Electromechanical Resonance Frequency Research Articles

Synthesis and high-frequency magnetoelectric characterization of the 0–3 particulate lead-free multiferroic composite KNN/CFO

The research for lead-free magnetoelectric (ME) multiferroic composite materials has increased considerably because they are environmentally friendly. For composites with 0–3 connectivity, synthesis with lead-free phase has proven challenging to obtain high values of ME coupling. This work reports the successful synthesis of the KNN/CFO composite (K0.5N0.5NbO3/CoFe2O4) by conventional synthesis process. XRD and SEI showed two well-defined, also presenting good electric polarization values. The ME coefficient was very high, reaching values close to 2850 mV cm−1·Oe at the electromechanical resonance frequency. The dipolar interaction between the electric charges and magnetic moments of the KNN and CFO phases was responsible for the high value and the behavior of dependence on the applied magnetic field.

A Hybrid Actuator Model for Efficient Guided Wave based Structural Health Monitoring Simulations

Abstract Simulation has been recognized as a promising option to reduce the time and costs associated with determining Probability of Detection (POD) curves to demonstrate the performance of Guided Wave based Structural Health Monitoring (GW-SHM) systems. Time domain transient spectral finite element schemes have been used for large GW-SHM simulation campaigns, but the most common piezoelectric transducer model used for actuation, the pin force model, has limitations in terms of its range of validity. This is because the excitation frequency for the pin force model has only been validated far below the first electromechanical resonance frequency of the piezoelectric transducer mainly due to not considering the normal stress and dynamics of the transducer. As a result, the value of simulation tools for performance demonstrations may be limited. To address this limitation, this paper introduces a Hybrid Actuator Model that integrates frequency-dependent complex interfacial stresses in both the shear and normal directions, computed using finite elements. These surface stresses are compatible with time domain transient spectral finite element schemes, enabling their seamless integration without compromising the required performance for conducting intensive simulation campaigns. The proposed hybrid actuator model undergoes validation through a combination of simulation and experimental studies. Additionally, a comprehensive parametric study is conducted to assess the model's validity across a wide range of excitation frequencies. The results demonstrate the accurate representation of the transduction signal above the piezoelectric transducer's first free electromechanical resonance frequency.

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.

Superior temperature stability of electromechanical properties and resonant frequency in PYN-PZT piezoelectric ceramics

In this study, the Pb(Yb1/2Nb1/2)O3 (PYN) relaxor with high Curie temperature (TC ∼300 °C) was incorporated into PbZrO3-PbTiO3 (PZ-PT) ceramics to form 0.1PYN-(1-x)PZ-xPT ternary ceramics, and their phase compositions were systematically investigated, providing the more detailed phase diagrams, dielectric, piezoelectric, and ferroelectric properties. Excellent piezoelectric performance (d33 ∼ 450 pC/N, d33* ∼714 pm/V), with high coercive field (EC ∼17.5 kV/cm) and TC (∼398 °C) were simultaneously achieved in the 0.1PYN-0.41PZ-0.49PT composition near the morphotropic phase boundary (MPB). The value of d33 × EC, which exhibits higher than commercial PZT ceramics, indicates its suitability for high-field excitation devices. Additionally, the temperature stability of the resonant frequency (fr) is qualitatively studied by analyzing the main factors influencing fr from a theoretical perspective. Superior stability is achieved in the 0.1PYN-0.38PZ-0.52PT composition (TC ∼ 405 °C) with tetragonal phase, and the temperature coefficient of resonant frequency (Δfr /fr25 °C) remains within 0.5% up to 300 °C, far outperformance than previous reports.

