Converse Piezoelectric Effect Research Articles

Flexible Piezoelectric Nanocolumnar Composite Films as Flat-Panel Loudspeakers: Application and Modeling.

Highly anisotropic piezoelectric composites promise to progress electroacoustic devices as a class by combining the advantages of both piezoceramics and polymers. Fundamentally, piezoelectric loudspeakers employ the converse piezoelectric effect to convert electrical to mechanical energy. Quasi-1-3 piezoceramic/polymer composites enable flat-panel loudspeakers that are tunable in elastic modulus, with opportunities for mechanical flexibility, optical transparency, and large-area coverage. Their processing route enables relatively flexible design parameters, such as the particle loading, polymer-matrix modulus, film thickness, film size, and electrode-material stiffness. Alternative processing routes of electric field (E-field) aligned-piezoelectric composites are demonstrated, including using the relaxor ferroelectric lead magnesium niobate-lead titanate (PMN-PT) to enhance the acoustic performance and photocurable resins to accelerate the materials processing. Material properties critical for dielectrophoresis are characterized, and loudspeakers were fabricated based on the optimal processing conditions. Subsequently, electroacoustic characterization explores the effect of loudspeaker size, substrate stiffness, the microphone distance, the piezoceramic material, and the matrix modulus. Finally, finite-element (FE) modeling of the electromechanical behavior validates the natural frequencies and modes shapes of the loudspeakers via the analytical solution and frequency response to electrical and mechanical excitation. Good correspondence between the predicted electroacoustic performance and experimentally validated model is observed.

Submillisecond Electric Field Sensing with an Individual Rare-Earth Doped Ferroelectric Nanocrystal.

Understanding the dynamics of electrical signals within neuronal assemblies is crucial to unraveling complex brain functions. Despite recent advances in employing optically active nanostructures in transmembrane potential sensing, there remains room for improvement in terms of response time and sensitivity. Here, we report the development of such a nanosensor capable of detecting electric fields with a submillisecond response time at the single-particle level. We achieve this by using ferroelectric nanocrystals doped with rare-earth ions that produce upconversion (UC). When such a nanocrystal experiences a variation of surrounding electric potential, its surface charge density changes, inducing electric polarization modifications that vary, via a converse piezoelectric effect, the crystal field around the ions. The latter variation is finally converted into UC spectral changes, enabling optical detection of the electric potential. To develop such a sensor, we synthesized erbium and ytterbium-doped barium titanate crystals of ≈160 nm in size. We observed distinct changes in the UC spectrum when individual nanocrystals were subjected to an external field via a conductive atomic force microscope tip, with a response time of 100 μs. Furthermore, our sensor exhibits a remarkable sensitivity of 4.8 kV/cm/, enabling time-resolved detection of a fast-changing electric field of amplitude comparable to that generated during a neuron action potential.

Tactile Sensing and Rendering Patch with Dynamic and Static Sensing and Haptic Feedback for Immersive Communication.

Wearable human-machine interface (HMI) with bidirectional and multimodal tactile information exchange is of paramount importance in teleoperation by providing more intuitive data interpretation and delivery of tactilely related signals. However, the current sensing and feedback devices still lack enough integration and modalities. Here, we present a Tactile Sensing and Rendering Patch (TSRP) that is made of a customized expandable array which consists of a piezoelectric sensing and feedback unit fused with an elastomeric triboelectric multidimensional sensor and its inner pneumatic feedback structure. The primary functional unit of TSRP is mainly featured with a soft silicone substrate with compact multilayer structure integrating static and dynamic multidimensional tactile sensing capabilities, which synergistically leverage both triboelectric and piezoelectric effects. Additionally, based on the air chamber created by the triboelectric sensor and the converse piezoelectric effect, it provides pneumatic and vibrational haptic feedback simultaneously for both static and dynamic perception regeneration. With the aid of the other variants of this unit, the array shaped TSRP is capable of simulating different terrains, geometries, sliding, collisions, and other critical interactive events during teleoperation via skin perception. Moreover, immediate manipulation can be done on TSRP through the tactile sensors. The preliminary demonstration of TSRP interface with a completed control module in robotic teleoperation is provided, which shows the feasibility of assisting certain tasks in a complex environment by direct tactile communication. The proposed device offers a potential method of enabling bidirectional tactile communication with enriched key information for improving interaction efficiency in the fields of robot teleoperation and training.

