Resonance Magnetoelectric Effect Research Articles

Resonance magnetoelectric effect in a three-layer non-symmetric ring structure Ni/PZT/Metglas

The resonant magnetoelectric (ME) effect in a ring-type structure of nickel–lead zirconate titanate–Metglas amorphous alloy (Metglas 2605SA1) has been studied. The use of ring geometry and magnetic layers with different signs of magnetostriction and comparable saturation fields led to a noticeable enhancement in the ME coefficient and a decrease in the optimal bias field, as compared with two-layer planar heterostructures. At the frequency of radial acoustic oscillations of the structure and under circular magnetization, the ME coefficient of 6.4 V (Oe·cm)−1 and ac field sensitivity of 0.6 V Oe−1 were obtained for a permanent bias field of 2 Oe.

Resonant Magnetoelectric Coupling of Fe-Si-B/Pb(Zr,Ti)O3 Laminated Composites with Surface Crystalline Layers.

The resonant magnetoelectric (ME) effect of Fe78Si9B13/Pb(Zr,Ti)O3 (FeSiB/PZT) composites with a surface-modified Fe78Si9B13 amorphous alloy has been studied. The surface-modified FeSiB can improve the ME coefficient at the resonant frequency by optimizing the magnetomechancial power conversion efficiency. The maximum ME coefficient of the surface-modified ribbons combined with soft PZT (PZT5) is two-thirds larger than that of the composites with fully amorphous ribbons. Meanwhile, the maximum value of the ME coefficient with surface-modified FeSiB ribbons and hard PZT (PZT8) is one-third higher compared with the fully amorphous composites. In addition, experimental results of magnetomechanical coupling properties of FeSiB/PZT composites with or without piezoelectric layers indicate that the power efficiency of the composites first decreases and then increases with the increase in the number of FeSiB layers. When the surface crystalline FeSiB ribbons are combined with a commercially available hard piezoelectric ceramic plate, the maximum magnetoelectric coupling coefficient of the ME composite reaches 5522 V/(Oe*cm), of which the electromechanical resonant frequency is 23.89 kHz.

Reduced resonance frequency and enhanced coupling coefficient in fishtailing magnetoelectric resonator

Reducing the resonance frequency of the first-order longitudinal vibration mode for a bulk magnetoelectric (ME) resonator has been a challenge for very low frequency (VLF) magnetic sensing and transmitting application. In this work, we design and fabricate a fishtailing ME resonator that reduces the anti-resonance frequency from 18.8 to 12.2 kHz and the resonance frequency from 18.2 to 11.5 kHz compared with conventional 1–1 typed resonator. Meanwhile, a significant enhancement of the resonant ME coupling coefficient [from ∼8271 to ∼11 400 V/(cm Oe)] is also realized. Finite element simulation and lumped mass method are used to calculate and analyze the principles of the reduced resonance frequency and the reasons for enhanced coupling performance. The geometry tailoring method in this work is believed to inspire applications of the resonant ME effect at very low frequency.

Low-Frequency Resonant Magnetoelectric Effects in Layered Heterostructures Antiferromagnet-Piezoelectric

Magnetic field sensors using magnetoelectric (ME) effects in planar ferromagnetic-piezoelectric heterostructures convert a magnetic field into an output voltage. The parameters of ME sensors are determined by characteristics of the magnetic constituent. In this work, the low-frequency ME effects in heterostructures comprising a layer of antiferromagnetic hematite α-Fe2O3 crystal with easy-plane anisotropy and a piezoelectric layer are studied. The effects arise due to a combination of magnetostriction and piezoelectricity because of mechanical coupling of the layers. The field dependences of magnetization and magnetostriction of the hematite crystal are measured. The resonant ME effects in the hematite-piezopolymer and hematite-piezoceramic structures are studied. The strong coupling between magnetic and acoustic subsystems of hematite results in a tuning of the acoustic resonance frequency by the magnetic field. For the hematite layer, the frequency tuning was found to be ~37% with an increase in the bias field up to 600 Oe. For the hematite-PVDF heterostructure, the frequency tuning reached ~24% and the ME coefficient was 58 mV/(Oe∙cm). For the hematite-piezoceramic heterostructure, the frequency tuning was ~4.4% and the ME coefficient 4.8 V/(Oe∙cm). Efficient generation of the second voltage harmonic in the hematite-piezoceramic heterostructure was observed.