Analysis of variance (anova) of the influence of molybdenum and cobalt additives on piezoelectric, dielectric and ferroelectric properties of Pb(Zr0.52Ti0.48)O3

This study aims to determine how molybdenum and cobalt additives affect the structural and electrical characteristics of Pb(Zr0.52Ti0.48)O3. by substituting zirconate and titanate with molybdenum and cobalt, individually or in combination, in the range of 0–2%. The powders were initially made in order to achieve this via a wet chemical process. They were then calcined at 800 °C for 4 h. The calcined powders' XRD examination indicates that the tetragonal phase rapidly diminishes with dopant concentration and concurrently gives way to rhombohedral phase. With an increase in dopant concentration, a SEM analysis of sintered discs showed a considerable change in grain size initially at the Zr site. Detailed investigations of the PZT's piezoelectric properties Significant changes in the piezoelectric charge coefficient, electromechanical coupling coefficient, resonant frequency, and mechanical quality factor can be seen in the samples that were created and examined. Analysis of Variance was used to evaluate the impact of additives on resonance frequency, and the results revealed that the addition of molybdenum and cobalt has a significant impact on resonance frequency.

Very-Low-Frequency Magnetoelectric Antennas for Portable Underwater Communication: Theory and Experiment

Finding an efficient way for underwater communication with a portable antenna at very low frequency (VLF 3–30 kHz) is challenging since the conventional electrical antennas require the size to be larger than 1/10 of the wavelength. Recently, acoustically driven antennas were proposed to realize portable VLF communication in air but lack the demonstration in a lossy environment. Here, we reported the first VLF underwater communication system based on a pair of acoustically actuated magnetoelectric (ME) antennas with small size of 10 cm in length. A theoretical analysis of reflection and radiation performance of the ME antenna was conducted, where the electromechanical resonance (EMR) frequency and effective magnetic dipole moment were estimated, and a near-field coupling model of a pair of ME antennas was further established. The results of theoretical predictions and finite element model (FEM) simulations were then compared with experimental measurements and their differences were discussed. A prototype of underwater communication system based on the ME antenna pair was finally presented, where a binary digital modulation with a bit rate of 100 b/s has been demonstrated, confirming the feasibility of ME antennas for portable underwater communication.

A self-biased, low-frequency, miniaturized magnetoelectric antenna for implantable medical device applications

Low-frequency (LF) magnetoelectric (ME) antennas are of great importance in implantable medical device (IMD) applications compared to their electromagnetic (EM) counterparts as they can potentially offer appropriate size miniaturization and lower path loss and higher efficiency. In this work, a self-biased, miniaturized LF ME antenna is proposed, which operates at its electromechanical resonant frequency of 49.9 kHz, with the size scaled down to only 1.75 mm3, which is significantly smaller than that of a comparable EM antenna. The proposed antenna that constitutes of a piezoelectric layer sandwiched between two magnetostrictive layers is characterized in both air and an optimized three-layered human tissue-mimicking phantom media to demonstrate the potential applications in deep-body communications. The near field radiation pattern of the ME antenna is measured experimentally. The maximum received power obtained at a distance of 1.2 m in air and phantom media is 20 and 8 nW, respectively. The proposed antenna has significantly lower path loss of 0.57 dB/m as compared to its higher frequency counterparts. Due to the lower path loss and smaller size, the proposed ME antenna can be suitable in several miniaturized IMD applications.

Influence of the conductivity of the magnetoelectric composites electrode under resonance frequency and its validation by laser vibrometer system

Magnetic sensor based on functional dielectric with high-efficiency energy property is projected to stimulate technological advancement in the fields of energy internet, power engineering materials, energy harvesting and storage, touchless human–machine interface, and magnetoreception for artificial intelligence (AI). At present, the research and development of hypersensitive magnetic sensors remain extraordinarily challenging. The effects of magnetoelectric (ME) composite electrodes with different conductivities and their electromechanical resonance frequency of Metal/PZT/Metal laminates were investigated in this paper. The results of calculations and experiments showed that the magnetoelectric coupling in the magnetoelectric composite (Metal/PZT/Metal) was mostly caused by the piezoelectricity effect in the radial direction and Ampere force under DC bias magnetic fields. According to the radial strain measurement, it can be further indicated that the capping layer with high conductivity produced a larger magnetoelectric voltage at the range of resonance frequency. Therefore, the ME voltage coefficient of the silver electrodes was higher than that of the gold electrodes, and they were 77.8 mV/(cm Oe) and 58.3 mV/(cm Oe) at a DC magnetic field of 3000 Oe, respectively. The ME coupling in the ME composite was mostly connected to the piezoelectricity effect and Ampere force, as well as the conductivity of the electrode layer of the ME composite. The optimization of the electrode structures of magnetoelectric composites provides a vital reference for the development of energy storage, information storage and sensing technology in new power 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.