Multicaloric response tuned by electric field in cylindrical MnAs/PZT magnetoelectric composite

The possibility observation of the electric field controlled multicaloric response through quasi-isostatic compression as a result of the converse piezoelectric effect was demonstrated on the cylindrical type magnetoelectric composite MnAs/PZT. It was shown that an electric voltage of 100 V corresponding to an electric field of E ∼0.3 kV/mm applied to the walls of the piezoelectric component PZT of the MnAs/PZT composite contributes to an increase in the maximum adiabatic temperature change by 0.2 K in the temperature range of the magnetostructural phase transition of MnAs ∼317 K at a magnetic field change of 1.8 T. Numerical analysis using the finite element method has shown that an electric field voltage of 100 V is capable of creating a quasi-isostatic mechanical stress in the region inside a cylindrical PZT tube of ∼3 MPa. Moreover, in the region of weak pressures up to 10 MPa, the contribution to the total adiabatic temperature change from piezo-mechanical compression linearly depends on the electrical voltage that can be used for control by magnetic and caloric properties of multicaloric materials.

Exploration of near room temperature magnetoelectric coupling in BaFe10Sc[formula omitted]O19:KNbO[formula omitted] composite

The consequential experimental endeavour has been undertaken to investigate and control the strain-mediated coupling of the magnetic and electric properties of the composite systems composed of Sc-doped BaFe12O19 and KNbO3. A distinct non-disperse ferroelectric-like anomaly is observed Tkink∼ 265 K, which concomitantly coincides with the magnetic Tcone transition. The observation of external magnetic field dependence dielectric response shows a noticeable decrease in permittivity values, indicating a negative magnetodielectric response. The maximum intrinsic magnetodielectric response is seen in the vicinity of room temperature with the magnetodielectric ratio of 5.4% @ 1 kHz. The linearity of −Δɛ′(H)% vs. M2 plot is phenomenologically described with the Ginzburg–Landau theory with the magnetoelectric coupling term γP2M2. The magnetoelectric coupling relies on strain to induce crystal deformations (flexomagnetoelectric response) on either the ferroelectric phase through magnetostriction or in the magnetic phase through the converse piezoelectric effect. Strain-induced changes in the magnetic as well as dielectric properties of the composites lead to strong magnetoelectric coupling to throw more light exploring a potential candidate for room-temperature multiferroic materials.

A wafer-level characterization method of thin film transverse piezoelectric coefficient evaluation

Accurate measurement of the piezoelectric property of thin films is critical for thin film process development and device design optimization. In this paper, we proposed a wafer-level thin film characterization method that provides a non-destructive, single-side measurement solution for evaluating and in-process monitoring the transverse piezoelectric coefficient (e31,f). The e31,f of piezoelectric films was determined by measuring the deflection of circular electrode induced by the converse piezoelectric effect, with the electrodes fabricated on top of piezoelectric thin film on a silicon substrate. The constitutive equation of the unimorph plate reveals a quadratic dependence of top electrode deflection (δ) on the radius (r), which was subsequently utilized to calculate the e31,f while considering the electrode edge effect. Determined by non-constant variations of |δ/r2| from finite element method (FEM) simulation results, the electrode edge effect leads to the specification of electrode size and substrate thickness for evaluating piezoelectric coefficient. A comprehensive FEM simulation analysis of the influence of wafer size and electrode location on the accuracy of the proposed method demonstrated its reliability for wafer-level characterization. The e31,f measurement results of single-crystal (s-PZT) and polycrystalline PZT (p-PZT) exhibit good agreement between the proposed wafer-level method and the die-level cantilever method. These results demonstrated that the proposed single-side wafer-level method provides a reliable measurement technique for e31,f characterization of piezoelectric thin film.

