•We propose a self-biased high-sensitivity magnetostrictive/piezoelectric magnetoelectric (ME) heterostructure operating in shear mode.•A negative shear force as well as large internal anisotropic field is provided by SmFe2 plate due to its ferromagnetic and magnetostrictive properties.•Relationship between the shear-mode driving force and ME coefficients is analyzed.•This proposed laminate can be used in magnetic field detecting and energy harvesting without permanent magnets.We report on a shear-mode off-antiresonance and antiresonance magnetoelectric (ME) responses in Tb0.3Dy0.7Fe1.92/Pb(Zr, Ti)O3/SmFe2 laminate multiferroic heterostructures for magnetic detecting and energy scavenging without bias field. A negative shear force as well as large internal anisotropic field is provided by SmFe2 plate due to its ferromagnetic and magnetostrictive properties, while the Terfenol-D plate provides a positive shear force to provoke a higher shear–stress transfer. Consequently, stronger ME coupling with a value of 2.24 V/Oe is obtained to be generated from the proposed architecture in the absence of the applied dc magnetic field. Experimental results exhibit an approximately linear sensitivity curve under off-antiresonance and antiresonance conditions, and the minimum stepped variations of input ac magnetic field as low as 2.43 × 10−8 T can be clearly distinguished under 111.5 kHz. In addition, a maximum power of 0.323 μW with a 2.6 MΩ load resistance in series connected to the ME laminate under the conditions of no bias can be achieved. These properties demonstrate that such a miniature multimode ME device is capable of weak magnetic field detecting and spatial magnetic energy scavenging by removing the requirement of dc bias field.

This paper presents a piezoelectric energy harvester for scavenging AC magnetic field energy from an electric power line based on the Ampere's law. The harvester employs a piezoelectric cantilever beam with a magnetic circuit attached to the free end of the beam. The magnetic circuit uses three NdFeB magnets connected by two magnetic yokes in series, which produces an enhanced magnetic flux density on the power line. Consequently, more AC magnetic field energy from the current-carrying power line can be converted into electrical energy using the piezoelectric cantilever beam. In the theoretical analysis, the integral of the magnetic flux density produced by the magnetic circuit along the power line is expressed by a power series of the transverse displacement of the magnetic circuit, and a nonlinear modal equation of motion is derived. The equation is solved by the Linstedt–Poincaré method. The expressions of the steady-state output voltage and power are obtained based on the assumed model. The experimental results are in good agreement with the analytical results. Under the resonant frequency of 50 Hz, the harvester can generate a power of 1.58 mW with a matching load resistance of 216 kΩ at an AC current of 6 A.Highlights► We propose a piezoelectric energy harvester for scavenging energy from a power line based on the Ampere's law. ► The harvester employs a novel magnetic circuit mounted on the free end of a piezoelectric cantilever beam. ► The magnetic circuit produces an enhanced magnetic flux density on the power line. ► More energy from the power line can be converted into electrical energy using the cantilever beam. ► An analytical model is developed to predict the output voltage and power, and the theory matches the experiment well.

•We propose a wide-bandwidth high-sensitivity magnetostrictive/piezoelectric magnetoelectric (ME) composite.•Methods for the resonant ME effects in laminate composites under adjustable bias voltages are presented.•Relationships between control voltage, strain, Young's modulus, first-order resonant frequency and resonant ME coefficient are analyzed.•An analytical model is developed to predict the ME coefficients and resonant frequencies.•This composite can be used in magnetoelectric transducer and energy harvesting.This paper presents a wide-bandwidth high-sensitivity magnetostrictive/piezoelectric magnetoelectric (ME) composite (PZT-5/Terfenol-D/PZT-8). The resonant frequencies of the ME laminate structure can be adjusted by modulating the bias voltage across PZT-5 layer. Model and methods for the resonant ME effects in laminate composites under adjustable bias voltages are presented. The relationships between the control voltage, the strain, the Young's modulus, the first-order resonant frequencies and the resonant ME coefficient are analyzed. Theoretical analyses show that the first-order resonant frequencies of the laminate structure are almost a linear function of the applied dc bias voltage at a small strain. The ME coefficient is hardly related to the control voltage. The experimental results are in good agreement with the analytical results. For a control voltage of ±170 V, the first-order resonant frequencies can be linearly adjusted. The adjusted maximum of the resonant frequency is 1 kHz. The ratio of the adjusted value to the bias control voltage is 2.94 Hz/V. For the larger control voltage (such as ±350 V), the wider adjusted resonant frequency (over 2 kHz or 1.73%) can be obtained. Thus, the ME composite with a high sensitivity and a wide frequency bandwidth can be used in ME transducer and energy harvesting.

