Magnetic Hall Sensors Research Articles

SISTEM KOMUNIKASI JARAK JAUH ALAT PENGUKUR KECEPATAN DAN ARAH ANGIN

The process of measuring wind speed and its direction is still manual and considered inefficient. The purpose of making these tools is to help get the data of speed and direction of the wind from a distance in order to work more eficient. In determining the wind speed is done by chopping round of the wind speed sensor by using an encoder while the determination of the wind direction is done by reading the orientation of magnetic hall sensor, constructed as wind direction. Utilizing the Arduino Mega 2560 Microcontroller as controller, the data is recorded with a cycle which can be set. The data that has been recorded is sent to Sim900a GSM shield in the form of SMS. Then the data is received by GSM shield the server and sent to the computer. The results of this system is able to measure and store data speed and direction of the wind from a distance. With a wind speed error of 4. 56% of the measurements manually, and wind direction indicates the actual wind direction.

Sistem Komunikasi Jarak Jauh Alat Pengukur Kecepatan Dan Arah Angin Berbasis Mikrokontroller

Monitoring wind speed and direction is usually performed at close range, therefore,it is necessaryto monitor remotely for time efficiencies. Making these systems start with a literature study the data relating to the technology to be used. Then the data was processed to determine the design of the system being designed. Making this system begins with a measuring instrument wind speed and wind direction. In this device for chopping round of the wind speed sensor using optocoupler. And magnetic hall sensor, constructed as a weathervane as a determinant of the wind direction sensor. RTC is used as time refference of measurement. Arduino Mega 2560 Microcontroller used to process data obtained from sensors and RTC. Then the data is the data is recorded with a cycle which can be set. After the manufacture of measuring devices and then proceed to make the data transmission system and application interface. With GSM shield Sim900a data that has been recorded is sent in the form of SMS through GSM network. Then the data is received by GSM shield servers and read by Arduino UNO. Data is read by Arduino UNO is then sent to a computer with serial communication. The data is sent to the computer will be processed by the application interface to be stored and displayed. The results of this system is able to measure and store data speed and direction of the wind from a distance. With a windspeed error of 4.56% of the measurements manually, and wind direction indicates the actual wind direction.

A Novel Closed Loop Current Sensor Based on a Circular Array of Magnetic Field Sensors

During the last years, coreless current sensors based on circular arrays of magnetic field sensors have been investigated. These sensors were limited in bandwidth and accuracy by the magnetic field sensors used to realize the circular arrays. Thus, this paper applied the well-known “closed loop” principle to circular array-based current sensors to overcome these limitations. This paper gives a comparison between circular arrays built from Hall and Fluxgate magnetic field sensors in both the closed loop and open loop operation. If closed loop configuration Fluxgate sensors are used, instead of Hall sensors, the measurement error can be reduced by a factor of two due to their intrinsic characteristics. Moreover, it is shown that the closed loop operation of the circular arrays results in a significant reduction of the temperature drift of the sensitivity for Fluxgate and Hall sensor-based circular arrays. If Hall sensors are used for the circular array, the reduction of the temperature drift of the sensitivity achieved by closed loop operation is about a factor of 10. If Fluxgate sensors are used, a significant reduction of the nonlinearities like hysteresis and a substantial reduction of the temperature drift of the sensitivity was observed.

Low-Voltage-Operated Highly Sensitive Graphene Hall Elements by Ionic Gating.

The advanced Hall magnetic sensor using an ion-gated graphene field-effect transistor demonstrates a high current-normalized sensitivity larger than 3000 V/AT and low operation voltages smaller than 0.5 V. From commercially available graphene-on-SiO2 wafers, large-area arrays of ion-gated graphene Hall element (ig-GHE) samples are prepared through complementary metal-oxide-semiconductor-compatible fabrication processes except the final addition of ionic liquid electrolyte covering the exposed graphene channel and the separate gate-electrode area. The enhanced carrier tunability by ionic gating enables this ig-GHE device to be extremely sensitive to magnetic fields in low-voltage-operation regimes. Further electrical characterization indicates that the operation window is limited by the nonuniform carrier concentration over the channel under high bias conditions. The drain-current-normalized magnetic resolution of the device measured using the low-frequency noise technique is comparable to the previously reported values despite its significant low power consumption.

Design and Simulation of a Novel Vertical Hall Sensor With High Negative Differential Sensitivity

We report on the design and simulation of a novel vertical Hall sensor, which exhibits highly nonlinear characteristics between Hall voltage and bias voltage, featuring a region of large negative differential sensitivity. Based on these features, novel techniques for exciting the Hall plate and for signal extraction are suggested, allowing for further enhancement of the residual offset-limited dc resolution of in-plane magnetic field-sensitive Hall sensors, in particular, and integrated three-dimensional Hall sensors, in general.

