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Showing papers on "Piezoelectricity published in 2006"


Journal ArticleDOI
14 Apr 2006-Science
TL;DR: This approach has the potential of converting mechanical, vibrational, and/or hydraulic energy into electricity for powering nanodevices.
Abstract: We have converted nanoscale mechanical energy into electrical energy by means of piezoelectric zinc oxide nanowire (NW) arrays. The aligned NWs are deflected with a conductive atomic force microscope tip in contact mode. The coupling of piezoelectric and semiconducting properties in zinc oxide creates a strain field and charge separation across the NW as a result of its bending. The rectifying characteristic of the Schottky barrier formed between the metal tip and the NW leads to electrical current generation. The efficiency of the NW-based piezoelectric power generator is estimated to be 17 to 30%. This approach has the potential of converting mechanical, vibrational, and/or hydraulic energy into electricity for powering nanodevices.

6,692 citations


Journal ArticleDOI
TL;DR: A piezoelectric field effect transistor (PE-FET) that is composed of a ZnO nanowire (NW) bridging across two Ohmic contacts, in which the source to drain current is controlled by the bending of the NW.
Abstract: Utilizing the coupled piezoelectric and semiconducting dual properties of ZnO, we demonstrate a piezoelectric field effect transistor (PE-FET) that is composed of a ZnO nanowire (NW) (or nanobelt) bridging across two Ohmic contacts, in which the source to drain current is controlled by the bending of the NW. A possible mechanism for the PE-FET is suggested to be associated with the carrier trapping effect and the creation of a charge depletion zone under elastic deformatioin. This PE-FET has been applied as a force/pressure sensor for measuring forces in the nanonewton range and even smaller with the use of smaller NWs. An almost linear relationship between the bending force and the conductance was found at small bending regions, demonstrating the principle of nanowire-based nanoforce and nanopressure sensors.

985 citations


Journal ArticleDOI
TL;DR: In this article, a lead-free piezoelectric ceramics, with the nominal composition of 0.948(K 0.5Na0.5)NbO3-0.052LiSbO 3 (KNN-LS5.2), were synthesized by conventional solid-state sintering, and the pieziolectric and electromechanical properties were characterized as a function of temperature, which mimicked the compositional variation seen in the proximity of a morphotropic phase boundary.
Abstract: Lead-free piezoelectric ceramics, with the nominal composition of 0.948(K0.5Na0.5)NbO3–0.052LiSbO3 (KNN-LS5.2), were synthesized by conventional solid-state sintering, and the piezoelectric and electromechanical properties were characterized as a function of temperature. The Curie temperature of the KNN based perovskite material was found to be 368°C with an orthorhombic-tetragonal polymorphic phase transition (TO-T) temperature at approximately ∼35°C. The room temperature dielectric permittivity (e33T∕e0) and loss were found to be 1380 and 2%, respectively, with piezoelectric properties of k33∼62% and d33∼265pC∕N and k31∼30% and d31∼−116pC∕N. The temperature dependence of the properties mimicked the compositional variation seen in the proximity of a morphotropic phase boundary [e.g., lead zirconate titanate (PZT)], with a maxima in the dielectric and piezoelectric properties and a corresponding “softening” of the elastic properties. Unlike that found for PZT-type materials, the modified KNN material exhi...

599 citations


Journal ArticleDOI
TL;DR: In this paper, highly dense Niobate ceramics were prepared using spark plasma sintering (SPS). Although the SPS temperature was as low as 920 C, the density of the Na 0.5 K 0.5 NbO 3 solid solution was raised to 4.47 g/cm 3 (>99% of the theoretical density).
Abstract: Lead-free piezoelectric ceramics have received attention because of increasing interest in environmental protection. Niobate ceramics such as NaNbO 3 and KNbO 3 have been studied as promising Pb-free piezoelectric ceramics, but their sintering densification is fairly difficult. In the present study, highly dense Na 0.5 K 0.5 NbO 3 ceramics were prepared using spark plasma sintering (SPS). Although the SPS temperature was as low as 920 C, the density of the Na 0.5 K 0.5 NbO 3 solid solution ceramics was raised to 4.47 g/cm 3 (>99% of the theoretical density). After post-annealing in air, reasonably good ferroelectric and piezoelectric properties were obtained in the Na 0.5 K 0.5 NbO 3 ceramics with submicron grains. The crystal phase of the Na 0.5 K 0.5 NbO 3 has an orthorhombic structure. The Curie temperature is 395°C and the piezoelectric parameter (d 33 ) of the Na 0.5 K 0.5 NbO 3 ceramics reached 148 pC/N.

