Hall Element Research Articles

Study on the Side Effects of Hall Effect Based on Phase Change Method

The basic principle of some side effects in measuring electromagnetic induction intensity of Hall element is briefly introduced, and the effect of these side effects on the measurement results is discussed. It is preliminary that the effects of Nernst effect and Righi-Leduc effect on the experimental results are not significant and can be ignored, and the unequal potential difference contributes the most to the experimental results. In other experiments with Hall element as measuring instrument, it can also provide a reference for reducing system error.

A 3-D Force Sensor Based on Combination of Magnetic and Piezoresistive Transduction

Tactile sensors have been playing a crucial role in the operation of robot hands, especially in the analysis of grasping stability. However, the current three–dimensional (3-D) force sensors generally adopt the single sensing transduction(such as the capacitive 3-D force sensor only includes capacitance as a sensing transduction) and output the coupled signals, lacking accurate force decoupling. Here, we present a 3-D force sensor with self-decoupling by combining magnetic and piezoresistive transduction. Based on the characteristics of axially magnetized circular magnet, we explain the sensing principle of shear force which is using four Hall elements mounted with the cross-type to measure the shear force by detecting the sliding distance and direction of the magnet (can only move horizontally), and utilize a piezoresistive element to measure the normal force. In addition, we use a neural network to model the sensor response to improve the detection accuracy of shear force. The sensor resolutions for normal force and shear force are 0.3N and 0.2N, respectively, and the measurement ranges are more than 20N and 6N, respectively. By mounting our sensor at the gripper, we further show the performance of sensor for detecting 3-D force in the process of grasping object. The proposed 3-D force sensor could be beneficial for the adaptive grasping of robot hands.

Multi-Sensor Fault Diagnosis of Underwater Thruster Propeller Based on Deep Learning.

With the rapid development of unmanned surfaces and underwater vehicles, fault diagnoses for underwater thrusters are important to prevent sudden damage, which can cause huge losses. The propeller causes the most common type of thruster damage. Thus, it is important to monitor the propeller’s health reliably. This study proposes a fault diagnosis method for underwater thruster propellers. A deep convolutional neural network was proposed to monitor propeller conditions. A Hall element and hydrophone were used to obtain the current signal from the thruster and the sound signal in water, respectively. These raw data were fast Fourier transformed from the time domain to the frequency domain and used as the input to the neural network. The output of the neural network indicated the propeller’s health conditions. This study demonstrated the results of a single signal and the fusion of multiple signals in a neural network. The results showed that the multi-signal input had a higher accuracy than the one-signal input. With multi-signal inputs, training two types of signals with a separated neural network and then merging them at the end yielded the best results (99.88%), as compared to training two types of signals with a single neural network.

Calibration Method of Biotoxicity Monitoring Sensor in Seawater Environment

The behavior of marine organisms can indicate the quality of the seawater environment. By analyzing the abnormal behavior changes of bivalve aquatic organisms, the monitoring of marine biotoxicity can be carried out. The sensor based on Hall effect can monitor the behavior changes of bivalves and provide early warning of environment pollution. This paper proposed a calibration method for biotoxicity monitoring sensor based on bivalve aquatic organisms behavior. The calibration apparatus mainly included a Z-axis fine-tuning precision lifting platform, a plastic block, and a fixed bracket of sensor probe. By manually adjusting the knob on the z-axis fine-tuning precision lifting platform, the magnet on the sensor probe moved, and the output voltage of the Hall element changed. The rational fraction fitting was used for the calibration data and the coefficient of determination reached 0.9996. Experimental results showed that the proposed calibration method could achieve high precision calibration of the bivalve aquatic organisms behavior sensor.

