Magnetoelectric Sensors Research Articles

Study of Target Penetration Feature Extraction and Signal Antialiasing Performance Based on Magnetoelectric Sensor

Study of Target Penetration Feature Extraction and Signal Antialiasing Performance Based on Magnetoelectric Sensor

Enhanced detection performance based on a differential ME sensor with strong suppression of vibration interference

Magnetoelectric (ME) sensors have enormous potential for detecting weak magnetic fields because of their high sensitivity, low power consumption, compact size and, low cost. However, inevitable vibration interference limits their application in practical environments, especially in the case of mobile platform mounting. Here, we propose a differential ME sensor, consisting of PZT macro-fiber composites (MFCs) and Metglas laminates. The differential ME sensor has two output terminals with weak mutual mechanical coupling and works in longitudinal vibration mode. MFC cores are polarized in parallel mode to guarantee their consistency of electric characteristics and reversed bias field is provided by attached magnets. Experimental results show that the differential-mode response amplitudes have a gain of −17.6 dB for low-frequency vibration at 2 Hz and ∼6.2 dB for an applied magnetic field at 3 Hz, in comparison with the single-ended mode. In addition, our proposed ME sensor also has a low inherent equivalent magnetic noise of 18.3 pT/√Hz at 1 Hz. Finally, a target detection experiment in the presence of heavy lab noise and strong vibration interference is conducted and the improved detection performance of the proposed differential ME sensor is proved.

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.

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.

Vibration stability of an ultra-high-resolution plane grating monochromator at HALF

The global requirement for grating monochromators with high precision and exceptional vibrational stability is crucial for diffraction-limited synchrotron radiation sources (DLSR). An ultra-high-spectral resolution plane grating monochromator (PGM) based on the stroke bearing shaft has been developed for Hefei Advanced Light Facility (HALF) at the National Synchrotron Radiation Laboratory (NSRL). A comprehensive performance evaluation of PGM is crucial prior to its online installation during the commissioning phase. Various vibration measurement tools were employed to meticulously characterize PGM stability. A magneto-electric velocity sensor is used to measure the vibration amplitude of the PGM components, and an optical encoder and laser interferometer are used to quantify the angular stability. The measured data are analyzed to determine the vibration source. Angular vibrations with different water-cooling conditions are compared. The PGM exhibited angular vibrations of approximately 30 nrad RMS (1–500 Hz, pitch direction), thereby satisfying the beamline requirements.

Strong magnetoelectric coupling in novel Na0.5Bi0.5TiO3–BaFe12-2xCoxTixO19 multiferroic composite

Multiferroic composites of sol-gel synthesized Sodium Bismuth Titanate (Na0.5Bi0.5TiO3) and Co–Ti substituted Barium Hexaferrite (BaFe12-2xCoxTixO19; x = 0.0, 0.5, 1.0, 1.5 and 2.0) in the ratio 3:1 was synthesized through ceramic route. Successful formation of R3c rhombohedral and P63/mmc hexagonal phases corresponding to Na0.5Bi0.5TiO3 and BaFe12-2xCoxTixO19 respectively was confirmed from the XRD and Rietveld refinement pattern. The frequency and temperature dependence of dielectric constant and loss of the composite systems exhibited typical dispersion behaviour which could be understood using the Maxwell-Wagner model. Substituted samples showed enhanced dielectric behaviour where dielectric constant was observed to increase while loss tangent decreased. Using the Universal Jonscher's Power law (JPL), conductivition mechanisms of the composite systems were studied from the ac conductivity behaviour which revealed that the x = 0.0 sample followed Non-overlapping Small Polaron Tunnelling (NSPT) model while the remaining samples followed the Correlated Barrier Hopping (CBH) model. The complex impedance and Nyquist plot analysis showed the enhancement of resistive property in the x≠0 systems. Magnetic hysteresis loop measurements were conducted, and the associated parameters were determined with the assistance of the Law of Approach to Saturation (LAS). Favourable reduction in the magnetic anisotropy was observed indicating the disturbance of magnetic spin structure in the hexaferrite phase. The P-E loops established the novel room temperature multiferroic nature of the composite systems. Significant magnetoelectric coupling was detected at room temperature in all samples, with the x = 0.5 sample exhibiting the highest value of approximately 59.81 mV/cmOe. These desirable properties suggest that the composites may find future device applications as in magnetically tunable energy harvesting devices and self-powered magnetoelectric sensors in the future.

