Jingen Wu

Wide-range current sensors have extensive applications in power grid systems. Current sensing technologies predominantly rely on Hall-effect sensors, shunts, and transformers, which encounter technical challenges such as high-power consumption, intrusive measurement methods, elevated costs, and installation requiring outage, etc. In this work, we proposed a current sensor based on magnetoelectric coupling effect, which is made of the Terfenol-D/PMN-PT/Terfenol-D magnetoelectric composite. The proposed current sensor shows the resonance magnetoelectric coefficient of 21.32 V/(cm∙Oe) at 32.7 kHz, with the limit of detection (LOD) of 2.01 pT under resonance. Meanwhile, the linear range of the proposed sensor can be regulated by the DC bias magnetic field that provided by NdFeB permanent magnets. Due to the large magnetostrictive saturation of Terfenol-D, the proposed current sensor presents a large linear range for magnetic field detection. Also, the proposed current sensor has been verified to measure wide-range current from 0.8 mA to 1024 A, with a linear range spanning over four orders of magnitude, a sensitivity of 9.08 mV/A, and a nonlinearity error below 0.5 %FS, demonstrating significant potential in wide-range and high-precision current detection.

In this work, we modulate the performance of magnetoelectric (ME) composites by introducing residual stresses during their preparation. During the bonding and curing of magnetostrictive and piezoelectric materials, we stretch the magnetostrictive materials by applying a constant DC magnetic field. When curing is complete, the withdrawal of the DC magnetic field causes the magnetostrictive material to shrink and introduces residual stresses in the ME composite. This causes the ME composite to form a small curvature in the lengthwise direction, which alters the efficiency of stress–strain transfer. The magnitude of residual stress can be tuned by applying different DC magnetic fields to optimize the performance of ME composites. The effectiveness of this preparation method can also be verified by finite element analysis. The experimental results show that the ME coupling coefficient of the ME composite with a bending vibration mode is increased from 275 to 481 V/cm/Oe by the optimization of the residual stress regulation, while the limit of detection remains at a good state. This work could provide an effective method for performance enhancement of low-frequency ME sensors and promote the practical application of ME sensors.

High-sensitivity detection technology for low-frequency characteristic magnetic signals is urgently needed in fields such as power grid inspection, industrial fault detection, and geological exploration. Magnetoelectric (ME) sensors, owing to their resonance enhancement characteristics, are suitable for detecting weak magnetic signals at specific frequencies. This work enhances the performance of bending mode magnetoelectric resonators through variable section structure design and develops an equivalent circuit model based on a segmentation method to rapidly calculate their theoretical performance. Experimental results verify the model’s validity, further refining the theoretical model of ME resonators and facilitating their practical applications. The study provides a rapid calculation method suitable for variable section structures and a novel design approach for developing ME sensors operating in low-frequency bending vibration mode.

Calibration is essential to three-axis magnetometers in most applications. Typically, ellipsoid calibration method considers a sensor’s positive sensitive directions along its geometric axes as default, which may lead to inaccurate in sensitivities and misalignments. In this work, we propose a modified ellipsoid calibration algorithm to eliminate such indeterminacy. A three-axis magnetometer comprised of anisotropic magnetoresistive sensors and 3D printed structure was calibrated to prove the effectiveness of proposed method. And it realized 1.68° and 3.94° average errors of azimuth and elevation, respectively, for spatial DC magnetic field angle detection. Also, we demonstrate a two-step method for angle resolving, and a Monte Carlo simulation method for calibration performance prediction based on uncertainties. The proposed method reveals significant potential for calibration and evaluation of three-axis magnetometers.

A multiple-coupling optimization strategy was proposed to enhance the power density of an MME-EH. The optimized MME-EH with a compact volume of 0.97 cm³ achieved a record-high output power density of 0.73 mW cm⁻³ Oe⁻².

The constitutive relationships between electric dipole at unit cell scale and macroscopic ferroelectricity are revealed by the proposed matrix transformation model, where the theoretical S – E and P – E loops are coincident with the experimental results.

High sensitivity and low power consumption dc magnetic field sensors are crucial for advancing various technological fields, including portable magnetometers, condition monitoring of energy system, and geophysical exploration. However, achieving high sensitivity while maintaining low power consumption remains a challenge for dc magnetic field sensors. Here, we demonstrate an electric excitation dc magnetic field sensor based on (1-1) connective magnetoelectric (ME) composite, which consists of amorphous FeBSiC alloy (Metglas) and thickness-poled piezoelectric (PZT) transformer. The theoretical analyses based on finite element simulation methods reveal that the strong magnetic-flux-concentration effect and stress aggregation effect in (1-1) connective ME composite can enhance the elastic modulus change of magnetic material on mechanical stress transfer of piezoelectric transformer, thus improving the sensitivity for dc magnetic field detection. Experimental results verified that the sensor achieved a sensitivity of 120 mV/Oe, and a limit of detection (LOD) of 20 nT under an ultra-low power consumption of 86 μW within a dc magnetic field range of 0–3 Oe, representing a significant advancement in electric excitation (coil-free) dc magnetic field detection. This article demonstrates the potential of combining PZT transformer with magnetostriction materials for dc magnetic field detection.

The development of advanced magnetoelectric (ME) composites necessitates high-performance materials that are capable of achieving high levels of ME coupling, minimal magnetic loss, and absence or limited reliance on external excitation sources. In this paper, a (2-2) connectivity ME laminate integrates multiple layers of FeSiB alloy (Metglas) and Pb (Mg, Nb) O₃-PbTiO₃ (PMN-PT) single crystal, achieving a remarkable ME coupling coefficient of 2033.4 V/Oe·cm (sevenfold rise) by laser thermal annealing treatment. Here, the laser-induced nanostructures on Metglas, with an oxidized insulation layer and soft and hard magnetic dipole layer improve the Magneto-electric-mechanical coupling with a mechanical quality factor (Q_m) exceeding 350. More importantly, the interaction between amorphous and nanocrystalline dipoles triggers an Exchange Bias (EB) effect, leading to a self-biasing performance of 67.45 V/Oe·cm. Furthermore, the composite exhibits an excellent passive DC magnetic detection limit of 22 nT, and an improved weak AC magnetic detection limit down to 383 fT. These explorations offer the potential to enhance passive current measurement, and underwater communication, extend weak magnetic positioning and brain magnetic detection.