422 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated the piezoelectric properties of a solid solution of the binary system, x(Bi 1/2Na1/2)TiO3 and x(1-x) Bi 1/ 2K1/ 2) TiO3 [BNKT100x; x=0.50 −0.98] focusing on depolarization temperature, Td.
Abstract: The piezoelectric properties of a solid solution of the binary system, x(Bi1/2Na1/2)TiO3–(1-x)(Bi1/2K1/2)TiO3 [BNKT100x; x=0.50–0.98] were investigated, focusing on depolarization temperature, Td. Fine piezoelectric properties in lead-free piezoelectric ceramics were obtained near the morphotropic phase boundary (MPB) composition between the rhombohedral and tetragonal structures, and the highest electromechanical coupling factor, k33, and piezoelectric constant, d33, were 0.56 for BNKT84 and 157 pC/N for BNKT80, respectively. However, the Td of BNKT80 was low (174 °C). The Td of the MPB composition was low, and the Td near the MPB composition was sharply decreased. It is thought that BNKT70 is a candidate composition for lead-free actuator applications owing to its relatively large piezoelectric constant, d33 (126 pC/N), dynamic d33 (214 pm/V), and high depolarization temperature, Td (206 °C). In this study, we determined depolarization temperature, Td, from the temperature dependence of dielectric and piezoelectric properties.

387 citations


Journal ArticleDOI
TL;DR: In this paper, a relatively large remanent polarization was produced, ranging from 16 μC/cm2 for pure Na0.5K 0.5NbO3 (NKN) piezoelectric ceramics to 23 µC/ cm2 for ZnO-added NKN samples.
Abstract: Lead-free Na0.5K0.5NbO3 (NKN) piezoelectric ceramics were fairly well densified at a relatively low temperature under atmospheric conditions. A relative density of 96%–99% can be achieved by either using high-energy attrition milling or adding 1 mol% oxide additives. It is suggested that ultra-fine starting powders by active milling or oxygen vacancies and even liquid phases from B-site oxide additives mainly lead to improved sintering. Not only were dielectric properties influenced by oxide additives, such as the Curie temperature (Tc) and dielectric loss (D), but also the ferroelectricity was modified. A relatively large remanent polarization was produced, ranging from 16 μC/cm2 for pure NKN to 23 μC/cm2 for ZnO-added NKN samples. The following dielectric and piezoelectric properties were obtained: relative permittivity ɛT33/ɛ0=570–650, planar mode electromechanical coupling factor, kp=32%–44%, and piezoelectric strain constant, d33=92–117 pC/N.

375 citations


Journal ArticleDOI
TL;DR: The experimental observation of piezoelectric generation from a single ZnO wire/belt is presented for illustrating a fundamental process of converting mechanical energy into electricity at nanoscale.
Abstract: This paper presents the experimental observation of piezoelectric generation from a single ZnO wire/belt for illustrating a fundamental process of converting mechanical energy into electricity at nanoscale. By deflecting a wire/belt using a conductive atomic force microscope tip in contact mode, the energy is first created by the deflection force and stored by piezoelectric potential, and later converts into piezoelectric energy. The mechanism of the generator is a result of coupled semiconducting and piezoelectric properties of ZnO. A piezoelectric effect is required to create electric potential of ionic charges from elastic deformation; semiconducting property is necessary to separate and maintain the charges and then release the potential via the rectifying behavior of the Schottky barrier at the metal-ZnO interface, which serves as a switch in the entire process. The good conductivity of ZnO is rather unique because it makes the current flow possible. This paper demonstrates a principle for harvesting energy from the environment. The technology has the potential of converting mechanical movement energy (such as body movement, muscle stretching, blood pressure), vibration energy (such as acoustic/ultrasonic wave), and hydraulic energy (such as flow of body fluid, blood flow, contraction of blood vessels) into electric energy that may be sufficient for self-powering nanodevices and nanosystems in applications such as in situ, real-time, and implantable biosensing, biomedical monitoring, and biodetection.