Relatively Low‐Frequency Magnetic Field Detection System Using Metglas/PZT‐5B Sensor

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.

Contactless Magnetoelectric Sensor Based on PVDF-TrFE and Metglass Laminates for Lithium-Ion Battery Current and Vibration Monitoring

Contactless Magnetoelectric Sensor Based on PVDF-TrFE and Metglass Laminates for Lithium-Ion Battery Current and Vibration Monitoring

A self-powered magnetoelectric 3D tactile sensor with adjustable sensitivity for robot arms

With the rapid development of robot arms in various industries, the interactions between the tip ends of robot arms and the target surfaces or objects play an important role. Tactile sensors, particularly for force measurement, are widely used at the tip ends of robot arms for information exchange. Currently, most of the tactile sensors used at the tip ends of robot arms are with one planar or arc sensing surface (2D sensing area), which can only measure the contact force when the surfaces or objects are facing the sensing surface (around 180° working space range). However, contact forces may come from any direction (360° working space range), which needs tactile sensors with 3D sensing area to measure multi-direction contact forces. To tackle this problem, a self-powered magnetoelectric 3D tactile sensor (SM3D-TS) is proposed in this paper. Firstly, the design and fabrication of the SM3D-TS are described in detail. Secondly, the mechanical properties of the SM3D-TS are tested. Thirdly, the voltage-force relationship of the SM3D-TS is calibrated in single direction. Then, the force measuring and random points positioning performances are validated. Without power input, the SM3D-TS can measure contact forces from multiple directions with speed-dependent sensitivity. The experimental results show that the SM3D-TS can not only accurately measure the contact forces at given speed by independently using the induced voltages in the three axes, but also can position random points at given contact speed with high accuracy.

In Situ Test and Numerical Analysis of the Subway-Induced Vibration Influence in Historical and Cultural Reserves.

Although the rapid expansion of urban rail transit offers convenience to citizens, the issue of subway vibration cannot be overlooked. This study investigates the spatial distribution characteristics of vibration in the Fayuan Temple historic and cultural reserve. It involves using a V001 magnetoelectric acceleration sensor capable of monitoring low amplitudes with a sensitivity of 0.298 V/(m/s2), a measuring range of up to 20 m/s2, and a frequency range span from 0.5 to 100 Hz for in situ testing, analyzing the law of vibration propagation in this area, evaluating the impact on buildings, and determining the vibration reduction scheme. The reserve is divided into three zones based on the vertical vibration level measured during the in situ test as follows: severely excessive, generally excessive, and non-excessive vibration. Furthermore, the research develops a dynamic coupling model of vehicle-track-tunnel-stratum-structure to verify the damping effect of the wire spring floating plate track and periodic pile row. It compares the characteristics of three vibration reduction schemes, namely, internal vibration reduction reconstruction, periodic pile row, and anti-vibration reinforcement or reconstruction of buildings, proposing a comprehensive solution. Considering the construction conditions, difficulty, cost, and other factors, a periodic pile row is recommended as the primary treatment measure. If necessary, anti-vibration reinforcement or reconstruction of buildings can serve as supplemental measures.

A flexible magneto-electric sensor with enhanced performance through flower-shaped BTO fillers in P(VDF-TrFE) matrix

A flexible magneto-electric(ME) sensor, incorporated a piezoelectric layer with flower-shaped Barium Titanate (BTO) fillers(referred as BTFs) in P(VDF-TrFE) matrix and a ferromagnetic Metglas layer[P(VDF-TrFE)@BTFs/Metglas], has been developed. The introduction of flower-shaped BTO fillers enhances the β-phase of P(VDF-TrFE), leading to improved piezoelectric properties. The unique flower-like structure provides a larger specific surface area and increased grain size, resulting in interface asymmetry and creating a more intricate contact interface between P(VDF-TrFE) and Metglas. This strengthens the interaction and facilitates strain transmission, ultimately enhancing the ME coupling performance of the system. Moreover, the flexible ME detector exhibits superior magnetic field detection capabilities, demonstrating enhanced sensitivity and resolution compared to its spherical BTO counterpart. The devices display exceptional linearity, indicating the potential for practical application as magnetic sensors. This research expands the understanding of the complex relationship between filler morphology and P(VDF-TrFE) properties, presenting promising potential for high-performance flexible ME devices.