Optimized strain property in Sm3+ doped 0.67BiFeO3-0.33BaTiO3 ceramics by electric field induced lattice distortion and domain wall motion

BiFeO3-BaTiO3 based ceramics with good piezoelectric properties and high Curie temperature are potential candidates for high temperature piezoelectric actuators. In this study, a high strain value of about 0.376 % and the low strain hysteresis of 13.3 % achieved in 0.67Bi1-xSmxFeO3-0.33BaTiO3 (0.1 ≤ x ≤ 2.0) ceramics. The contribution from the E-induced nanodomains and/or PNRs wall motion by fine-tuning Sm3+ contributes the increased strain; The contribution from the converse piezoelectric effect and the electrostrictive effect enhanced with the increase of x, due to the enlarged lattice shrinkage by replacing Sm3+ with small ionic radius and subsequent lattice distortion under high electric field. The strategy to simultaneously enhance the E-induced lattice distortion and nanodomains and/or PNRs wall motion of strain and balance their fractions to reduce the strain hysteresis may provide new insights to meet the practical applications of high-precision displacement actuators.

Facile Coordination Transitions in AgCrX2 (X = S, Se): Unprecedented Electrostrain, Negative Piezoelectricity and Thermal Expansion.

The coefficients of piezoelectricity and thermal expansion are generally positive due to the bond anharmonicity. For converse piezoelectricity, the electrostrain obtained in prevalent ceramics is only around 1%. Here we propose that the coordination transition of metal cations may make a paradigm shift. Through first-principles calculations, we predict a series of low-energy phases with distinct coordinations for Ag ions in superionic conductor AgCrX2 (X = S, Se), including ferroelectric and nonpolar phases with distinct interlayer distances. The mobile feature of Ag ions, which can be attributed to its complex coordination chemistry, can facilitate transformation between various coordination phases. Such facile transitions with ultralow barriers can be driven by applying either pressure, an electric field, or a change in temperature, giving rise to various exotic effects, including electrostrain, negative piezoelectricity, and negative thermal expansion. All with unprecedented giant constants, those mechanisms stem from the coordination transitions, distinct from the weak linear effects in previous reports.

Electrically Controlled High Sensitivity Strain Modulation in MoS2 Field-Effect Transistors via a Piezoelectric Thin Film on Silicon Substrates.

Strain can modulate bandgap and carrier mobilities in two-dimensional (2D) materials. Conventional strain-application methodologies relying on flexible/patterned/nanoindented substrates are limited by low thermal tolerance, poor tunability, and/or scalability. Here, we leverage the converse piezoelectric effect to electrically generate and control strain transfer from a piezoelectric thin film to electromechanically coupled 2D MoS2. Electrical bias polarity change across the piezo film tunes the nature of strain transferred to MoS2 from compressive (∼0.23%) to tensile (∼0.14%) as verified through Raman and photoluminescence spectroscopies and substantiated by density functional theory calculations. The device architecture, on silicon substrate, integrates an MoS2 field-effect transistor on a metal-piezoelectric-metal stack enabling strain modulation of transistor drain current (130×), on/off ratio (150×), and mobility (1.19×) with high precision, reversibility, and resolution. Large, tunable tensile (1056) and compressive (-1498) strain gauge factors, electrical strain modulation, and high thermal tolerance promise facile integration with silicon-based CMOS and micro-electromechanical systems.

Intermediate multidomain state in single-crystalline Mn-doped BiFeO3 thin films during ferroelectric polarization switching

A intermediate multidomain state and large crystallographic tilting of 1.78° for the (hh0)pc planes of a (001)pc-oriented single-domain Mn-doped BiFeO3 (BFMO) thin film were found when an electric field was applied along the [110]pc direction. The anomalous crystallographic tilting was caused by ferroelastic domain switching of the 109° domain switching. In addition, ferroelastic domain switching occurred via an intermediate multidomain state. To investigate these switching dynamics under an electric field, we used in situ fluorescent X-ray induced Kossel line pattern measurements with synchrotron radiation. In addition, in situ inverse X-ray fluorescence holography (XFH) experiments revealed that atomic displacement occurred under an applied electric field. We attributed the atomic displacement to crystallographic tilting induced by a converse piezoelectric effect. Our findings provide important insights for the design of piezoelectric and ferroelectric materials and devices.