367 citations


Book
10 Aug 2006
TL;DR: In this paper, the Lagrangian dynamics of mechanical systems are studied and Lagrange's equations with constraints with respect to kinematic constraints for continuous systems are presented. But the authors focus on continuous systems and do not consider the case of discrete transducers.
Abstract: Lagrangian dynamics of mechanical systems 1.1 Introduction 1.2 Kinetic state functions 1.3 Generalized coordinates, kinematic constraints 1.4 The principle of virtual work 1.5 D'Alembert's principle 1.6 Hamilton's principle 1.7 Lagrange's equations 1.8 Lagrange's equations with constraints 1.9 Conservation laws 1.10 More on continuous systems 1.11 References 2 Dynamics of electrical networks 2.1 Introduction 2.2 Constitutive equations for circuit elements 2.3 Kirchhoff's laws 2.4 Hamilton's principle for electrical networks 2.5 Lagrange's equations 2.6 References 3 Electromechanical Systems 3.1 Introduction 3.2 Constitutive relations for transducers 3.3 Hamilton's Principle 3.4 Lagrange's equations 3.5 Examples 3.6 General electromechanical transducer 3.7 References 4 Piezoelectric Systems 4.1 Introduction 4.2 Piezoelectric transducer 4.3 Constitutive relations of a discrete transducer 4.4 Structure with a discrete piezoelectric transducer 4.5 Multiple transducer systems 4.6 General piezoelectric structure 4.7 Piezoelectric material 4.8 Hamilton's principle 4.9 Rosen's piezoelectric transformer 4. 10 References 5 Piezoelectric laminates 5.1 Piezoelectric beam actuator 5.2 Laminar sensor 5.3 Spatial modal filters 5.4 Active beam with collocated actuator-sensor 5.5 Piezoelectric laminates 5.6 References 6 Active and Passive Damping with Piezoelectric Transducers 6.1 Introduction 6.2 Active strut, open-loop FRF 6.3 Active damping via 1FF 6.4 Admittance of the piezoelectric transducer 6.5 Damping via resistive shunting 6.6 Inductive shunting 6.7 Decentralized control 6.8 General piezoelectric structure 6.9 Self-sensing 6.10 Other active damping strategies 6.11 Remark 6.12 References Bibliography Index

338 citations


Journal ArticleDOI
TL;DR: In this paper, a thin film lead zirconate titanate Pb(Zr,Ti)O3 (PZT), energy harvesting MEMS device is developed to enable self-supportive sensors for in-service integrity monitoring of large social and environmental infrastructures at remote locations.
Abstract: A thin film lead zirconate titanate Pb(Zr,Ti)O3 (PZT), energy harvesting MEMS device is developed to enable self-supportive sensors for in-service integrity monitoring of large social and environmental infrastructures at remote locations. It is designed to resonate at specific frequencies of an external vibrational energy source, thereby creating electrical energy via the piezoelectric effect. Our cantilever device has a PZT/SiNx bimorph structure with a proof mass added to the end. The Pt/Ti top electrode is patterned into an interdigitated shape on top of the sol-gel-spin coated PZT thin film in order to employ the d 33 mode. The base-shaking experiment at the first resonant frequency of the cantilever (170 × 260 μm) generates 1 μW of continuous electrical power to a 5.2 MΩ resistive load at 2.4 V DC. The effect of proof mass, beam shape and damping on the power generating performance are modeled to provide a design guideline for maximum power harvesting from environmentally available low frequency vibrations. A spiral cantilever is designed to achieve compactness, low resonant frequency and minimum damping coefficient, simultaneously.