A Superpositioning Technique for Accurate Open-Type Current Sensing in Three-Phase Electrical Switchboards

Monitoring and analysis of power consumption are critical in terms of energy management, especially when managing the energy of factories with high energy consumption equipment. Hall sensors can be used for monitoring the power consumption. In this paper, we propose a novel superpositioning method for use with the three-phase current lines of an electrical switchboard, to improve the accuracy of current sensing by distinguishing the wanted magnetic field from magnetic interference. The relationship between magnetic interference and the magnetic field which we are trying to measure was investigated quantitatively by using numerical simulations as well as an experimental measurement. We subsequently designed a CMOS system-on-chip for use with magnetic Hall sensors, for practical validation of the proposed method. With this technique, measurement errors were less than ±0.8 %, based on experiments conducted with 50 A flowing through a three-phase current switchboard.

Development of Magnetic Flux Leakage Robot for Large-Sized Tanks Bottom Floor

This study develops a wheeled robot with magnetic flux leakage testing device. This testing robot is designed to detect the corrosion-oriented defects on the bottom plates of large-sized tanks at petrochemical plants. A Hall-effect encoder is used to achieve the function of location detection. Besides, the magnetization device consists of NdFeB permanent magnets and silicon steel sheets, with the detection probe adopting Hall magnetic sensor. Experimental results show that the magnetic flux leakage testing device is highly reliable as it can accurately detect defects sized 2 mm and being 4 mm deep on the surface of a S20C steel plate being 10 mm thick. Besides, with a S20C steel plate being 5 mm thick, the device can detect defects sized 2 mm and being 2 mm deep on the front and reverse sides.

High magnetic field test of the ITER outer vessel steady-state magnetic field Hall sensors at ITER relevant temperature.

The ITER outer vessel steady-state magnetic field sensor diagnostics consist of sixty sensor units. Each sensor unit features a pair of ceramic-metal Hall sensors with a sensing layer made of bismuth. The sensors were tested simultaneously in the magnetic field ranging from -12 T to +12 T at the temperature range from 27 to 127 °C. The Hall coefficient and magnetoresistance of the bismuth layer related to the sensors were identified. In the sensor operating conditions, the Hall coefficient dependence on temperature was fitted with an exponential function with a relative error of less than 0.08%, and the dependence on the magnetic field was fitted with a Gaussian-like function with a relative error of less than 0.11%. An alternative expression based on the physical understanding of the free charge carrier transport in semimetals was derived to describe the dependence of the Hall coefficient on the magnetic field, and its fitting error of 1.2 mT in terms of the magnetic field measurement has met the ITER measurement accuracy requirements.

Ultrathin All‐in‐One Spin Hall Magnetic Sensor with Built‐In AC Excitation Enabled by Spin Current

AbstractMagnetoresistance (MR) sensors provide cost‐effective solutions for diverse industrial and consumer applications, including emerging fields such as internet‐of‐things (IoT), artificial intelligence, and smart living. Commercially available MR sensors such as anisotropic magnetoresistance (AMR) sensors, giant magnetoresistance (GMR) sensors, and tunnel magnetoresistance (TMR) sensors typically require an appropriate magnetic bias for both output linearization and noise suppression, resulting in increased structural complexity and manufacturing cost. Here, an all‐in‐one spin Hall magnetoresistance (SMR) sensor with built‐in AC excitation and rectification detection is demonstrated, which effectively eliminates the requirements of any linearization and domain stabilization mechanisms separated from the active sensing layer. This is made possible by the coexistence of SMR and spin–orbit torque (SOT) in ultrathin NiFe/Pt bilayers. Despite the simplest possible structure, the fabricated Wheatstone bridge sensor exhibits essentially zero DC offset, negligible hysteresis, and a detectivity of around 1 nT Hz−1/2 at 1 Hz. In addition, it also shows an angle dependence to external field similar to those of GMR and TMR, though it does not have any reference layer (unlike GMR and TMR). The superior performances of SMR sensors are evidently demonstrated in the proof‐of‐concept experiments on rotation angle measurement, and vibration and finger motion detection.

Hall sensors batch-fabricated on all-CVD h-BN/graphene/h-BN heterostructures

The two-dimensional (2D) material graphene is highly promising for Hall sensors due to its potential of having high charge carrier mobility and low carrier concentration at room temperature. Here, we report the scalable batch-fabrication of magnetic Hall sensors on graphene encapsulated in hexagonal boron nitride (h-BN) using commercially available large area CVD grown materials. The all-CVD grown h-BN/graphene/h-BN van der Waals heterostructures were prepared by layer transfer technique and Hall sensors were batch-fabricated with 1D edge metal contacts. The current-related Hall sensitivities up to 97 V/AT are measured at room temperature. The Hall sensors showed robust performance over the wafer scale with stable characteristics over six months in ambient environment. This work opens avenues for further development of growth and fabrication technologies of all-CVD 2D material heterostructures and allows further improvements in Hall sensor performance for practical applications.