Low-frequency resonant magnetoelectric effects in a planar heterostructure of ferromagnetic yttrium iron garnet film and piezoelectric quartz

Low-frequency resonant magnetoelectric (ME) effects in a planar heterostructure containing a 50 μm thick single-crystal film of yttrium iron garnet (YIG) and a crystalline quartz platelet were studied. The ME effects in the mechanically coupled composite arise due to a combination of magnetostriction of the YIG film and the piezoelectric effect in quartz. The effects manifest as mutual transformation of ac magnetic and electric fields. When the layered composite was excited by an ac magnetic field (direct ME effect) at a planar acoustic resonance frequency of 128 kHz, the ME field conversion coefficient was 8.8 V/(Oe∙cm). When excited by an ac electric field (converse effect), the ME conversion coefficient was 0.32 G/(V/cm). Nonlinear ME effects caused by the nonlinear magnetostriction of the YIG film were observed as frequency doubling upon excitation of the direct ME effect by a magnetic field at a frequency equal to half the resonant frequency, as well as at the converse ME effect upon excitation by an electric field at the frequency of the resonance of the structure. In spite of weak magnetostriction for YIG, the resonant ME effects in the YIG-quartz composite are comparable in magnitude to the effects in composites with high magnetostriction materials, show high quality factor of Q ∼ 2200 and are observed in weak magnetic fields H ∼ 0–60 Oe. These results demonstrate the potential for YIG film-quartz composites application in electronic devices.

Resonance magnetoelectric effect analysis and output power optimization of nonlinear magnetoelectric transducer model

Magnetoelectric composites comprised of piezoelectric and magnetostrictive materials, are widely used in magnetic field sensing, energy harvesting, and transducers. This work establishes a finite element model of a laminated magnetoelectric transducer coupled with magneto-elastic-electric fields based on the constitutive equation of the nonlinear magnetostrictive material. Then, the resonant magnetoelectric effect under different biased magnetic fields is studied. Based on the equivalent circuit model and the two-port network theory, the magnetoelectric coefficient and the equivalent source impedance under the resonant state are completely solved for the first time. Introducing optimized L-section matching networks between the magnetoelectric transducer and the load resistor can increase the load power and expand the operating bandwidth. The simulation results are consistent with the data in the literature, thus confirming the accuracy and effectiveness of the model. The simulation results demonstrate that the magnetoelectric coefficient reaches 51.79 V/(cm·Oe) at 51.4 kHz and 450 Oe bias magnetic field, and the ultimate output power of –3.01 dBm at 50.4 kHz and 350 Oe bias magnetic field. To ensure the load power, the power increase of 2.30 dB and the bandwidth expansion of 2.27 times are achieved by optimizing the matching network. The nonlinear finite element model in this work takes into account of the magnetoelectric effect under the acoustic resonance state and quantifies the ultimate output power. The magnetoelectric transducer model can obtain high magnetoelectric coefficient, load power, and power density in a small volume, providing a significant advantage in terms of equilibrium. The research results are of great importance in guiding the design and performance improvement of miniaturized magnetically coupled wireless power transfer systems.