322 citations


Journal ArticleDOI
TL;DR: In this article, the coupling between strain gradients and polarization, and conversely between strain and polarization gradients, is investigated in non-centrosymmetric dielectric systems.
Abstract: In a piezoelectric material, an applied uniform strain can induce an electric polarization (or vice versa). Crystallographic considerations restrict this technologically important property to noncentrosymmetric systems. It has been shown both mathematically and physically that a nonuniform strain can potentially break the inversion symmetry and induce polarization in nonpiezoelectric materials. The coupling between strain gradients and polarization, and conversely between strain and polarization gradients, is investigated in this work. While the conventional piezoelectric property is nonzero only for certain select materials, the nonlocal coupling of strain and electric field gradients is (in principle) nonzero for all dielectrics, albeit manifesting noticeably only at the nanoscale, around interfaces or in general in the vicinity of high field gradients. Based on a field theoretic framework accounting for this phenomena, we (i) develop the fundamental solutions (Green's functions) for the governing equations, and (ii) motivated by eventual applications for quantum dots, solve the general embedded mismatched inclusion problem with explicit results for the spherical and cylindrical shape. Expectedly, our results for the aforementioned problems are size dependent and indicate generation of high electric fields reaching values of approximately hundreds of kV/m in selected sizes and locations---even in isotropic centrosymmetric nonpiezoelectric materials.

311 citations


Book ChapterDOI
01 Jan 2006
TL;DR: In this paper, the hysteresis of piezoelectric ferroelectric materials is investigated in the context of the construction of a ferroelectric ferromagnetic circuit.
Abstract: Keywords: hysteresis ; ferroelectric ; piezoelectric Reference LC-CHAPTER-2006-001 Record created on 2006-08-03, modified on 2017-05-10

Journal ArticleDOI
TL;DR: In this paper, the fabrication and characterization of an electric field-tunable yttrium iron garnet (YIG)-lead zirconate titanate (PZT) microwave resonator is discussed.
Abstract: The fabrication and characterization of an electric field-tunable yttrium iron garnet (YIG)-lead zirconate titanate (PZT) microwave resonator are discussed. The device is based on ferromagnetic resonance for YIG. The tunability is accomplished through magnetoelectric interactions. For an electric field E=10kV∕cm across PZT, a frequency shift of 18–25MHz that was an order of magnitude higher the frequency width of the absorption profile for the resonator was measured. Upon reversal of the direction of E, the shift also reversed. The YIG-PZT bilayer structures could form the basis for rapid, electric field tunable, passive microwave resonators and filters.

Journal ArticleDOI
TL;DR: In this article, the piezoelectric and ferroelectric properties of [Bi0.5(Na1−x−yKxLiy) 0.5]TiO3 (BNKLT-x∕y) lead-free piezeloric ceramics were studied.
Abstract: The piezoelectric and ferroelectric properties of [Bi0.5(Na1−x−yKxLiy)0.5]TiO3 (BNKLT-x∕y) lead-free piezoelectric ceramics were studied. The ceramics show excellent piezoelectric and ferroelectric properties, and the optimum properties measured are as follows: piezoelectric constant d33=231pC∕N, planar and thickness electromechanical coupling factors kP=41.0% and kt=50.5%, remanent polarization Pr=40.2μC∕cm2, and coercive field Ec=2.47kV∕mm, respectively. Polarization versus electric (P-E) hysteresis loops of the ceramics are well rectangle shaped, and the dependence of P-E loops on temperature reveals that the depolarization temperature Td of BNKLT-0.15∕0.075 ceramics, which simultaneously have good piezoelectric properties (d33=164pC∕N,kp=36.3%,kt=48.6%) and strong ferroelectricity (Pr=38.8μC∕cm2,Ec=3.73kV∕mm) at room temperature, is about 195 °C.

Journal ArticleDOI
TL;DR: The piezoelectric effect was first observed in polyvinylidene fluoride polymer (PVDF) in 1969, and the pyroelectric effect was found several years later as mentioned in this paper.
Abstract: The piezoelectric effect was first observed in polyvinylidene fluoride polymer (PVDF) in 1969, and the pyroelectric effect was found several years later. A number of additional ferroelectric polymers have been discovered since that time including the copolymer PVDF with trifluoroethylene (P(VDF-TrFE)), and the odd-numbered nylons. A large number of applications of piezoelectricity and pyroelectricity have been developed. The magnitudes of the effects in polymers are much lower than those of ferroelectric ceramics (an exception is the piezoelectric effect in porous polymers). However, other factors make these very desirable materials for applications. The polymers have low permittivities, low acoustic impedances and low thermal conductivities. They are available in large area sheets, flexible, and relatively low in cost. Major applications include microphones and loudspeakers, ultrasonic devices, SAW transducers, actuators, single-element infrared detectors and many others. This review will describe some of the lesser-known applications of these materials in the areas of tactile devices, energy conversion, porous polymers, property measurement, pyroelectric infrared sensors, shock sensors and space science.