Development of a novel Hall element inclinometer for slope displacement monitoring

Deep displacement monitoring of slopes is one of the most effective means for early warning, and it is of considerable significance for preventing landslide disasters. This paper introduces a novel inclinometer based on the Hall element sensor to monitor slope displacement. The Hall sensor units are connected in an array to form the inclinometer, which can realize deep-seated slope deformation monitoring. Furthermore, calibration, validation, and slope model experiments were carried out. The research shows that the Hall element can effectively sense magnetic flux density. Compared with other inclinometers, the novel inclinometer can achieve non-contact measurement with a large angle measuring range of −45° to 45° The measuring precision is 1% F.S. The performance of the inclinometer is stable and the maximum error of measurement is within −2.46 to 2.34 mm/m, which can meet the requirements of geotechnical engineering. So, the Hall element inclinometer is reliable for slope displacement monitoring.

The device and experimental study of the monitoring of the layered soil settlement

In order to solve the problems of large measurement error, low efficiency, complex equipment operation and difficult maintenance of layered soil settlement, this paper designed a new monitoring device of layered soil settlement based on Hall effect. A number of Hall elements are arranged on the monitoring circuit board at equal spacing, and the circuit board is fixed in the aluminum tube and sealed. The aluminum tube with multiple settlement magnetic rings is drilled into the earth vertically, and the settlement magnetic rings are distributed in different soil layers. The settlement of the soft soil will move the magnetic ring, causing its position to change, which will cause the change of magnetic flux density around Hall element, and the output voltage of Hall element will also change, and then the voltage signal will be transmitted to Hall signal concentrator through RS-485 bus communication mode. The Hall signal concentrator stores the signal in FLASH and communicates with the upper computer through using the LORA wireless communication module. Through data processing and model analysis in the upper computer, the function between Hall voltage and variation of displacement of the magnetic ring is fitted. Many experimental results indicated that the error of the monitoring device of layered settlement is within 1.0567mm, and the accuracy is high. It can provide real-time monitoring to different soil layers, and the data can be exported at any time, so it has a wider application prospect.

Output characteristics and experimental study of a highly linear and large-range force sensor based on the Villari effect

Based on the principle of the Villari effect, a force sensor with a giant magnetostrictive material (GMM) as the sensitive element, high linearity, and a large range was studied. A Hall element integrated into the structure was used to detect the magnetic flux density and measure the external force. First, the finite element method was used to verify the validity of the intended magnetization process. Second, an equation for GMM magnetization was derived based on the Jiles–Atherton (J–A) model and the magneto-mechanical coupling effect. The relationships between magnetization and the biased magnetic field, and magnetization and the external force were analyzed under the dynamic coupling model of positive and negative effects. Finally, the influences of various biased magnetic fields and external forces on the sensor output characteristics were determined experimentally. The sensitivity of the designed force sensor was 0.337 mV/N when the bias current was 1.2 A and the preload was 120 N. When a force of 1000 N was applied, the linearity was 0.82%. The experimental results are consistent with the theoretical design values. These research results aid in the development of a highly linear, large-range force sensor. This study provides the theoretical and technical foundations for a high-performance force sensor that can be used in industrial testing.

Charge-coupling effect in a Hall field element based on thin-film SOI-MOS transistor

The influence of the coupling effect on the parameters of field Hall elements based on thin-film MOS transistors has been studied. Analysis of the development of today’s microelectronics shows the necessity of developing the element base for high performance sensors based on silicon technologies. One way to significantly improve the performance of sensing elements including magnetic field sensors is the use of thin-film transistors on the basis of silicon on insulator (SOI) structures. It has been shown that field Hall sensors (FHS) may become the basis of high-performance magnetic field sensors employing the coupling effect occurring in the double gate vertical topology of these sensing elements. Electrophysical studies of FHS have been conducted for different gate bias and power supply modes. The results show that the coupling effect between the gates occurs in FHS if the thickness of the working layer between the gates is 200 nm. This effect leads to an increase in the effective carrier mobility and hence an increase in the magnetic sensitivity of the material. Thus field Hall elements based on thin-film transistors fabricated using silicon technologies provide for a substantial increase in the magnetic sensitivity of the elements and allow their application in highly reliable magnetic field sensors.