Low-Frequency Magnetic Field Detection Using Magnetoelectric Sensor With Optimized Metglas Layers by Frequency Modulation

It is an important engineering challenge to detect a weak magnetic field <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${H}_{AC}$ </tex-math></inline-formula> at low frequencies (1-100 Hz) due to large noise. In this work, a magnetoelectric (ME) sensor using single-crystal quartz material as the piezoelectric phase and optimized magnetostrictive layers has been presented to sense the low-frequency magnetic field signals. Firstly, the ME response properties of the bulk Metglas/quartz/Metglas laminate sensor were studied and a high ME coefficient of 3038 V/(cm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\cdot $ </tex-math></inline-formula> Oe) has been attained in its electromechanical resonance frequency. With frequency modulation technique, which a magnetic low-frequency signal can be transferred to around resonance frequency of the sensor, the proposed sensor was used to detect the low frequency magnetic field signals under zero bias conditions. It is experimentally found that the absolute resolution with respect to a 1 Hz magnetic field can be decreased as low as 44 pT ± 1.41 pT with 20 layers of Metglas. More importantly, the ME coefficients with different layers under zero bias and the effect of Metglas layers on the limit of the detection at 1 Hz also have been investigated. The results show that the limit of the detection at 1 Hz can be decreased to 10 pT ± 0.32 pT with 14 layers of Metglas which indicates an enhancement by 4.4 times in comparison with 20 layers. This simple bulk Metglas/quartz/Metglas laminate sensor with optimized layers has a great potential to be used for low-frequency bio-magnetic signals measurement at room temperature.

Finite element simulation and characterization of one-port heterostructured surface acoustic wave resonator

The research work presents the study of a heterostructured surface acoustic wave (SAW) resonator consisting of an interdigital transducer (IDT), lithium niobate (LN), and silicon (Si) substrate. In the proposed structure, Silicon is the base substrate, above it layer of LN is placed then IDT is designed on it. The presented analysis includes the variation of the quality factor and electromechanical coupling coefficient with the change in the width of the piezoelectric layer. The electromechanical coupling coefficient (K 2), quality factor (Q-factor), velocity, resonance, admittance, and anti-resonance frequency have been studied for the thickness of the different layers of LN film. The higher quality factor of one port SAW devices reduces the energy loss and the K 2 of the devices indicates faster energy conversion. The Q-factor and K 2 are found to be depending on the thickness of LN, resonance, and anti-resonance frequency.

Electromechanical energy absorption, resonance frequency, and low-velocity impact analysis of the piezoelectric doubly curved system

In this research, electrically performance, vibration/resonance characteristics, low-velocity impact, and absorbed energy of the piezoelectric doubly curved panel on the viscoelastic substrate is carried out. For modeling the contact force between the structure and impactor, Hertz contact theory is presented. Hamilton’s principle and first-order shear deformation theory (FSDT) are presented for obtaining the governing and boundary condition equations of the structure under the low-velocity impact. Galerkin and Newmark solution procedures are presented for solving the governing equation in displacement, and time domains, respectively. This study's novelty is considering the effect of low-velocity impact on the electromechanical energy-absorption capability and resonance frequency of the piezoelectric doubly curved panel on the viscoelastic substrate. The results section is divided into three sections. The first one studied the impact of applied voltage and elastic parameter of foundation on the displacement field and absorbed energy of the structure during the time domain. The second one presents the influence of circumferential wave number, the thickness of the structure, and applied voltage on the current model's free and forced vibration characteristics under the low-velocity impact. In the third one, the influence of the elastic factor parameter of piezoelectric (c11/c12) and the velocity of the impactor on the indentation, contact force, absorbed energy in the panel, and indenter velocity are investigated in details. The golden result is that the curvature ratio (R1/a) of the doubly curved panel should be more than 3.8 because for R1/a less than 3.8, the structure encounters instability in response. As a desirable result for the designer, as the impactor velocity increases, the electrical panel's absorbed energy improves, and the maximum absorbed energy happens at the lower time of the impact process.