Journal ArticleDOI
TL;DR: In this article, single-phase multiferroic Bi1−xNdxFeO3 (x=0.15) ceramics are polarized and their piezoelectric and pyroelectric effects are reported.
Abstract: Single-phase multiferroic Bi1−xNdxFeO3 (x=0–0.15) ceramics are polarized and their piezoelectric and pyroelectric effects are reported. The success in polarizing the ceramics originates from low electrical conductivities controlled predominantly by the Poole-Frenkel conduction mechanism. Limited internal traps due to reduced oxygen vacancies in the ceramics result in sufficiently low leakage current densities of <30mA∕m2 even at a high electric field of 145kV∕cm. The piezoelectric d33 coefficients of the ceramics before and after annealing at 550°C for 4h are measured to be ∼28 and ∼24pC∕N, respectively. These values are higher than those of most major lead-free high-temperature piezoelectric ceramics.

Journal ArticleDOI
TL;DR: In this article, a method has been developed to control the pull-in voltage of the fixed-fixed and cantilever MEM actuators and measure the residual stress in the fixed fixed model using of the piezoelectric layers that have been located on the upper and lower surfaces of actuator.
Abstract: In this paper, a novel method has been developed to control the pull-in voltage of the fixed-fixed and cantilever MEM actuators and measure the residual stress in the fixed-fixed model using of the piezoelectric layers that have been located on the upper and lower surfaces of actuator. In the developed model, the tensile or compressive residual stresses, fringing-field and axial stress effects in the fixed-fixed end type micro-electro-mechanical systems actuator have been considered. The non-linear governing differential equations of the MEM actuators have been derived by considering the piezoelectric layers and mentioned effects. The results show that due to different applied voltage to the piezoelectric layers, the pull-in voltage can be controlled and in the fixed-fixed type the unknown value of the residual stress can be obtained.

Journal ArticleDOI
TL;DR: In this article, a relation on electric field dependent surface stress, or alternatively surface piezoelectricity, is proposed and based on such a relation, a piezolectric ring under prescribed potential has been studied.
Abstract: A relation on electric field dependent surface stress, or alternatively surface piezoelectricity, is proposed in this paper. Based on such relation, a piezoelectric ring under prescribed potential has been studied and the results show that the surface piezoelectricity may play an important role in the electromechanical behavior of piezoelectric nanostructures. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Journal ArticleDOI
TL;DR: The piezoelectric field turns out to be a rare example of a physical quantity for which the first-order and second-order contributions are of comparable magnitude.
Abstract: We show that the piezoelectric effect that describes the emergence of an electric field in response to a crystal deformation in III-V semiconductors such as GaAs and InAs has strong contributions from second-order effects that have been neglected so far. We calculate the second-order piezoelectric tensors using density-functional theory and obtain the piezoelectric field for $[111]$-oriented ${\mathrm{In}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x}\mathrm{As}$ quantum wells of realistic dimensions and concentration $x$. We find that the linear and the quadratic piezoelectric coefficients have the opposite effect on the field, and for large strains (large In concentration) the quadratic terms even dominate. Thus, the piezoelectric field turns out to be a rare example of a physical quantity for which the first-order and second-order contributions are of comparable magnitude.

Journal ArticleDOI
TL;DR: Experimental results demonstrate significant reduction in hysteresis due to the use of a charge amplifier, and piezoelectric shunt damping, a technique previously resident in the field of smart structures, is applied to damp tube vibration.
Abstract: Piezoelectric tube scanners are employed in high-resolution positioning applications such as scanning probe microscopy and nanofabrication. Much research has proceeded with the aim of reducing hysteresis and vibration-the two foremost problems associated with piezoelectric tube scanners. In this paper, two simple techniques are proposed for simultaneously reducing hysteresis and vibration: 1) A new dc accurate charge amplifier is shown to significantly reduce hysteresis while avoiding characteristic voltage drift. 2) Piezoelectric shunt damping, a technique previously resident in the field of smart structures, has been applied to damp tube vibration. By attaching an LCR impedance to a single tube electrode, the first mechanical mode is reduced in magnitude by more than 20 dB.

