Induced Magnetoelectric Voltage Research Articles

Differential configuration of 180° anti-phase-modulated nonlinear magnetoelectric effect of parallel-placed dual FeNiMoSiB/Pb(Zr1−xTix)O3 composites for magnetic field sensing

Magnetic sensors based on nonlinear magnetoelectric (ME) effect can be used to measure weak dc and ac magnetic fields at room temperature. The focus of this paper is to present the nonlinear ME effect of parallel-placed dual FeNiMoSiB/PZT/FeNiMoSiB composites with small size which are operated in 180° anti-phase modulated mode and differential output configuration. In this design, the strong ME voltage at even order harmonics due to frequency doubling effect of magnetostriction is greatly attenuated. This is of great benefit to the design of the sensor signal conditioning circuit because strong even order harmonics limit the magnification of the first stage amplifier. Due to the nonlinear ME effect, the induced ME voltage of the odd order harmonics is modulated by a weak dc/ac magnetic field to be measured. The wideband frequency of weak magnetic field from dc-0.9f (f is the frequency of the driving field) can be recovered from the 1 st harmonic response by the lock-in demodulation method. The sensitivity and limit of detection of the anti-phase modulated differential ME dual-unit are 176.1 μV/μT and 2 nT/√Hz at 10 Hz, respectively.

A Magentoelectric Coefficient Measurement System with a Free-Stress Sample Holder

With less extra stress on the testing sample, a free-stress sample holder was designed to place the sample horizontally. With the free-stress sample holder, a magnetoelectric (ME) coefficient measurement system was developed based on dynamic method. This measurement system has the hardware part and the software part, integrated by the DC magnetic field generation module, the AC magnetic field generation module, the induced ME voltage detecting module and PC software module. Then, a sample of Terfenol-D/PZT/Terfenol-D trilayer was designed and fabricated, and the relationships of its ME coefficient influenced by the DC magnetic field and the frequency of the AC magnetic field were tested using the measurement system. And the results showed that the free-stress sample holder was proven to improve the accuracy of the measurement system by less stress interference.

Enhanced self-bias magnetoelectric effect in locally heat-treated ME laminated composite

This study reports the improvement in the magnetoelectric (ME) coupling effect in a locally heat-treated FeBSi (Metglas)/Pb(Mg1/3Nb2/3)O3-PbZrO3-PbTiO3 single crystal laminated composite under zero magnetic bias. The high-temperature pulse laser treatment could induce local crystallization along the laser scanning line, but adjacent domains remained still amorphous, which resulted in the thermal and lattice mismatch. Therefore, it could produce a residual stress between the crystalline and amorphous phases, which generated an internal bias field in the Metglas foil. The experimental results showed that the ME coefficient for the laser-treated laminate was enhanced to 1220 V/cm Oe at the resonance frequency of 23.32 kHz without a magnetic bias, which was two times higher than that of the untreated ME laminates. The induced ME voltage also showed a linear response to the applied AC magnetic field with an amplitude as low as 10−10 T at the resonance. The excellent ME performance could, therefore, serve as a promising and practicable application for highly sensitive magnetic field sensors under the zero bias field.

Flexible magnetoelectric transducer with high magnetic field sensitivity based on Metglas/poly(vinylidene fluoride) heterostructures

In this paper, the flexible magnetoelectric (ME) transducer consisting of FeSiB (Metglas)/poly(vinylidene fluoride) (PVDF) is presented, whose ME coupling characteristics and ME sensing performance under different bend status have been investigated. It is found that an appropriate size of transducers is propitious to the ME coupling characteristics due to the demagnetization effect. In addition, with increase the bending angle (θ) of transducers from 0° to 50°, the magnetoelectric voltage coefficient (MEVC) shows a reduction from 240.42 to 26.44 V/cm·Oe and 13.1 to 2.11 V/cm·Oe, at the resonance and low-frequency (1 kHz), respectively. Meanwhile, the induced ME voltage have an excellent linear relationship to ac magnetic field. An ultrahigh magnetic field sensitivity of 1.22 V/Oe and 0.11 V/Oe have been found under θ = 0° and 50°, respectively, which are positively comparable to the highest reported in the most recent polymer-based ME transducers. Moreover, the transducers can maintain the MEVC stable after an additionally bending cycles up to 1000 times, indicating the full flexibility and high stability of the mentioned transducers. Obviously, it demonstrates that the proposed FeSiB/PVDF transducers have great potential of being applied to wearable devices.