Magnetic field spectrum analyzer using nonlinear magnetoelectric effect in composite ferromagnet - piezoelectric heterostructure

Industrial machines and mechanisms, household appliances, natural sources and biological objects generate weak magnetic fields with amplitudes of ~10 –12 – 10 –4 T in the frequency band of ~1–10 5 Hz. Analysis of the fields’ characteristics allows to get information about internal processes and performance of these sources in a non-contact way, to carry out medical diagnostics. This makes topical the development of low-frequency magnetic field spectrum analyzers. The paper describes a spectrum analyzer of a new type using nonlinear effect of magnetic field mixing in a composite ferromagnet-piezoelectric heterostructure. The main element of the analyzer is a magnetic field mixer which contains a piezoelectric langatate single-crystal sandwiched between two layers of a magnetostrictive amorphous alloy. With simultaneous action of the measured magnetic field and the excitation magnetic field on the structure and fulfillment of the frequency matching conditions, the structure generates a voltage at the electromechanical resonance frequency. Swept-tuned spectrum analysis of the measured field is carried out by tuning the frequency of the excitation field. A prototype of the analyzer is fabricated and characterized. It operates in the frequency band of 0.1–85 kHz, has a frequency resolution of ~40 Hz, a minimum detectable field of 50 nT, and a dynamic range of 35 dB. Possibilities to improve characteristics of magnetic field spectrum analyzers are discussed. • A new swept-tuned spectrum analyzer of magnetic fields is proposed. • The analyzer uses resonant magnetoelectric effect of magnetic field frequency mixing. • A prototype of the spectrum analyzer is fabricated and characterized.

Magnetoelectric effects in stripe- and periodic heterostructures based on nickel–lead zirconate titanate bilayers

Objectives. A topical task in the design of magnetoelectric (ME) devices based on composite ferromagnetic– piezoelectric heterostructures involves reducing their dimensions to increase their operating frequencies and optimize their integration in modern electronics. The study set out to investigate the influence of in-plane dimensions on the characteristics of ME effects in stripe and periodic nickel–lead zirconate titanate heterostructures manufactured via electrolytic deposition.Methods. Lead zirconate titanate disks with Ag-electrodes were used for manufacturing the ME heterostructures; Ni was deposited on one Ag-electrode only.Results. While a reduction in stripe size leads to an increase in the frequency of the resonant ME effect, it is followed by a decrease in ME conversion efficiency. The ME coefficient for the periodic heterostructures is about ~1 V/(Oe·cm). By increasing the angle between the magnetic field H and the Ni-stripe axis from 0° to 90°, a 2.5-fold increase in the optimal field Hm and a 4-fold drop in the maximum amplitude of ME voltage umax(Hm) was achieved.Conclusions. In periodic heterostructures, the frequency of the resonant ME effect is determined by the substrate’s size, while ME conversion efficiency depends on the width of the Ni stripes and the distance between them. The observed anisotropy of the ME effects in the investigated heterostructures is explained in terms of demagnetization effects. In the future, the anisotropic ME effect in the periodic heterostructures could be used to develop magnetic field sensors that are sensitive to field orientation.

Theoretical analyses of magnetoelectric effects for magnetostrictive/radial mode piezoelectric transformer composite under dual ac stress and magnetic field modulation

Magnetoelectric (ME) composite based on the converse magnetoelectric (CME) effect is promising for the high sensitivity dc and low-frequency magnetic field detection application, however, the performance is restricted by the stress modulation ability of piezoelectric phases and the narrow bandwidth. This work presents a nonlinear equivalent circuit model to design a new ME composite consisting of magnetostrictive layers/radial mode piezoelectric transformer/magnetostrictive layers under dual ac magnetic field and stress modulation. The theoretical model is based on the nonlinear constitutive relationships of magnetostrictive material, motion equation with imperfect interface condition, and improved ME equivalent circuit. This model cannot only predict the resonant ME effects of electrically modulated ME composite under the dual ac stress and magnetic field drive, but can also predict the conventional CME and mutual inductance effects separately. Specifically, the theoretical prediction indicates that with negligible extra power consumption, the dual modulated ME composite provides higher dc and low-frequency magnetic field sensitivity with frequency conversion method and significantly wider bandwidth compared to the conventional CME effect. Such theoretical predictions are further verified by the experimental results of Metglas/piezoelectric transformer/Metglas and Terfenol-D/piezoelectric transformer/Terfenol-D laminate. The theoretical study plays a guiding role in designing the new ME magnetometer with low power consumption, high sensitivity, and wide bandwidth.