Journal ArticleDOI
TL;DR: In this paper, the piezoelectric coefficient d 33eff of aluminium nitride thin films was measured using both, piezoresponse force microscopy and an interferometric technique.
Abstract: The piezoelectric coefficient d 33eff of aluminium nitride thin films was measured using both, the piezoresponse force microscopy and an interferometric technique. Wurtzite AlN thin films were prepared on Si (1 1 1) substrates by reactive dc-sputtering and by metal organic chemical vapor deposition (MOCVD). Direct measurements of the inverse piezoelectric effect in the picometer range showed that the acceptable tolerance in the crystal orientation is much larger for MEMS applications than expected previously. The value of the effective piezoelectric coefficient d 33 for the prepared AlN thin films remained as high as 5.1 pm/V even for lower degrees of texture.

Journal ArticleDOI
TL;DR: It is shown that, for a given energy harvesting technique, generators using single crystals deliver 20 times more power than generators using piezoelectric ceramics.
Abstract: This paper compares the performances of vibration-powered electrical generators using a piezoelectric ceramic and a piezoelectric single crystal associated to several power conditioning circuits. A new approach of the piezoelectric power conversion based on a nonlinear voltage processing is presented, leading to three novel high performance power conditioning interfaces. Theoretical predictions and experimental results show that the nonlinear processing technique may increase the power harvested by a factor of 8 compared to standard techniques. Moreover, it is shown that, for a given energy harvesting technique, generators using single crystals deliver 20 times more power than generators using piezoelectric ceramics.

Book
20 Mar 2006
TL;DR: In this paper, three dimensional theories of piezoelectric plates are presented. But they do not consider nonlinear effects in Electroelastic Plates and Parallelepeds.
Abstract: Three-Dimensional Theories Piezoelectric Plates Laminated Plates and Plates on Substrates Nonlinear Effects in Electroelastic Plates Piezoelectric Shells Piezoelectric Beams Piezoelectric Rings Piezoelectric Parallelepipeds.

Journal ArticleDOI
TL;DR: In this paper, a measurement and analysis technique has been developed to quantify the complex contributions to the nonlinear dielectric and converse piezoelectric response in ferroelectric ceramics.
Abstract: A measurement and analysis technique has been developed to quantify the complex contributions to the nonlinear dielectric and converse piezoelectric response in ferroelectric ceramics. The electric field dependent response was quantified in two important bulk ceramic piezoelectric systems, Pb(Zr1−x,Tix)O3 and (1−x)BiScO3–xPbTiO3 (BS-PT), at low frequency and room temperature. The nonlinear response was shown to obey the Rayleigh law in the specific field and frequency ranges reported. Analysis of BS-PT perovskites with different crystal structures revealed a ferroelectric phase dependence on the magnitude of the nonlinear contribution to the dielectric and piezoelectric responses. The magnitudes of the nonlinear coefficients, which quantify the irreversible extrinsic response, were found to be smallest in the ferroelectric tetragonal phase, larger in the rhombohedral composition, and highest at the morphotropic phase boundary. Finally, this work provides strong evidence that the same loss mechanism domina...

Journal ArticleDOI
TL;DR: In this article, an enhanced semi-passive damping technique was proposed to enhance the electromechanical coupling by artificially increasing the voltage amplitude delivered by the piezoelectric patches.
Abstract: Semi-passive damping techniques have been developed recently to address the problem of structural damping. Contrary to the standard passive piezoelectric damping, these new techniques adapt to environmental variations. Moreover, they present interesting multimodal damping performances. However, their efficiency is strongly correlated with their electromechanical coupling. The enhanced semi-passive damping technique presented herein compensates for this drawback. It reinforces the electromechanical coupling by artificially increasing the voltage amplitude delivered by the piezoelectric patches. Theoretical predictions and experimental results show a −24 dB attenuation on the vibration of a resonant cantilever steel beam, while reducing the piezoelectric material volume by 83%.