Self-biased magnetoelectric effect in (Pb, Zr)TiO3/metglas laminates by annealing method

FeBSiC metglas was annealed at an optimized condition (350°C, 5min) to achieve the mixed phases with pristine amorphous phase and crystallization phase. With such annealed metglas, a self-biased magnetoelectric (ME) laminate of metglas/Pb(Zr, Ti)O3/metglas was fabricated. Without any external magnetic field, the composite exhibits the ME coefficient αE31 of 103mV/(cm Oe) at 1kHz and 15.5V/(cm Oe) at electromechanical resonance frequency. The induced ME voltage shows a good linear relation to the applied AC magnetic field with amplitude as low as 10−7T at 1kHz. It is expected that such self-biased ME composites provide a practical application of economical and compact magnetic sensors.

Note: High sensitivity self-bias magnetoelectric sensor with two different magnetostrictive materials

The self-bias magnetoelectric (ME) sensor is designed, fabricated, and characterized for detecting weak ac magnetic-field. The two different magnetostrictive materials produce the gradient of magnetization, resulting in an internal magnetic field and a strong ME response. At zero-biased dc magnetic field, a low-frequency ME voltage coefficient (dVME∕dHac) of 22.11 mV∕Oe is achieved, which is 17.69 times higher than that of the previous magnets∕0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (PMN-PT) sensor. Furthermore, the ME voltage coefficient reaches 2.73 V∕Oe at resonance. The induced ME voltage shows an excellent linear relationship to ac magnetic field when field amplitude varies from ~10(-7) Oe to 1 Oe.

Multiferroic composite for combined detection of static and alternating magnetic fields

Magneto-electric (ME) effects in bi-layer multiferroics consisting of single crystal hexagonal SrAl xFe 12 − x O 19 ferrites (hexaferrites, where x = 0, 0.8, 1.2) and PbZrTiO 3 (PZT) have been studied. The main objective of the study was to determine the effect of the Al doping concentration on the ME coupling. We experimentally demonstrate that the Al doping improves dramatically the magnetically induced ME voltage. Moreover, our data indicate that the ME response is a linear function of both ac and dc applied magnetic fields. This is in contrast to previously reported multiferroic laminates that show a non-linear magneto-electric induced voltage as a function of the applied dc magnetic field. The multiferroic structures reported in this work have therefore enhanced functionality because they can linearly operate as a dual ac/dc magnetic field sensors.

Large magnetoelectric effect from mechanically mediated magnetic field-induced strain effect in Ni–Mn–Ga single crystal and piezoelectric effect in PVDF polymer

Abstract Magnetoelectric (ME) effect is observed in a bilayered composite fabricated by laminating one ferromagnetic shape memory Ni–Mn–Ga single-crystal plate with one piezoelectric PVDF polymer film. The reported ME effect originates from the mechanically mediated magnetic field-induced strain effect in the Ni–Mn–Ga plate and piezoelectric effect in the PVDF film. The induced ME voltage shows a good linear response to the applied ac magnetic field in the field range of 0–5 Oe. A large ME coefficient ( α E ) of 1.24 V/(cm Oe) is obtained at an optimal bias magnetic field of 5.1 kOe due to the reversible reorientation of martensitic twin variants in the Ni–Mn–Ga plate. Based on the combination of pseudo-piezomagnetism in the Ni–Mn–Ga plate and piezoelectricity in the PVDF film, the ME effect in the bilayered composite is predicted and found to agree with the experimental results.