Theory of magnetic force driven magnetoelectric effect in piezo-bimorph/ferrite cantilever composite

A theoretical model is proposed for the frequency response of the magnetic force driven (MFD) magnetoelectric (ME) effect in a piezo-bimorph/ferrite cantilever based on the elastodynamics method, which agrees well with the experimental results for Pb(Zr, Ti)O3-bimorph/Mn–Zn-ferrite cantilever composites. Based on the theoretical model, the dependences of the resonant ME voltage coefficient on geometrical and material parameters of the piezo-bimorph/ferrite cantilever composite are numerically calculated. The results show that an optimum resonant ME effect can be achieved by adjusting the structural and material parameters in the piezo-bimorph/ferrite cantilever composite. This research lays a theoretical basis for understanding the resonant ME effect in the piezo-bimorph/ferrite composite and optimal design of the MFD-ME device based on this configuration.

Improved sensitivity and bandwidth of hybrid magnetic sensor based on electrically modulated amorphous magnetic alloy/piezoelectric composite

This study reports an electrically modulated dc and low frequency magnetic sensor with high sensitivity and wide bandwidth. It is based on multiferroic composites consisting of amorphous magnetic alloy Metglas/piezoelectric transformer (i.e., Pb(Zr,Ti)O3/Pb(Zr,Ti)O3)/Metglas layers winded with capacitor connected excitation coils and pickup coils. By electrically exciting the piezoelectric transformer winded with coils, the periodically induced stress and magnetic field modulate the magnetization of Metglas simultaneously and cause the change of magnetic flux within the pickup coils. The output voltage is further enhanced with the resonant converse magnetoelectric (CME) and mutual inductance effects at the mechanical and LC resonance frequency, respectively. Furthermore, the asymmetric wide bandwidth property of hybrid magnetic sensor provides the enhanced low frequency magnetic field sensitivity with negligible extra power consumption compared to the CME effect. When the magnetic sensors are excited with 5 V voltage at the resonance frequency and applied with 10 Hz magnetic field, the hybrid magnetic sensor achieves the maximum magnetic field sensitivity of 2.20 V/Oe and this is about 4.89 times as high as that of CME effect (0.45 V/Oe). The limit of detection for 10 Hz magnetic field is also noticeably improved from 2.97 nT for CME effect to 590pT for the hybrid magnetic sensor.

In-Plane Sizes Effects on Magnetoelectric Characteristics of a Ni-PZT Planar Heterostructure

Nowadays, the size reduction of electronic devices based on magnetoelectric (ME) effects is an important task. This will provide an opportunity for the wide integration of ME devices into modern microsystem technology. In this letter, the effects of in-plane sizes of planar heterostructures containing a ferromagnetic Ni film and a piezoelectric lead zirconate titanate (PZT) substrate on characteristics of the direct resonance ME effect are investigated. The Ni films of 10 μm in thickness were electrodeposited on the PZT substrates that were 200-μm-thick and 1.2-23 mm in length. The structures were placed in a permanent magnetic field and excited with an ac magnetic field. The generated ME voltage was measured at frequencies near planar acoustic resonances of the structures. For a 1.2 mm long structure, a frequency of 1380 kHz for in-plane acoustic resonance was achieved. A drop in the amplitude of the ME voltage was observed when the length of the structure became less than a critical value. Various mechanisms are discussed that lead to a voltage drop with a reduction of sizes of the structure, including the demagnetization effect, relaxation losses due to frequency dependence of the capacitance and resistance of the PZT layer, and an increase in acoustic losses.