Low-noise inverse magnetoelectric magnetic field sensor

In the development of any type of magnetic field sensor based on magnetic films, special consideration must be given to the magnetic layer component. The presented work investigates the use of scalable flux closing magnetostrictive multilayers for inverse magnetoelectric sensors. In such a type of magnetic field sensor, highly sensitive AC and DC field detection relies on strong excitation of the incorporated magnetic layers by piezoelectrically driven cantilever oscillation at mechanical resonances. The provoked periodic flux change is influenced by the magnetic field to be measured and is picked up by a coil, which generates the measured output. The multilayered inverse magnetoelectric sensor is investigated with regard to linearity, noise behavior, and detection limit of DC and AC signals. A significant advancement for inverse magnetoelectric thin film sensors is demonstrated in this study. Using exchange bias stabilized magnetic multilayers with flux closure structures, detection limits are improved by an order of magnitude to less than 8 pT/Hz1/2 at 10 Hz and 18 pT/Hz1/2 at DC.

Magnetoelectric Sensor Operating in d15 Thickness-Shear Mode for High-Frequency Current Detection.

For the application of high-frequency current detection in power systems, such as very fast transient current, lightning current, partial discharge pulse current, etc., current sensors with a quick response are indispensable. Here, we propose a high-frequency magnetoelectric current sensor, which consists of a PZT piezoelectric ceramic and Metglas amorphous alloy. The proposed sensor is designed to work under d15 thickness-shear mode, with the resonant frequency around 1.029 MHz. Furthermore, the proposed sensor is fabricated as a high-frequency magnetoelectric current sensor. A comparative experiment is carried out between the tunnel magnetoresistance sensor and the magnetoelectric sensor, in the aspect of high-frequency current detection up to 3 MHz. Our experimental results demonstrate that the d15 thickness-shear mode magnetoelectric sensor has great potential for high-frequency current detection in smart grids.

A Combined Magnetoelectric Sensor Array and MRI-Based Human Head Model for Biomagnetic FEM Simulation and Sensor Crosstalk Analysis.

Magnetoelectric (ME) magnetic field sensors are novel sensing devices of great interest in the field of biomagnetic measurements. We investigate the influence of magnetic crosstalk and the linearity of the response of ME sensors in different array and excitation configurations. To achieve this aim, we introduce a combined multiscale 3D finite-element method (FEM) model consisting of an array of 15 ME sensors and an MRI-based human head model with three approximated compartments of biological tissues for skin, skull, and white matter. A linearized material model at the small-signal working point is assumed. We apply homogeneous magnetic fields and perform inhomogeneous magnetic field excitation for the ME sensors by placing an electric point dipole source inside the head. Our findings indicate significant magnetic crosstalk between adjacent sensors leading down to a 15.6% lower magnetic response at a close distance of 5 mm and an increasing sensor response with diminishing crosstalk effects at increasing distances up to 5 cm. The outermost sensors in the array exhibit significantly less crosstalk than the sensors located in the center of the array, and the vertically adjacent sensors exhibit a stronger crosstalk effect than the horizontally adjacent ones. Furthermore, we calculate the ratio between the electric and magnetic sensor responses as the sensitivity value and find near-constant sensitivities for each sensor, confirming a linear relationship despite magnetic crosstalk and the potential to simulate excitation sources and sensor responses independently.

A Wide-Band Magnetoelectric Sensor Based on a Negative-Feedback Compensated Readout Circuit.