Composition optimization of InAsxSb1−x/AlyIn1−ySb quantum wells for Hall sensors with high sensitivity and high thermal stability

The band diagrams of InAsxSb1−x/AlyIn1−ySb quantum wells (QWs) were calculated covering a wide range of compositions of x and y. Various combinations of active (InAsxSb1−x) and barrier (AlyIn1−ySb) layers were investigated to optimize the Hall elements with high sensitivity and high thermal stability. For high sensitivity, x of 0.1–0.6 is desirable due to the band bowing effect to realize lower bandgaps compared with that of InSb in the active layer. Under the lattice matched conditions (y ∼ 1.22x), the QWs are type II QWs and the bottom of the conduction band is always lower than the Fermi level. Therefore, the QWs with x of 0.6 show large sheet carriers of 4.1 × 1011 cm−2 for 4.2 K without intentional doping, which contributes to the reduction in the temperature dependence of the transport properties. The barrier height monotonously increases with increasing y, and accordingly, the penetration depth of the wave function probability inside the barrier decreases. Under the lattice matched condition, the penetration depth drops significantly toward x = 0.4 (corresponding y ∼ 0.5) and then decreases slowly. Thus, x ≥ 0.4 (y ≥ 0.5) is preferable for a strong confinement effect, which could reduce interface scattering and, as a result, improve the electron mobility. Judging from these results, the optimized composition of the InAsxSb1−x/AlyIn1−ySb QW is x = 0.4–0.6 (under the lattice matched condition, corresponding y = 0.5–0.7).

Sensitivity Improvement of a Fully Symmetric Vertical Hall Device Fabricated in 0.18 μm Low-Voltage CMOS Technology

This paper proposes a new implementation method to significantly improve the magnetic sensitivity of a fully symmetric vertical Hall device (FSVHD) based on low-voltage CMOS technology. The FSVHD consists of four identical three-contact vertical Hall elements (3CVHE) and each 3CVHE is located in a low-doped deep n-well. The terminals of the 3CVHE are $\text{n}^{+}$ implanted in an n-well and a $\text{p}^{+}$ implantation in a p-well is performed to act as a trench between two adjacent $\text{n}^{+}$ contacts, enabling Hall current flowing deeply for sensitivity improvement. The influence of the geometry sizes on magnetic sensitivity is exploited utilizing TCAD simulation to obtain the optimized device structure in a $0.18~\mu\text{m}$ CMOS standard technology. The experimental results reveal that the proposed FSVHD with a $\text{p}^{+}$ /p-well trench can attain an improved voltage-related sensitivity of 8.4 mV/VT, which is about 70% higher than that of a conventional FSVHD without a trench in the same CMOS fabrication process, while offset and noise are not degraded. The proposed $\text{p}^{+}$ /p-well implantation trench is a good solution to enhance the sensitivity of a low-voltage CMOS VHD with a low manufacturing cost.

Coupling effect in field Hall elements based on thin-film SOI MOS transistors

The influence of the coupling effect on the parameters of field Hall elements based on thin-film MOS transistors has been studied. Analysis of the development of today’s microelectronics shows the necessity of developing the element base for high performance sensors based on silicon technologies. One way to significantly improve the performance of sensing elements including magnetic field sensors is the use of thin-film transistors on the basis of silicon on insulator (SOI) structures. It has been shown that field Hall sensors (FHS) may become the basis of high-performance magnetic field sensors employing the coupling effect occurring in the double gate vertical topology of these sensing elements. Electrophysical studies of FHS have been conducted for different gate bias and power supply modes. The results show that the coupling effect between the gates occurs in FHS if the thickness of the working layer between the gates is 200 nm. This effect leads to an increase in the effective carrier mobility and hence an increase in the magnetic sensitivity of the material. Thus field Hall elements based on thin-film transistors fabricated using silicon technologies provide for a substantial increase in the magnetic sensitivity of the elements and allow their application in highly reliable magnetic field sensors.