Localized detection of reversal nucleation generated by high moment magnetic nanoparticles using a large-area magnetic sensor

This report introduces a local-magnetic-reversal-nucleation based giant magnetoresistance (GMR) sensor with a large sensing area and further discusses its novel sensing scheme of high magnetic moment nanoparticles (MNPs). We demonstrated experimentally that this large-area GMR sensor could successfully detect high moment MNPs. The detection scheme of localized reversal nucleation of GMR sensor induced by MNPs was analyzed and further confirmed by the micromagnetic simulations. This work may provide one pathway in designing next generation GMR biosensors with large area and high sensitivity. This sensing scheme could be applicable to other magnetic biosensors such as magnetic tunnel junction sensors and planar Hall sensors.

Research of the Monolithic Integrated 3-D Magnetic Field Sensor Based on MEMS Technology

A monolithic-integrated 3-D magnetic field sensor is proposed in this paper, which is composed of four silicon magnetic sensitive transistors and a Hall magnetic field sensor. Using microelectromechanical system (MEMS) technology, the chip of the sensor was designed and fabricated on a p-type silicon wafer with a higher resistivity. At the room temperature, the magnetic sensitivities $S_{xx}$ and $S_{yy}$ on the $x$ - and $y$ -directions are 77.5 and 78.6 mV/T at power supply $V_{DD}= 5.0$ V and base injection current $I_{b}= 1.0$ mA, respectively. In addition, the magnetic sensitivity $S_{zz}$ on the $z$ -axis is 77.4 mV/T at $V_{DD}= 5.0$ V. The experimental results show that the proposed sensor has a good uniformity of magnetic sensitivity, besides achieving the measurement to 3-D magnetic fields and the cross sensitivities are less than 3% at $B\le 0.8$ T.

Gate-tunable Hall sensors on large area CVD graphene protected by h-BN with 1D edge contacts

Graphene is an excellent material for Hall sensors due to its atomically thin structure, high carrier mobility, and low carrier density. However, graphene devices need to be protected from the environment for reliable and durable performance in different environmental conditions. Here we present magnetic Hall sensors fabricated on large area commercially available chemical vapor deposited (CVD) graphene protected by exfoliated hexagonal boron nitride (h-BN). To connect the graphene active regions of Hall samples to the outputs, 1D edge contacts were utilized which show reliable and stable electrical properties. The operation of the Hall sensors shows the current-related sensitivity up to 345 V/(AT). By changing the carrier concentration and type in graphene by the application of gate voltage, we are able to tune the Hall sensitivity.

Signal conditioning and processing for metallic Hall sensors

Two electronics prototypes for the ITER outer vessel steady-state magnetic field Hall sensors based on a lock-in signal processing and current spinning technique were developed. The prototypes, the first using a rectangular lock-in signal processing with sensor offset cancellation and the second employing advanced lock-in signal processing with sensor and electronics offset cancellation, were compared with a DC technique and commercial lock-in amplifier. The influence of long interconnection cables, white noise, and interfering planar Hall effect to a measurement accuracy was evaluated. The planar Hall voltage suppression by the current spinning technique was investigated. Whilst the rectangular lock-in amplifier prototype failed to meet the ITER accuracy requirement, the advanced lock-in amplifier prototype demonstrated required functionality and accuracy.

An overview of commercially available Teslameters for applications in modern science and industry

<p>The Hall-effect based Teslameters (also called Gaussmeters) are the mostly applied instruments for measuring DC and AC magnetic flux densities in modern science and industry. This paper gives an overview of commercially available Teslameters at the high-end performance level. The Teslameters have been evaluated by following characteristics that are published by suppliers: probe dimensions, magnetic field sensitive volume, accuracy, magnetic resolution, measurement range, frequency bandwidth, temperature coefficient sensitivity, and price/performance ratio.</p><p>The Teslameter that best matches the measurement needs in various application fields incorporates a 3-axis integrated Hall probe, analog electronics based on the spinning-current technique, an analog-to-digital converter, an embedded computer, and a touch-screen display. The 3-axis Hall probe is a single silicon chip integrating both horizontal and vertical Hall magnetic sensors and a temperature sensor. The spinning-current eliminates most of the Hall probe offset, low-frequency noise, and the planar Hall voltage. The errors due to the Hall sensor non-linearity and the variations in the probe and electronics temperatures are eliminated by a calibration procedure. The errors due to the angular imperfections of the Hall probe are eliminated by a calibration of the sensitivity tensor of the probe. This Teslameter can measure magnetic field vectors from about 100 nT to 30 T, with the spatial resolution of 100 µm, magnetic resolution ±2 ppm of the range, the accuracy 0.002 % of the range, a temperature coefficient less than 5 ppm/°C, and angular errors less than 0.1°.</p>

A Monolithic CMOS Magnetic Hall Sensor with High Sensitivity and Linearity Characteristics.