Journal ArticleDOI
TL;DR: In this paper, the authors proposed a new approach to harvest electrical energy from a mechanically excited structure equipped with piezoelectric elements. But this method is not compatible with the standard approach.
Abstract: This article describes a new approach to harvest electrical energy from a mechanically excited structure equipped with piezoelectric elements. Standard harvesting circuits using piezoelectric elements as an electric generator consist of an AC-DC converter coupled to a load. The technique proposed herein is fully compatible with the standard approach. The difference consists in adding up an electrical switching device connected in parallel with the piezoelectric elements. The switch device is triggered on the maxima or minima of the displacement and realizes a voltage inversion through an inductor. This method allows the artificial increase of the piezoelements' output voltage, resulting in a significant increase of the electrical power flow. It is shown that the power flow transfer strongly depends on the structure electromechanical coupling coefficient. For a weakly coupled structure using this new technique, the electrical power can be increased by over 400%.

Journal ArticleDOI
TL;DR: In this paper, the authors reported direct measurements of non-180° domain wall motion in ceramic lead zirconate titanate during application of sub-coercive cyclic driving electric fields using an in situ stroboscopic neutron diffraction technique.
Abstract: The dynamic piezoelectric response of ferroelectric ceramics is comprised of both intrinsic (piezoelectric lattice strain) and extrinsic (non-180° domain wall motion) components. Here the authors report direct measurements of non-180° domain wall motion in ceramic lead zirconate titanate during application of subcoercive cyclic driving electric fields using an in situ stroboscopic neutron diffraction technique. During unipolar cycling at 1Hz and half of the coercive field, non-180° domain switching gives rise to approximately 34% of the measured d33 coefficient of 400pm∕V.

Journal ArticleDOI
TL;DR: In this paper, the nonlinear vibration and dynamic response of a functional graded material (FGM) plate with surface-bonded piezoelectric layers in thermal environments were investigated.

Journal ArticleDOI
TL;DR: In this article, a high energy density piezoelectric material with high voltage constant and strain constant was reported and the condition for obtaining large magnitude of g constant was derived to be as ∣d∣=en, where e is the permittivity of the material and n is constant having lower bound of 0.5.
Abstract: This letter reports a high energy density piezoelectric material in the system given as: Pb[(Zr0.52Ti0.48)O3]1−x[(Zn1∕3Nb2∕3)O3]x+yMnCO3, where x=0.1 and y varies from 0.5to0.9wt%. A piezoelectric material with high energy density is characterized by a high product of piezoelectric voltage constant (g) and piezoelectric strain constant (d). The condition for obtaining large magnitude of g constant was derived to be as ∣d∣=en, where e is the permittivity of the material and n is constant having lower bound of 0.5. It was found that for all practical polycrystalline piezoelectric ceramic materials the magnitude of n lies in the range of 1.1–1.30 and as the magnitude of n decreases towards unity a giant enhancement in the magnitude of g was obtained. A two step sintering process was developed to optimize a polycrystalline ceramic composition with low magnitude of n. For the optimized composition the value of g33 and d33 was found to be 55.56×10−3m2∕C and 291×10−12C∕N, respectively, yielding the magnitude pro...

Journal ArticleDOI
TL;DR: In this article, the authors report first principles density functional calculations of the polarizations, piezoelectric stress constants, and elastic constants for the II-VI oxides MgO, ZnO, and CdO in the wurtzite structure.
Abstract: We report first-principles density functional calculations of the polarizations, piezoelectric stress constants, and elastic constants for the II-VI oxides MgO, ZnO, and CdO in the wurtzite structure. Using our pseudopotential self-interaction corrected implementation of density functional theory, we obtain polarization values of −0.060, −0.022, and −0.10 C/m2, and piezoelectric constants, e33 (e31) of 1.64 (−0.58), 1.34 (−0.57), and 1.67 (−0.48) C/m2 for structurally relaxed MgO (with its in-plane lattice parameter fixed to that calculated for ZnO), ZnO, and CdO, respectively. The large polarization gradients between the end-point compounds in the MgO-ZnO-CdO system augur well for the production of large internal fields in ZnO-based polarization field effect transistors.

Journal ArticleDOI
TL;DR: In this paper, a novel piezoelectric cantilever bimorph micro transducer electro-mechanical energy conversion model is proposed based on the curvature basis approach.