensor for current-carrying wires or magnetic field sensing. The devices consist of four layers of composite materials with a polyimide matrix. The composites have various nanoparticles to alter the functionality of each layer. Nanoparticles of Ag were used to increase the electrical conductivity of polyimide and act as electrodes; lead zirconate titanate was used to make the piezoelectric composite layer; and either neodymium iron boron (NdFeB) or Terfenol-D was used to make the magnetic and magnetostrictive composite layer, which was used as the proof mass. A novel all-polymer multifunctional polyimide composite cantilever was developed to operate at low frequencies. This paper compares the performance of the different magnetic masses, shapes, and concentrations, as well as the development of an all-magnetostrictive device to detect voltage or current changes when coupled to the magnetic field from a current-carrying wire. The PI/PZT cantilever with the PI/NdFeB proof mass demonstrated higher voltage output compared to the PI/Terfenol-D proof mass device. However, the magnetostrictive composite film could be operated without a piezoelectric film based on the Villari effect, which consisted of a single PI-Terfenol-D film. The paper illustrates the potential to develop an all-polymer composite MEMS device capable of acting as a magnetic field or current sensor.

Fiber optic magnetic field sensor based on a magnetic-fluid-induced phase-shift FLRD

A magnetic field sensing system based on a phase-shift fiber loop ring-down (FLRD) technique and multi-mode interferometer (MI) coated with magnetic fluid (MF) is proposed and demonstrated. The MI is constructed by splicing a segment of no-core fiber between two sections of single-mode fibers, which is then immersed in MF to serve as a sensing head with the advantages of simple fabrication and specific magnetic sensitivity. Due to the magnetic refractive index tunable properties of the MF, the magnetic-field-dependent loss will be introduced in the fiber loop by the sensing head. Such magnetic-induced loss would be accumulated during the round trip of the optical carrier and reflected on the phase information of the modulated signal. The phase-shift changes with the applied magnetic field strength, enabling magnetic field sensing through phase-shift measurements. The sensing system is experimentally demonstrated and a sensitivity of 0.704×10−3deg/Gs in the linear region is achieved. Moreover, the stability and repeatability of the system are verified, leading to a promising method for magnetic field measurements.

Relative position estimation using modulated magnetic field for close proximity formation flight

This paper presents a method to estimate relative position vectors between spacecraft equipped with magnetic coils and magnetic field sensors for close proximity operation. Filters can segregate a magnetic field with a particular frequency if spacecraft drive their coils with this specific frequency. The proposed method utilizes the amplitude of the magnetic field with a particular frequency to estimate relative position vectors. The method consists of an initial position estimator and a sequential position estimator, which is an unscented Kalman filter. The initial position estimator provides a coarse estimate for the relative position vectors using the segregated magnetic field. Relation between the magnetic field and relative position vector is derived analytically in this article for the initial position estimator. The unscented Kalman filter refines the estimation accuracy by initializing the filter with the estimate by the initial position estimator. It is shown that a spacecraft can conduct relative position vector estimation using the magnetic field of a target spacecraft, provided that a few conditions clarified in the article are satisfied. Finally, the proposed estimators are evaluated numerically via simulations.

Reducing equivalent magnetic noise by electrode design and magnetic annealing in Quartz/Metglas magnetoelectric sensors

Magnetoelectric (ME) composites are promising for the development of high-performance magnetometers due to their high sensitivity, low cost, low power consumption, and small size. Enhancing the ME coefficient while reducing the background noise is an effective method to improve the performance of ME sensors, which remains challenging. In this work, we propose a method to reduce the equivalent magnetic noise by optimizing the electrode design and the magnetic annealing process in magnetoelectric quartz/Metglas composites. Compared with the non-optimized ME composites, the ME coefficient increases by 1.38 times while the background noise decreases by about 0.78 times, resulting in a LoD of 10 fT at resonance. Due to the high ME coefficient and low background noise, the equivalent magnetic noise from 20 kHz to 50 kHz was less than 6.10 pT/Hz1/2. The results show that proper annealing treatment of Metglas is beneficial for improving the soft magnetic properties. Meanwhile, the hollow electrode of quartz can reduce the equivalent capacitance and enhance the quality factor of the piezoelectric layer. This work demonstrates a feasible way to enhance the performance of ME magnetic field sensors.

Unusual inverse spin Hall effect in Pt/Co/Pt multilayers on single-crystalline YIG

The inverse spin Hall effect (ISHE) is a significant phenomenon that enables the conversion of spin current into charge current, offering promising applications in novel spintronic devices. In conventional ISHE measurements, it is widely recognized that the spin polarization, spin current, and generated charge current are mutually perpendicular. This study systematically investigates the ISHE in Pt/Co/Pt multilayers grown on a single-crystalline yttrium iron garnet (YIG) layer. A non-zero ISHE voltage was obtained along the direction parallel to the external magnetic field within the YIG coercive field range, deviating from the classical ISHE behavior. Our investigation revealed that the in-plane magnetic anisotropy of single-crystalline YIG plays a crucial role, as the easy axis of YIG and the external magnetic field collaboratively determine the polarization direction of the spin current, especially when the external magnetic field is smaller than the YIG coercive force. Furthermore, by tuning the small in-plane magnetization component of the Pt/Co/Pt multilayers, which couples with the YIG magnetization, we were able to control the shape and reversal path of the ISHE voltage loop. These findings deepen our understanding of how magnetic order affects charge current flow in ISHE measurements. The variety of ISHE voltage loop shapes and reversal paths observed suggest potential applications for this device as a magnetic field sensor.

Recording of ultra-low frequency electromagnetic emission during loading of a rock sample

The review of publications devoted to the study and features of the registration of electromagnetic emission observed during the loading of samples of rocks, metals, composite materials in laboratory conditions, as well as in areas of disintegration of rock massifs at mining sites is given. Electromagnetic emission observed during the destruction of rock samples in laboratory experiments and field conditions can appear itself not only in the high and low frequency ranges (1000–3·106 Hz and 500–1000 Hz, respectively), but also in the very low and ultra-low frequency (200–500 Hz and 0.01–200.00 Hz, respectively) ranges. However, the overwhelming majority of experimental studies of rock samples under the influence of a destructive load in laboratory conditions are aimed at measuring electromagnetic emission of the high frequency range. An instrumentation and measurement complex is described that allows recording electromagnetic emission in the ultra-low frequency range. The composition of the instrumentation and measurement complex includes magnetic modulation transducers of magnetic induction as magnetic field sensors. The methodology of laboratory experiments on recording electromagnetic signals arising from the influence of an external load on rock samples using an instrumentation and measuring complex is presented. An example of uniaxial loading of a basalt sample is given. When loading the sample under consideration, the amplitude of the electromagnetic emission pulses exceeds the background values of technogenic magnetic noise by two orders of magnitude. The high sensitivity of the magnetic modulation transducer of magnetic induction allows it to be used to register the components of magnetic induction in the process of destruction of rock samples in conditions of interference from technogenic magnetic noise. The results obtained are important for monitoring and forecasting the process of cracking before mining impacts, as well as for studying the geological environment and processes that generate low-frequency electromagnetic emission in the mining areas.