Challenges and opportunities in piezoelectric polymers: Effect of oriented amorphous fraction in ferroelectric semicrystalline polymers

AbstractDespite extensive research on piezoelectric polymers since the discovery of piezoelectric poly(vinylidene fluoride) (PVDF) in 1969, the fundamental physics of polymer piezoelectricity has remained elusive. Based on the classic principle of piezoelectricity, polymer piezoelectricity should originate from the polar crystalline phase. Surprisingly, the crystal contribution to the piezoelectric strain coefficient d31 is determined to be less than 10%, primarily owing to the difficulty in changing the molecular bond lengths and bond angles. Instead, >85% contribution is from Poisson's ratio, which is closely related to the oriented amorphous fraction (OAF) in uniaxially stretched films of semicrystalline ferroelectric (FE) polymers. In this perspective, the semicrystalline structure–piezoelectric property relationship is revealed using PVDF‐based FE polymers as a model system. In melt‐processed FE polymers, the OAF is often present and links the crystalline lamellae to the isotropic amorphous fraction. Molecular dynamics simulations demonstrate that the electrostrictive conformation transformation of the OAF chains induces a polarization change upon the application of either a stress (the direct piezoelectric effect) or an electric field (the converse piezoelectric effect). Meanwhile, relaxor‐like secondary crystals in OAF (SCOAF), which are favored to grow in the extended‐chain crystal (ECC) structure, can further enhance the piezoelectricity. However, the ECC structure is difficult to achieve in PVDF homopolymers without high‐pressure crystallization. We have discovered that high‐power ultrasonication can effectively induce SCOAF in PVDF homopolymers to improve its piezoelectric performance. Finally, we envision that the electrostrictive OAF mechanism should also be applicable for other FE polymers such as odd‐numbered nylons and piezoelectric biopolymers.

Direct and converse piezoelectricity of thickness tuned BCZT ceramics: toward efficient bilayered magnetoelectric devices

Here we report the effect of thickness reduction of bulk 0.5(Ba0.7Ca0.3)TiO3-0.5Ba(Ti0.8Zr0.2)O3 (BCZT) pellet on its direct and indirect piezoelectric properties. Upon reducing the thickness to 0.3 mm, the pellet shows a very high electrostrain of ∼0.7% and piezoelectric coefficient of ∼353 pC/N which were ∼0.14% and 258 pC/N for the 1 mm thick sample. These results have been correlated with the reduction in hardness and mutual mechanical clamping between the grains due to the reduced thickness of BCZT. Due to this improved strain sensitivity, the bilayered magnetoelectric (ME) devices of BCZT with magnetostrictive CoFe1.9Bi0.1O4 (CFBO) pellet have also shown gradually improved ME coupling coefficient ( αME ) with reduced BCZT thickness ( αME = 27 and 66 mV·cm−1·Oe−1 for 1 and 0.3 mm BCZT thickness, respectively). This demonstrates the possible applicability of thickness tuned BCZT pellets for various technological purposes.

Controllable and reversible electric field tuning of photoluminescence response in lanthanide ions doped ferroelectric films

The rare-earth doped ferroelectric photoluminescence (PL) phosphors are attracting considerable interest because of their flexible structure, wide band gap and high-quality fluorescence signal emission. Although the change of PL performance in different samples have been solved to a certain extent, how to achieve the tuning of PL intensity in one sample sensitively and reversibly is still an issue. In this work, we present an "electric-elastic-optical" coupled structure of 0.94Bi0.5Na0.5TiO3–0.06BaTiO3:1 mol%Eu3+ (BNTBT:Eu)/ 0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 (PMN-PT) heterostructures, which transfers strain from the PMN-PT to the BNTBT:Eu film via the converse piezoelectric effect and dynamically modulates the PL response of the epitaxial thin film. Our findings demonstrate that the PL response of the thin film can be effectively and linearly tuned under the influence of an external electric field. The relative change in the PL intensity (ΔI/I) of the BNTBT:Eu film was found to be linearly correlated with the lateral strain of the substrate. We also propose a novel design strategy for detecting strain, with significant implications for using BNTBT:Eu/PMN-PT heterostructures as sensors for integrating piezophotonic devices. This work provides valuable insights into the feasibility of electric field tuning of PL performance, which could inspire future research endeavors in the fields of nanophotonics, optical storage technology and photovoltaics.