Normalized Modeling of Piezoelectric Energy Harvester Based on Equivalence Transformation and Unit-Less Parameters

Micro-electromechanical systems are ubiquitous in several energy harvesting solutions and can be used in applications such as bio-implantable devices and wireless micro-sensors. Piezoelectricity is an interesting key to perform the interface between environmental extracted energy and the power delivered to the load due to the use of mechanical vibration and resonance features. However, it is necessary for a detailed analysis in order to obtain an accurate understanding of the system. In this regard, some works deal with the normalization procedures to analyze the piezoelectric component behavior based on the mechanical resonance frequency. In order to enhance the system modeling, the electromechanical resonance frequency must also be analyzed. This paper deals with an approach to model the piezoelectric component that allows analyzing several unitless parameters that are critical to improve the performance of the system. In addition, a state-space model for the piezo-harvester based on the Class-E resonant rectifier is presented. Some experimental results are shown to validate the theoretical approach. [2019-0082]

A Low Frequency Mechanical Transmitter Based on Magnetoelectric Heterostructures Operated at Their Resonance Frequency.

Magneto-elasto-electric (ME) coupling heterostructures, consisting of piezoelectric layers bonded to magnetostrictive ones, provide for a new class of electromagnetic emitter materials on which a portable (area ~ 16 cm2) very low frequency (VLF) transmitter technology could be developed. The proposed ME transmitter functions as follows: (a) a piezoelectric layer is first driven by alternating current AC electric voltage at its electromechanical resonance (EMR) frequency, (b) subsequently, this EMR excites the magnetostrictive layers, giving rise to magnetization change, (c) in turn, the magnetization oscillations result in oscillating magnetic fields. By Maxwell’s equations, a corresponding electric field, is also generated, leading to electromagnetic field propagation. Our hybrid piezoelectric-magnetostrictive transformer can take an input electric voltage that may include modulation-signal over a carrier frequency and transmit via oscillating magnetic field or flux change. The prototype measurements reveal a magnetic dipole like near field, demonstrating its transmission capabilities. Furthermore, the developed prototype showed a 104 times higher efficiency over a small-circular loop of the same area, exhibiting its superiority over the class of traditional small antennas.

Magnetopiezofiber

The results of the magnetoelectric effect study in the magnetopiezofiber are presented. Magnetopiezofiber consists of mechanically coupled piezoelectric (one layer of lead zirconate titanate) and magnetostrictive (two metglass layers) fibers. The layers were joined together by epoxy under pressure and heating. The sample active area dimensions were 28x7x0,34 mm. The study of the magnetoelectric effect was carried out in the frequency range from 0 to 150 kHz and external magnetic field range from 0 to 100 Oe. Maximum value of the ME voltage coefficient αE = 62,75 V/cm-Oe was measured on the electromechanical resonance frequency f = 61 kHz with an external magnetic field of 4,5 Oe. Obtained results indicate the prospects of the proposed design in magnetoelectric devices application.

High-Pressure Helium Plasma Produced in the Local Electric Fields of a Piezoelectric Transformer

A millimeter-scale confined helium plasma was produced at 177 kPa by placing a piezoelectric transformer (PT) in the vicinity of the quartz tube and stimulating the transformer into an electromechanical resonance. The resulting plasma occurred at twice the electromechanical resonance frequency of the transformer. Time-resolved high-speed measurements of luminous emissions and simultaneous measurements of the proximity electric fields near the PT were used to demonstrate a strongly biperiodic behavior. Optical emission spectra, recorded using a synchronized spectrograph, were too weak to elucidate any tendencies toward a biperiodic spectral emission characteristic; however, time-integrated spectra over a broad range of wavelengths demonstrated the characteristic lines of nitrogen. The band of nitrogen emission lines associated with the 377-nm band head was used in conjunction with a spectrum-fitting routine to determine that the ions were essentially cold (rotation temperature on the order of 28 meV).

Highly efficient power conversion in magnetoelectric gyrators with high quality factor.