Giant magnetoelectric effect in mechanically clamped heterostructures of magnetostrictive alloy and piezoelectric crystal-alloy cymbal

We experimentally and theoretically report a giant magnetoelectric (ME) effect in a heterostructure made by clamping a bar-shaped magnetostrictive Tb0.3Dy0.7Fe1.92 (Terfenol-D) alloy actuator and a cymbal-type piezoelectric 0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3(PMN–PT) (PMN-PT) single crystal-brass alloy transducer in a brass alloy frame. The reported ME effect originates from the stress-mediated product of the magnetostrictive effect in the Terfenol-D bar actuator and the mechanically transformed/amplified piezoelectric effect in the PMN PT-brass cymbal transducer under mechanically clamped conditions. The heterostructure exhibits a giant ME voltage coefficient (αV) of 440mV∕Oe at an optimal magnetic bias field of 400Oe besides showing good linearity between the induced ME voltage and the applied ac magnetic field in the field range of 10−3–10Oe. This αV is larger than that of conventional Terfenol-D/PMN-PT laminated composites.

High magnetoelectric effect in laminated composites of giant magnetostrictive alloy and lead-free piezoelectric ceramic

Magnetoelectric (ME) laminated composites with all phases environmentally friendly were prepared by sandwiching one layer of thickness-polarized (Bi1∕2Na1∕2)TiO3-(Bi1∕2K1∕2)TiO3-BaTiO3 lead-free piezoelectric ceramic disk between two layers of thickness-magnetized Tb0.3Dy0.7Fe1.92 giant magnetostrictive alloy disk along the thickness direction. The composites exhibited the maximum ME voltage coefficient of 40.7 mV/Oe with a flat response in the measured frequency range of 0.1−20 kHz under a dc magnetic bias of 5 kOe. The induced ME voltage showed an extremely linear relationship to the applied ac magnetic field with amplitude varying from 3×10−5 to 10 Oe over a broad range of dc magnetic bias of 0−5.5 kOe. The high ME effect was analyzed and found to be comparable to most major lead-based ME composites. The present study opens up possibilities for developing green ME devices.

Magnetoelectric effect in laminate composite of magnets/0.7Pb(Mg1∕3Nb2∕3)O3–0.3PbTiO3 single crystal

A magnetoelectric (ME) laminate composite was fabricated by sandwiching one 0.7Pb(Mg1∕3Nb2∕3)O3–0.3PbTiO3 (PMN-PT) piezoelectric single crystal layer between two NdFeB magnet layers along the thickness direction. The high ME effect was obtained by the product of the magnetic attractive-repellent effect in the magnet layers and the piezoelectric effect in the piezoelectric layer. The magnetoelectric voltage coefficient of the composite was measured to be ∼12.5mV∕cmOe with a flat frequency response in the range of 0.1–20kHz. The induced ME voltage showed an excellent linear relationship to the applied ac magnetic field with field amplitude varying from 10−3to10Oe. Other advantages included low heat generation, no bias magnetic field required, and high scale-down capability. These made the composite to be a promising ME material for realizing high-performance, small-size, and low-cost magnetic sensors.

Magnetoelectric coupling, efficiency, and voltage gain effect in piezoelectric-piezomagnetic laminate composites

The magnetoelectric (ME) effect of piezoelectric-magnetostrictive laminate composites, which is a product tensor, has been studied. Based on piezoelectric and piezomagnetic constituent equations, the longitudinal-mode vibration and equivalent circuits have been derived. The effective magnetoelectric coupling coefficient, voltage-gain, and output efficiency have been determined. Our results show: (i) that there is an extreme high voltage gain effect of >260 under resonance drive: the induced ME voltage is much higher than the input voltage to the coils for magnetic excitation; (ii) that there is an optimum ratio of the piezoelectric to piezomagnetic layer thicknesses, which results in maximum effective magnetoelectric coupling; and (iii) that the maximum output efficiency of magnetoelectric laminate at resonance drive is ∼98%, if eddy currents are neglected. This high ME voltage gain effect offers potential for power transformer applications.