Magnetoelectric (ME) sensors cannot effectively detect broadband magnetic field signals due to their narrow bandwidth, and existing readout circuits are unable to vary the bandwidth of the sensors. To expand the bandwidth, this paper introduces a negative-feedback readout circuit, fabricated by introducing a negative-feedback compensation circuit based on the direct readout circuit of the ME sensor. The negative-feedback compensation circuit contains a current amplifier, a feedback resistor, and a feedback coil. For this purpose, a Metglas/PVDF/Metglas ME sensor was prepared. Experimental measurements show that there is a six-fold difference between the maximum and minimum values of the ME voltage coefficients in the 6-39 kHz frequency band for the ME sensor without the negative-feedback compensation circuit when the sensor operates at the optimal bias magnetic field. However, the ME voltage coefficient in this band remains stable, at 900 V/T, after the charge amplification of the direct-reading circuit and the negative-feedback circuit. In addition, experimental results show that this negative-feedback readout circuit does not increase the equivalent magnetic noise of the sensor, with a noise level of 240 pT/√Hz in the frequency band lower than 25 kHz, 63 pT/√Hz around the resonance frequency of 30 kHz, and 620 pT/√Hz at 39 kHz. This paper proposes a negative-feedback readout circuit based on the direct readout circuit, which greatly increases the bandwidth of ME sensors and promotes the widespread application of ME sensors in the fields of broadband weak magnetic signal detection and DBS electrode positioning.

A Novel E-E Type Electrically Modulated Magnetoelectric Sensor for Extremely Low Frequency Magnetic Field Detection

A Novel E-E Type Electrically Modulated Magnetoelectric Sensor for Extremely Low Frequency Magnetic Field Detection

Additively Manufactured Flexible Liquid Metal-Coated Self-Powered Magnetoelectric Sensors with High Design Freedom.

Although additive manufacturing enables controllable structural design and customized performance for magnetoelectric sensors, their design and fabrication still require careful matching of the size and modulus between the magnetic and conductive components. Achieving magnetoelectric integration remains challenging, and the rigid coils limit the flexibility of the sensors. To overcome these obstacles, this study proposes a composite process combining selective laser sintering (SLS) and 3D transfer printing for fabricating flexible liquid metal-coated magnetoelectric sensors. The liquid metal forms a conformal conductive network on the SLS-printed magnetic lattice structure. Deformation of the structure alters the magnetic flux passing through it, thereby generating voltage. A reverse model segmentation and summation method is established to calculate the theoretical magnetic flux. The impact of the volume fraction, unit size, and height of the sensors on the voltage is studied, and optimization of these factors yields a maximum voltage of 45.6 µV. The sensor has excellent sensing performance with a sensitivity of 10.9kPa-1 and a minimum detection pressure of 0.1kPa. The voltage can be generated through various external forces. This work presents a significant advancement in fabricating liquid metal-based magnetoelectric sensors by improving their structural flexibility, magnetoelectric integration, and design freedom.

A self-powered magnetoelectric tactile sensor for material recognition

Due to the complex working environments, robots need to sense and react to their various interactive surroundings with the help of tactile perception. Material recognition, one of the basic applications of tactile perception, can be achieved by further interpreting and representing the tactile data collected by tactile sensors. Suitable control strategies can be implemented to ensure stable and efficient operation of robots if the contacting materials are accurately recognized. Therefore, in this paper, a soft, deformable, and self-powered tactile sensor based on magnetoelectric materials is developed. Structural design, working principles, and shape optimization of this magnetoelectric tactile sensor are first described. Fabrication and assembly of the magnetoelectric tactile sensor are then introduced. The material recognition experiments including the voltage ratio ranges study, test 1 (velocity change), and test 2 (size and shape change) are performed to validate the effectiveness of the proposed magnetoelectric tactile sensor. The experimental results show that the recognition accuracy is high (around 90% for soft materials and 100% for hard materials) regardless of sizes and shapes of the contacting materials.

A Combined Magnetoelectric Sensor and Human Head Model for Biomagnetic FEM Simulations

A Combined Magnetoelectric Sensor and Human Head Model for Biomagnetic FEM Simulations

High SNR magnetoelectric sensor with dual working modes for wideband magnetic field detection

Magnetoelectric (ME) composites exhibit extremely high sensitivity for magnetic field at the fixed resonant frequency, due to the strong strain-mediated ME coupling. However, wideband magnetic field detection is still challenging, as the ME coefficient depends strongly on the frequency. In this work, we propose a magnetoelectric sensor composed of three ME units in series/parallel connections, which works at dual modes to extend the frequency range with high signal-to-noise ratio (SNR). The SNR is enhanced by about 22.68 dB and the bandwidth is broadened from 100 Hz to 1 kHz, with a high sensitivity for frequency conversion mode by series/parallel connections. Limits of detections (LoDs) as low as 207 pT and 460 pT are demonstrated at 1 kHz and 100 kHz, respectively, showing promising applications in wideband magnetic field detection.