A high sensitivity magnetoelectric (ME) composite sensor employing a type of ferromagnetic constant-elasticity alloy (FeNi-FACE), piezoelectric Pb(Zr,Ti)O3 (PZT-8H) and high-permeability FeCuNbSiB (Fe73.5Cu1Nb3Si13.5B9) is developed. The FeCuNbSiB ribbon with the high permeability serves as the dynamic driver to increase the effective piezomagnetic coefficient d33 of the FeNi-FACE. At the same time, the FeCuNbSiB/FeNi-FACE/PZT-8H/FeNi-FACE/FeCuNbSiB (FeFPFFe) composite sensor exhibits a higher effective mechanical quality factor (Qm), which is ∼7.7 times higher than that of Terfenol-D/PZT-8H/Terfenol-D (MPM) sensor. As the ME voltage at resonance is directly proportional to the product of piezomagnetic coefficient and Qm, a stronger ME effect can be achieved. The experimental results show that the resonance ME voltage coefficient (MEVC) of the FeFPFFe sensor at Hdc = 119 Oe achieves 4.367 V/Oe, which is ∼1.41 times higher than that of FeNi-FACE/PZT-8H/FeNi-FACE (FPF) sensor. Furthermore, ∂VME/∂Hdc∂VME/∂Hdc for the FeFPFFe sensor achieves ∼22.5 m V/Oe at Hdc = 31 Oe under resonant drive conditions of Hac = 0.1 Oe, which is ∼20 times higher than that of the previous reported Terfenol-D/Pb(Zr,Ti)O3/Terfenol-D composite transducer. Thus the FeFPFFe sensor has highly sensitive ac or dc magnetic field sensing.Research highlights► A novel magnetoelectric sensor based on FeFPFFe laminate is designed, fabricated and characterized. ► The ME voltage as a function of Hdc for the FeFPFFe sensor under the resonance frequency is observed. ► The induced ME voltage of the FeFPFFe sensor at the resonant frequency as a function of ac magnetic field is measured. ► The experimental results show that the FeFPFFe sensor exhibits a high sensitivity to small variations in both ac and dc magnetic fields.

This paper presents an electromagnetic energy harvesting scheme by using a composite magnetoelectric (ME) transducer and a power management circuit. In the transducer, the vibrating wave induced from the magnetostrictive Terfenol-D plate in dynamic magnetic field is converged by using an ultrasonic horn. Consequently more vibrating energy can be converted into electricity by the piezoelectric element. A switching capacitor network for storing electricity is developed. The output of the transducer charges the storage capacitors in parallel until the voltage across the capacitors arrives at the threshold, and then the capacitors are automatically switched to being in series. More capacitors can be employed in the capacitor network to further raise the output voltage in discharging. For the weak magnetic field environment, an active magnetic generator and a magnetic coil antenna under ground are used for producing an ac magnetic field of 0.2–1 Oe at a distance of 25–50 m. In combination with the supply management circuit, the electromagnetic energy harvester with a rather weak power output (about 20 μW) under an ac magnetic field of 1 Oe can supply power for wireless sensor nodes with power consumption of 75 mW at a duration of 620 ms.