Linear electro-optic effect in strontium barium niobate: A first principles study

We report a first-principles study of the linear electro-optic or Pockels effect in SrxBa1-xNb2O6 (SBN). SBN is an attractive material for building electro-optic modulators in silicon photonics as it has one of the highest known Pockels coefficients and can be integrated on Si. We investigate the microscopic mechanism behind the giant Pockels effect and find that the optical phonon contribution dominates the electro-optic response. We identify the phonon modes that have a significant contribution to the Pockels response and discuss the microscopic origin of the response. In addition, we analyze the contribution of the converse piezoelectric effect to the Pockels response. We find good agreement when comparing our results to available experiment.

Liquid Piezoelectric Materials: Linear Electromechanical Effect in Fluid Ferroelectric Nematic Liquid Crystals

AbstractThe first demonstration of converse piezoelectricity in 3D fluids is presented by measuring a linear electromechanical effect in ferroelectric nematic liquid crystals. The observed piezoelectric coupling constant below 6 kHz electric field is larger than 1 nC/N, comparable to, or better than, values for the strongest solid piezoelectric materials. Symmetry considerations indicate that the alignment of the ferroelectric nematic liquid crystal in the experimental study is not optimized, so the observed signal is likely only a fraction of the theoretically achievable signal. Understanding the electromechanical response of ferroelectric nematics will enable mechanical energy harvesting and open up a new avenue for developing fluid actuators, micro positioners, and electrically tunable optical lenses.

New [formula omitted]-type localization sets for [formula omitted]-eigenvalues of a piezoelectric-type tensor

The C-eigenvalues of piezoelectric-type tensors play an important role in piezoelectric effect and converse piezoelectric effect. By breaking N={1,2,…,n} into disjoint subsets S and S¯, He et al. (2021) provided an S-type inclusion set to locate all C-eigenvalues of a piezoelectric-type tensor. In this paper, we give two new S-type localization sets for C-eigenvalues of a piezoelectric-type tensor. Moreover, the theoretical comparisons of these localization sets are established. Finally, numerical experiments are performed to show the effectiveness of the main results.

NON-LINEAR MODEL OF A RECUPERATIVE SHOCK ABSORBER

This article examines the rationale for using a shock absorber with the function of recuperating mechanical energy into electrical energy. Current trends in the transport industry, regarding the need to use autonomous power sources in the transport infrastructure, are considered. This direction is promising due to the replacement of vehicles with internal combustion engines by electric transport, as well as the need for autonomous power supply of individual nodes and aggregates. The need for autonomy emerges acutely in the conditions of the energy crisis, and at the same time, the lack of energy resources. Special attention is paid to energy recovery using the direct and conversepiezoelectric effect. The structure, chemical and physical properties, principle of operation and practical application of piezoceramic transducers, and the possibility of their use as energy harvesters (generators) are considered. The considered scientific and technical problem, which consists in determining the nature of the negative impact of various types of external oscillations on the functioning of structural elements of vehicles, to reduce which various shock absorbers or dampers are used. This work considers the use of a recuperative shock absorber of vibration loads with the use of a piezoelectricenergy harvester as a converter of mechanical energy of vibrations into electrical energy. Piezoceramic inserts are used as an energy collector in the design of an automobile hydraulic shock absorber. An assessment of the efficiency of recuperation and conclusions regarding the feasibility of use and implementation are provided. The shock absorbers which are installed to absorb vibrations consume a large amount of mechanical energy, converting it into heat which is dissipated into the atmosphere. This energy, without reducing the efficiency of functioning, can be beneficially used by using a piezoelectric generator with piezoelectric ceramics to convert mechanical energy into electrical energy.