Study of SOI Field-Effect Hall Sensors in the Partial Depletion Mode

Earlier, when studying with the help of instrument-technological simulation of the silicon-on-insulator field-effect Hall sensor (SOI FEHS) in the partial depletion mode, the effect of increasing its magnetic sensitivity was discovered. In this paper, we study the parameters of SOI-FEHS samples in various operation modes to experimentally confirm the discovered effect. To increase the measurement accuracy in the partial depletion mode, the FEHS design with a split drain is used. The optimal values ​​of the load resistances of the bridge circuit are determined. An analysis of the results of studying the experimental SOI-FEHS samples shows that the peak of the increased magnetic sensitivity is observed in the partial depletion mode. At a load resistance of 1 MΩ and a supply voltage of –9 V, the maximal magnetically induced signal approximately triples in the partial depletion mode compared with the full depletion mode. When recalculating the ΔU voltage difference on the load resistances to the magnetic sensitivity, the specific magnetic sensitivity of the FEHS in the partial depletion mode can reach values ​​of about 105 V/(A T), which is significantly higher than that of semiconductor Hall elements.

Comparison and analysis of multiple signal processing methods in steel wire rope defect detection by hall sensor

Steel wire rope (SWR) defect signal processing techniques and methods are the key to exact defect detection and identification, which is important in guaranteeing human lives and property. But the inspection signals sensed by the commonly used inductive coil sensor are often susceptible to the detector’s scanning speed, wire rope shaking and vibration, whereas they are unaffected when induced by hall element sensor. Thus, the experiments for wire rope local fault (LF) of broken wire inspection by hall sensors and magnetic flux leakage (MFL) testing method are conducted, and different groups of original signals are obtained. Then, performances of multiple signal processing methods are compared and evaluated in the perspective of baseline drift elimination and signal denoising. Besides, the main impact parameters in these signal processing methods are investigated and revealed. Finally, comparisons and discussions for different filtering methods are analyzed and presented.

Ultrasensitive Magnetic Sensors Enabled by Heterogeneous Integration of Graphene Hall Elements and Silicon Processing Circuits.

Graphene Hall elements (GHEs) have been demonstrated to be promising magnetic field sensors with excellent sensitivity, linearity, temperature stability, and compatibility with complementary-metal-oxide-semiconductor (CMOS)-integrated circuits (ICs). However, the demonstrated GHEs have still not exhibited a comprehensive advantage in performance over commercial integrated Hall sensors which were implemented in integrated Hall element and CMOS processing ICs. In this work, we develop a technology for the three-dimensional (3D) heterogeneous integration of silicon-based CMOS ICs and GHEs, and the fabricated magnetic field sensors outperform commercial high-end integrated Hall sensors. Specifically, the integrated Hall sensors are implemented in a stacked integration on Si based on a chopper programmable-gain amplifier (CPGA), a chopper-stabilized second-order sigma-delta modulator (CSDM), and graphene-based Hall elements on monochips. GHEs with high sensitivity (up to 1000 A/VT) are fabricated with a compatible process on a smoothened silicon nitride passivation layer of silicon-based CMOS ICs, and the two device layers are connected by an interlayer. The heterogeneous integrated Hall ICs exhibit current and voltage magnetic sensitivities up to 64 000 A/VT and 6.12 V/VT, respectively, which are much higher than those in all other reported nanomaterial-based Hall sensors and even in high-end commercial Hall ICs. Furthermore, the 3D heterogeneous integration technology used here can be extended as a universal technology for integrating nanomaterial-based sensors and Si CMOS ICs.

A Review of Wire Rope Detection Methods, Sensors and Signal Processing Techniques

Wire rope inspection by nondestructive testing methods, sensors and signal processing techniques are mainly reviewed in this paper. Owing to the difference of physical mechanism and testing principles, magnetic flux leakage, eddy current, acoustic emission and ultrasonic guide wave testing as well as other inspection methods for steel wire rope are summarized. Then, the commonly and frequently used testing sensors of inductive coil, hall element, magnetoresistive sensors and others are compared in the perspective of their corresponding operating principles, development situation, advantages and disadvantages. Furthermore, signal processing techniques including the signal filtering techniques such as the time and frequency analysis methods, quantitative data processing methods such as the machine learning and defect classification are studied. Finally, the challenges and future developing trends of wire rope inspection in practical applications are discussed.