A high-Q magnetoelectric (ME) gyrator consisting of a trilayer laminate of nickel-iron-based constant elasticity alloy (Ni-Fe-Cr) and lead zirconate titanate with a coil wound around it has been developed and systematically characterized. Highly efficient magneto-mechanical-electric conversion can be achieved by means of the combination contributions of high quality factors from individuals, and much energy can be transferred through the gyration device. Under an electromechanical resonance frequency of 54.04 kHz, experimental results show that maximum efficiency reaches as high as 88.5% under an extremely low input density of 3.31 µW/cm3 with an optimum load resistance of 9.6 kΩ and a magnetic bias of 66 Oe. Such a highly efficient ME gyrator with a high Q factor can be beneficial or degrade the design goals that are likely to be achievable for practical applications in compact power transfer electronic devices.

Lorentz magneto-resonator model and colossal magnetodielectric effect of magnetoelectric heterostructures

In the vicinity of their resonance frequency, magnetoelectric heterostructures, which are laminated magnetostrictive material with a piezoelectric resonator, are highly sensitive to external magnetic field. At room temperature colossal magnetodielectric effect near to 30,000% close to the electromechanical resonance frequency was obtained in a magnetic field of about 400Oe. In this article we present a theoretical model for the magnetoelectric heterostructures based on the Lorentz magneto-resonator model. We show that the colossal magnetodielectric effect is related to the polarization direction of the piezoelectric resonator. When the direction of polarization is parallel to the direction of magnetostriction, the magnetodielectric effect of magnetoelectric heterostructures is much higher than that of the polarization direction perpendicular to the magnetostriction direction. The results of this model are in excellent agreement with experimental data. This modeling environment is found to be extremely useful for understanding how magnetoelectric heterostructures are working in various applications and how to design new magnetic-electric integrated resonant devices.

Structure, Ferroelectric, and Magnetoelectric Properties of Bulk PZT–NiFe1.9Co0.02О4 – δ Composites

The phase composition, microstructure, and dielectric, ferroelectric, magnetic, and magnetoelectric properties of bulk ceramic (1 – x)PZT–xNiFe1.9Co0.02О4 – δ composites with 3–0 connectivity have been studied. Using X-ray diffraction and electron microscopy, it has been established that the ferrimagnetic (spinel- like) and ferroelectric (tetragonal perovskite-like) phases separately exist in the composites of all compositions. The simultaneous existence of ferroelectric and ferrimagnetic properties in the composites is confirmed by measuring their P(E) and σ(B) hysteresis loops and studying the temperature dependences of dielectric and magnetic properties. The synthesized composites have high magnetoelectric characteristics: their voltage coefficient at x = 0.4 is 215 mV/A at a frequency of 1 kHz and 130 V/A at an electromechanical resonance frequency of 380 kHz.

Studies on magnetoelectric coupling in lead-free [(0.5) BCT-(0.5) BZT]-NiFe2O4 laminated composites at low and EMR frequencies

The possibility of achieving significantly higher magnetoelectric (ME) coupling in lead-free [(0.5)BCT-(0.5)BZT]/NiFe2O4 and NiFe2O4/[(0.5)BCT-(0.5)BZT]/NiFe2O4 laminates, processed by epoxy bonding using 1 mm -thick [(0.5)BCT-(0.5)BZT] and NiFe2O4 layers was reported. The effect of coupling modes in these bi- and tri-layer laminates was investigated through evaluating transverse (αE,31) and longitudinal (αE,33) ME coefficients both at low (1 kHz) and at electromechanical resonance frequencies (300–380 kHz) under external bias field. Measurements on frequency dependence of ME coefficients revealed resonance enhancement due to bending and radial acoustic modes. A maximum ME response of 0.98 and 1.1 V/cm⋅Oe was obtained for the [(0.5)BCT-(0.5)BZT]/NiFe2O4 and NiFe2O4/[(0.5)BCT-(0.5)BZT]/NiFe2O4 composites, respectively at the radial mode resonance, and these finding are explained on the basis of mechanical coupling exists at the interfaces of [(0.5)BCT-(0.5)BZT] and NiFe2O4 phases.