Compositional Modification of Epitaxial Pb(Zr,Ti)O3 Thin Films for High‐Performance Piezoelectric Energy Harvesters

AbstractIn this study, Piezoelectric energy harvesters (PEHs) are fabricated based on epitaxial Pb(Zr,Ti)O3 (PZT) thin films deposited by an RF magnetron sputtering with varied Zr/[Zr+Ti] ratio. For a compatibility with micro‐electromechanical systems, the epitaxial PZT thin films are deposited on Si substrates (PZT/Si). The morphotropic phase boundary (MPB) are formed in the compositional range of 0.44 ≤ Zr/[Zr+Ti] ≤ 0.51 of the epitaxial PZT/Si, which is far broader than that of the bulk PZT. Meanwhile, effective transverse piezoelectric coefficient (|e31,f|) values are evaluated by the direct and converse piezoelectric effects using the unimorph cantilever method. Among the compositions, the rhombohedral‐dominant MPB (MPB‐R) of Zr/[Zr+Ti] = 0.51 exhibits a direct |e31,f| of 10.1 C m−2 and a relative permittivity (εr) of 285, leading to the maximum figure of merit of 40 GPa in this study. On the other hand, the maximum converse |e31,f| of 14.0 C m−2 is measured from the tetragonal‐dominant MPB (MPB‐T) of Zr/[Zr+Ti] = 0.44. At a resonance frequency, the MPB‐T presents a high output power density of 301.5 µW−1/(cm2 g2) under an acceleration of 3 m−1 s−2, which is very promising for the high‐performance PEH applications.

A Biomimetic Piezoelectric Composite‐Driven Undulation Underwater Robotic Structure: Characteristic Analysis and Experimental Investigation

Numerous proposals and recommendations have been made in the development of underwater undulation robots, but very few studies have focused on the undulation characteristics of undulation robots. The undulating mode of the clearnose skate utilizing the activation of the pectoral fins in undulatory bursts is particularly suitable for slow and efficient swimming. Inspired by the working principle of the clearnose skate, herein, an undulation robotic structure is presented. Considering the hydrodynamic skeleton and propulsion mechanism of the clearnose skate, the solution is based on a piezoelectric composite for realizing undulatory propulsion. This approach leverages the converse piezoelectric effect and modal coupling to produce the desired undulating motion, thereby achieving the undulation design of the robot. The proposed robotic structure can realize the propulsion mode using piezoelectric composites to undulate in the same direction and can use the clockwise or counterclockwise undulation of piezoelectric composites to achieve the steering mode. In addition, finite element analysis is employed as an approach to investigate the undulation characteristics and transient vibration characteristics of the robot. The operational efficiency of the robotic structure is assessed through experiments. The results show that the propulsion mode achieves the speed of 3.33 body‐length s−1. The steering mode exhibits the steering velocities of 17.4 deg s−1.

Tunable dynamic microwave properties of a magnetic skyrmion manipulated by strains

In this paper, we theoretically studied the tunable dynamic microwave properties of a magnetic skyrmion manipulated by strains through micromagnetic simulations. The strains are induced by voltage due to the converse piezoelectric effect and then applied to modulate the dynamic characteristics through the magneto-elastic coupling effect. The tunable dynamic microwave characteristics of a breathing mode and gyration modes are investigated. The resonant frequency of the breathing mode increases abruptly and then decreases slowly with the strain changing from compressive to tensile. A clockwise gyrotropic mode has been obtained, and the resonant frequency keeps increasing with the strain changing from compressive to tensile. In particular, strains can induce different gyrotropic trajectories of the skyrmion driven by an in-plane microwave field. Our results may contribute to the understanding of dynamic properties of skyrmions manipulated by voltage-induced strains and provide a method to realize tunable spintronic microwave devices based on skyrmion.