A Stray-Field-Immune Magnetic Displacement Sensor With 1% Accuracy

We present a new Hall sensor design for the accurate and robust measurement of linear displacement. Implemented in CMOS, the sensor is based on a novel gradient measurement concept combining Hall elements with integrated magnetic concentrators. In typical applications with practical Ferrite magnets, the peak output voltage of the Hall transducers is only around 1.7 mV at the maximum operating temperature of 160°C, and thus requires high-performance low-offset readout electronics. Over its 15-mm linear displacement range, the sensor’s total error is 1% including manufacturing tolerances, trimming accuracy, temperature, aging effects, and practical magnet constraints. In addition, the sensor is immune to magnetic stray fields up to 5 mT, complying with the most stringent automotive norm.

The performance limits of epigraphene Hall sensors doped across the Dirac point

Epitaxial graphene on silicon carbide, or epigraphene, provides an excellent platform for Hall sensing devices in terms of both high electrical quality and scalability. However, the challenge in controlling its carrier density has thus far prevented systematic studies of epigraphene Hall sensor performance. In this work, we investigate epigraphene Hall sensors where epigraphene is doped across the Dirac point using molecular doping. Depending on the carrier density, molecular-doped epigraphene Hall sensors reach room temperature sensitivities of SV = 0.23 V/(VT) and SI = 1440 V/(AT), with magnetic field detection limits down to BMIN = 27 nT/√Hz at 20 kHz. Thermally stabilized devices demonstrate operation up to 150 °C with SV = 0.12 V/(VT), SI = 300 V/(AT), and BMIN ∼100 nT/√Hz at 20 kHz. Our work demonstrates that epigraphene doped close to the Dirac point could potentially outperform III–V Hall elements in the extended and military temperature ranges.

DEVELOPMENT GAUGE FOR CONTROL PARAMETERS RADIATION ELECTROMAGNETIC FIELDS

The subject study of the article is to measure electromagnetic fields to determine their impact on the human body. The article is research process develop measuring devices for monitoring parameters of radiation of electromagnetic fields. The problem to be solved – just ification of technical solutions and their implementation in practice allow accurate measurements to know the presence and location of malicious artificial electromagnetic radiation and the extent of their impact on the human body by applying a gauge to monitor the parameters of the radiation of electromagnetic fields. The paper considered: the structure of the device control parameters of the radiation of electromagnetic fields; studied the work of two-channel analog-to-digital converter; investigated electric circuit device using a Hall element and field instrumentation amplifier; investigated circuit input stage device using silicon element Hall and operational amplifier; investigated temperature compensation circuit with reference interchange power at the source voltage EX. Conclusion: The proposed technical solution should be used when developing the measuring device to control the parameters of the radiation of electromagnetic fields

Implementation of a graphene quantum Hall Kelvin bridge-on-a-chip for resistance calibrations

The unique properties of the quantum Hall effect allow one to revisit traditional measurement circuits with a new flavour. In this paper we present the first realization of a quantum Hall Kelvin bridge for the calibration of standard resistors directly against the quantum Hall resistance. The bridge design is particularly simple and requires a minimal number of instruments. The implementation here proposed is based on the bridge-on-a-chip, an integrated circuit composed of three graphene quantum Hall elements and superconducting wiring. The accuracy achieved in the calibration of a 12 906 standard resistor is of a few parts in 108, at present mainly limited by the prototype device and the interferences in the current implementation, with the potential to achieve few parts in 109, which is the level of the systematic uncertainty of the quantum Hall Kelvin bridge itself.

Broadband on-chip photonic spin Hall element via inverse design

The photonic spin Hall effect plays an important role in photonic information technologies, especially in on-chip spin Hall devices. However, conventional devices suffer from low efficiency or narrow bandwidth, which prevents their practical application. Here, we introduce a spin Hall device using inverse design to achieve both high efficiency and broadband. Spin-dependent light separation is enabled by a 2.4 μm circular device with 100 nm pixels. The photonic spin Hall element is fabricated on a silicon-on-insulator wafer compatible with a standard integrated photonic circuit. The spin light is detected and emitted with an efficiency of up to 22% and 35%, respectively, over a 200 nm bandwidth at optical wavelength.