This paper presents a fully integrated linear Hall sensor by means of 0.8 μm high voltage complementary metal-oxide semiconductor (CMOS) technology. This monolithic Hall sensor chip features a highly sensitive horizontal switched Hall plate and an efficient signal conditioner using dynamic offset cancellation technique. An improved cross-like Hall plate achieves high magnetic sensitivity and low offset. A new spinning current modulator stabilizes the quiescent output voltage and improves the reliability of the signal conditioner. The tested results show that at the 5 V supply voltage, the maximum Hall output voltage of the monolithic Hall sensor microsystem, is up to ±2.1 V and the linearity of Hall output voltage is higher than 99% in the magnetic flux density range from ±5 mT to ±175 mT. The output equivalent residual offset is 0.48 mT and the static power consumption is 20 mW.

High-accuracy teslameter with thin high-resolution three-axis Hall probe

The new digital teslameter system (also called Gaussmeter) incorporates a 3-axis Hall probe, analog electronics based on the spinning-current technique, 24-bit analog-to-digital converter, computer, and 7-digit touch-screen display. The Hall probe is a single silicon chip with monolithically integrated horizontal and vertical Hall magnetic sensors and a temperature sensor. The Hall sensor chip is encapsulated in a robust ceramic package, a version of which is only 250 μm thick. The spinning-current eliminates most of the Hall probe offset, low-frequency noise, and the planar Hall voltage. The errors due to the Hall element non-linearity and the variations in the probe electronics temperatures are eliminated by a calibration procedure based on a three-variable second-order polynomial. The errors due to the angular errors of the Hall probe are eliminated by a calibration of the sensitivity tensor of the probe. These new developments resulted in a teslameter that can measure magnetic field vectors from about 1 μT to 30 T, with the spatial resolution 100 μm, magnetic resolution ±2 ppm of the range, the accuracy ±0.0001% of reading +0.001% of range, temperature coefficient less than 5 ppm/°C, and angular errors less than 0.1 deg.

A magnetic force sensor on a catheter tip for minimally invasive surgery.

This paper presents a magnetically guided catheter for minimally invasive surgery (MIS) with a magnetic force sensing tip. The force sensing element utilizes a magnetic Hall sensor and a miniature permanent magnet mounted on a flexible encapsulation acting as the sensing membrane. It is capable of high sensitivity and robust force measurements suitable for in-vivo applications. A second larger magnet placed on the catheter allows the catheter to be guided by applying magnetic fields. Precise orientation control can be achieved with an external magnetic manipulation system. The proposed device can be used in many applications of minimally invasive surgery (MIS) to detect forces applied on tissue during procedures or to characterize different types of tissue for diagnosis.

Magnetic-particle-sensing based diagnostic protocols and applications.

Magnetic particle-labeled biomaterial detection has attracted much attention in recent years for a number of reasons; easy manipulation by external magnetic fields, easy functionalization of the surface, and large surface-to-volume ratio, to name but a few. In this review, we report on our recent investigations into the detection of nano-sized magnetic particles. First, the detection by Hall magnetic sensor with lock-in amplifier and alternative magnetic field is summarized. Then, our approach to detect sub-200 nm diameter target magnetic particles via relatively large micoro-sized “columnar particles” by optical microscopy is described. Subsequently, we summarize magnetic particle detection based on optical techniques; one method is based on the scattering of the magnetically-assembled nano-sized magnetic bead chain in rotating magnetic fields and the other one is based on the reflection of magnetic target particles and porous silicon. Finally, we report recent works with reference to more familiar industrial products (such as smartphone-based medical diagnosis systems and magnetic removal of unspecific-binded nano-sized particles, or “magnetic washing”).

Effects of Hall Output Probes Shape on Magnetic Characterization of Hall Magnetic Field Sensor Based on MOSFET

This paper presents the effects of Hall output probes shape on the magnetic characteristic of magnetic field sensors with Hall output probes, which is based on metal-oxide-semiconductor field effect transistor (MOSFET). The Hall sensor chips are fabricated on <100> silicon substrates with high resistivity by using CMOS technology. Experiment results show that, when drain-source voltage VDS=5.0 V, the magnetic sensitivity of the magnetic field sensor with the concave Hall output probes and channel length-width ratios of 160 μm/80 μm, 320 μm/80 μm and 480 μm/80 μm are 53.3 mV/T, 32.54 mV/T and 20.32 mV/T, respectively. At the same condition, the magnetic sensitivity of the magnetic field sensor with convex Hall output probes and the channel length-width ratio of 160 μm/80 μm is 76.8 mV/T.