Controlling the Characteristics of the Magnetoelectric Effect in Composite Resonators through External Actions

The possibility of controlling the characteristics of the low-frequency resonant magnetoelectric effect in composite structures using external effects is demonstrated. These composite structures contain ganged ferromagnetic and piezoelectric layers. The magnitude of the magnetoelectric effect in planar structures with layers of nickel and lead zirconate titanate changes by tens of percent, and the frequency of acoustic resonance is altered to ten percent under the action of a constant magnetic field or a constant electric field when the temperature changes or mechanical stresses are created in the structure.

Study on axial resonance magneto-electric (ME) effects of layered magneto-electric composites

An experimental investigation has been carried out to capture the magneto-mechanical behavior and material parameters of magnetostrictive material. Further, the experimental study is extended to capture the magnetoelectric (ME) coupling response of trilayered composites by applying both alternating and static magnetic fields. From the experiments, it is observed that the magnetostrictive material has a nonlinear hysteretic behavior. Hence, a three dimensional (3-D) nonlinear constitutive model has been proposed based on a thermodynamic framework and multisurface plasticity. In ME composites, it is also observed that a large ME coupling response can be obtained while operating near resonance frequencies. To capture the resonant ME effects, a theoretical formulation has been proposed based on axial vibrations theory and the proposed constitutive model has been incorporated in the formulation. The simulated resonant ME coupling response based on the proposed formulation is compared with the experimental data and found to be in agreement with each other. Further, a parametric study has been performed to address the variation of the resonant ME response as a function of various parameters such as axial compliance ratio, volume fraction of constituents, temperature, direction of magnetic loading and aspect ratio. This study reveals that the coupling response can be optimized by choosing the suitable parameters based on design requirement.

The effects of the soft magnetic alloys’ material characteristics on resonant magnetoelectric coupling for magnetostrictive/piezoelectric composites

The resonant magnetoelectric (ME) effects are investigated in Terfenol-D/PZT laminates with various soft magnetic alloys (i.e. FeCuNbSiB, FeSiB and CoNiFeSiB). The soft magnetic alloys with high magnetic permeability and magnetization produces an additional magnetostatic field in the Terfenol-D, which changes the effective magnetic field distribution within the Terfenol-D and plays an important role at the large zero bias ME response. Meanwhile, the magnetostrictive strain of soft magnetic alloys can produce a pre-stress on the Terfenol-D layer due to its low saturation field, which enhances the maximum ME voltage coefficient and reduces the required optimal dc magnetic field Hopt,dc. The experimental results indicate that the largest zero bias ME voltage coefficient is obtained for Terfenol-D/PZT composite with FeCuNbSiB (i.e. the soft magnetic alloy with the highest magnetization), which is about 7.3 times more than that of Terfenol-D/PZT at zero bias. The maximum ME voltage coefficient is obtained for Terfenol-D/PZT composite with FeSiB (i.e. the soft magnetic alloy with the largest magnetostriction constant) at Hopt,dc = 175 Oe, which is about 1.15 times greater than that of Terfenol-D/PZT composite (at Hopt,dc = 598 Oe) and also happens at a much smaller bias field.

Resonant magnetoelectronic effect with isolated magnetomechanical damping in meta-composite of quartz crystal resonator and magnetosrticive alloy

A novel magnetoelectric (ME) meta-composite device composed of a piezoelectric quartz crystal double-ended tuning fork (DETF), FeGa magnetostrictive plates, and quartz spacers is developed to realize low damping resonant ME effect. As the magnetostrictive force is transferred to the DETF through quartz spacers at the decoupling zones where the bending moments and shearing forces are cancelled out, the DETF is isolated from the magnetomechanical damping of FeGa plates. This improves the Q-factor of the meta-composite well. The device can be regarded as a driven damped system. Its resonance occurs when the frequency of the ac excitation magnetic field is around the resonant frequency of the DETF, producing enhanced response to finite ac magnetic field input. The magnetostrictive force induced by dc bias magnetic field leads to an increase of the resonance frequency of the DETF because of its force sensitive property. The sensitivity of ME current coefficient with respect to dc field is greatly enhanced at the selected operating frequencies around resonance due to the shift of resonance frequency as well as the amplification effect of Q-factor.

Studies on mechanical loss in converse magnetoelectric effect under multi-physical field

By means of the technic for measuring resonant converse magnetoelectric (CME) effect, the mechanical loss of PZT/Terfenol-D/PZT tri-layer symmetric magnetoelectric laminated composites under multi-physical field loads such as bias magnetic field, driven voltage and ambient temperature is systematically measured in this paper. The experimental results show that the mechanical loss in CME effect increases initially with the increase of the bias magnetic field, and approaches to a broad maximum value at 250–500 Oe. Further increasing bias magnetic field leads to the decrease of mechanical loss. The mechanical loss increases rapidly with the increase of driven voltage amplitude, especially in the medium magnitude of the bias magnetic field. While, there is little influence of voltage on the mechanical loss under the higher bias magnetic fields. Importantly, the mechanical loss increases monotonically as the increase of ambient temperature. The research results of the mechanical loss under multi-physics fields in this paper can provide a basic principle of CME improvement by reducing the mechanical loss. Therefore, this research is quite significant to the CME based applications, such as, magnetoelectric transducers, magnetoelectric microwave devices, multiferroic antennas and so on.

Influence of the ΔE Effect on the Field Dependence of the Magnetoelectric Effect in the Region of Electromechanical Resonance

The influence of the ΔE effect on the field dependence of the resonant magnetoelectric effect in bulk composite materials with a composition of ferrite nickel spinel–lead zirconate titanate has been investigated in the electromechanical resonance region. It has been shown that the field dependence of the effect is determined not only by the magnetic-field dependence of the piezomagnetic coefficient, but also by the field dependence of the Young modulus. The dependence of the resonance frequency of the effect on the bias field has been analyzed.

Temperature Dependence of the Resonant Magnetoelectric Effect in Layered Heterostructures.

The dependence of the resonant direct magnetoelectric effect on temperature is studied experimentally in planar composite structures. Samples of rectangular shapes with dimensions of 5 mm × 20 mm employed ferromagnetic layers of either an amorphous (metallic glass) alloy or nickel with a thickness of 20–200 μm and piezoelectric layers of single crystalline langatate material or lead zirconate titanate piezoelectric ceramics with a thickness of 500 μm. The temperature of the samples was varied in a range between 120 and 390 K by blowing a gaseous nitrogen stream around them. It is shown that the effective characteristics of the magnetoelectric effect—such as the mechanical resonance frequency fr, the quality factor Q and the magnitude of the magnetoelectric coefficient αE at the resonance frequency—are contingent on temperature. The interrelations between the temperature changes of the characteristics of the magnetoelectric effect and the temperature variations of the following material parameters—Young’s modulus Y, the acoustic quality factor of individual layers, the dielectric constant ε, the piezoelectric modulus d of the piezoelectric layer as well as the piezomagnetic coefficients λ(n) of the ferromagnetic layer—are established. The effect of temperature on the characteristics of the nonlinear magnetoelectric effect is observed for the first time. The results can be useful for designing magnetoelectric heterostructures with specified temperature characteristics, in particular, for the development of thermally stabilized magnetoelectric devices.

Modeling of Magnetoelectric Effects in Magnetostrictive/Piezoelectric Laminated Composites Using the Energy Method

The current models of the resonant magnetoelectric (ME) effect are based on Newton’s equation of motion and some given conditions which are various in published papers. Even some results are in conflict with Gauss’s law in magnetics. This paper provides the energy method to model ME effects. The energy method is based on linear constitutive equations and the principle of minimum energy. By constructing and solving the constraint problem of the variational principle, more reasonable conditions are deduced for simplifying Newton’s motion equation. The induced additional fields of externally applied fields are considered during the process of deducing by Gauss’s law for electricity or magnetism. The coefficients of direct/converse ME effects are obtained and compared with the models in the previous papers. The proposed model avoids conflict with Gauss’s law and provides another insight into understanding the resonant and static ME effects.