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Showing papers on "Piezoelectricity published in 1996"



Journal ArticleDOI
TL;DR: In this article, the limitations of linear constitutive modeling and limitations of this composition of PLZT as an actuator material are examined, and the "yield" or ferroelastic switching stress is suggested as a good criteria for assessing the capability of actuator ceramics.

448 citations


Journal ArticleDOI
TL;DR: In this article, a double-beam interferometer was proposed to suppress the bending effect of the substrate bending motion in piezoelectric thin-film measurements, which was shown to resolve small displacements without using lock-in technique.
Abstract: Interferometric measurements of electric field‐induced displacements in piezoelectric thin films using single‐beam and double‐beam optical detection schemes are reported. It is shown that vibrational response measured with a single‐beam interferometer includes a large contribution of the bending motion of substrate. Therefore, it is difficult to apply single‐beam technique for piezoelectric measurements in thin films. To suppress the bending effect a high‐resolution double‐beam interferometer is proposed. The sensitivity of the interferometer is significantly improved in comparison with previously reported system. The interferometer is shown to resolve small displacements without using a lock‐in technique. An example of the interferometric capabilities is demonstrated with experimental results on electric field, frequency, and time dependences of piezoelectric response for quartz and Pb(Zr,Ti)O3 thin film.

415 citations


Journal ArticleDOI
TL;DR: In this paper, a new mechanism of electric power generation in which mechanical impact energy is transformed to electric energy by a piezoelectric transducer was proposed, and the transformation efficiency was analyzed as functions of the electromechanical coupling coefficient, the mechanical loss and the dielectric loss of the vibrator.
Abstract: We propose a new mechanism of electric power generation in which mechanical impact energy is transformed to electric energy by a piezoelectric transducer. To clarify the relationship between the input mechanical impact energy and the output electric energy in this method, we measured the electric output of a piezoelectric vibrator stimulated by an impact with a steel ball. An electrical equivalent model of the phenomenon is proposed to analyze the transformation efficiency as functions of the electromechanical coupling coefficient, the mechanical loss and the dielectric loss of the vibrator.

385 citations


Journal ArticleDOI
TL;DR: In this paper, a review of models predicting the electro-active properties of 0-3 composites is presented together with a proposal for a new mixed connectivity cubes model to be applicable to the case of high ceramic loading and/or when the ceramic grain size incorporated in the polymer matrix is comparable to the thickness of the sample.
Abstract: Ferroelectric composites are now an established alternative to conventional ferroelectric ceramic materials and to the more recently discovered ferroelectric polymers. These materials due to their unique blending of polymetric properties of mechanical flexibility, formability and low cost with high electro-active properties have been been suggested to be a viable alternative both in piezoelectric and pyroelectric transducer applications. This review is devoted to the piezoelectric and pyroelectric properties exhibited by these type of composites with a special reference to those made of ceramic particles embedded in a polymer matrix (i.e. 0-3 connectivity type composite). A review of models predicting the electro-active properties of 0-3 composites is presented together with a proposal for a new mixed connectivity cubes model to be applicable to the case of high ceramic loading and/or when the ceramic grain size incorporated in the polymer matrix is comparable to the thickness of the sample. A review of the experimental results of the piezo- and pyroelectric properties of various ferroelectric composite materials, reported by several workers, is also presented in this paper. Special reference is made to composites made from calcium modified lead titanate and poly(vinyldene fluoride-trifluorethylene) emphasizing their advantages in the poling process which is a critical phase in the process of obtaining successful electro-active 0-3 composite electrets.

266 citations


Journal ArticleDOI
TL;DR: In this paper, the authors formulated the mechanical and electric fields in a piezoelectric material around an elliptical cylinder cavity and the electric field within the cavity are formulated by complex potentials.

238 citations


Patent
07 Nov 1996
TL;DR: In this article, an energy transmission system for transmitting energy non-invasively from an external unit to an implanted medical device to recharge a battery in the medical device is presented.
Abstract: An energy transmission system for transmitting energy non-invasively from an external unit to an implanted medical device to recharge a battery in the medical device. An alternating magnetic field is generated by the external charging unit and a piezoelectric device in the implanted medical device vibrates in response to the magnetic flux to generate a voltage. The voltage is rectified and regulated to provide charging current to a rechargeable battery in the medical device. A series of piezoelectric devices may be connected in series to produce a larger voltage than can be produced by any one piezoelectric device. Acoustic waves generated by the external charging unit alternatively can be used to vibrate the piezoelectric device instead of a changing magnetic flux. The acoustic waves are generated by an external source coupled to a piezoelectric transducer.

235 citations


Journal ArticleDOI
TL;DR: In this article, the development of a dry-coupled piezoelectric transducer system for the detection of corrosion in chemical plant pipework using cylindrical Lamb waves is described.
Abstract: The development of a dry-coupled piezoelectric transducer system for the detection of corrosion in chemical plant pipework using cylindrical Lamb waves is described. It is shown that the axisymmetricL(0,2) mode at a frequency of about 70 kHz is an attractive mode to use for longdistance propagation. The results show that a ring of piezoelectric length-expander elements can be used to excite theL(0,2) mode and to suppress all the nonaxisymmetric modes. Tests have been carried out both with the piezoelectric elements bonded to the pipe and fabricated into a simple transducer which was clamped against the pipe. The performance of the dry-coupled system was very similar to that of the bonded elements. In pulse echo tests, the noise floor obtained with the dry-coupled system was less than 1% of the amplitude of the propagatingL(0,2) mode. The drycoupled transducers provide a simple, light, readily detachable system for the long-range inspection of pipework.

235 citations


Journal ArticleDOI
TL;DR: In this paper, the authors explored the special characteristics of ferroelectric materials which make them highly suitable for application as both sensors and actuators in electromechanical (smart) systems.

221 citations


Journal ArticleDOI
TL;DR: In this paper, the piezoelectric response of silicon diaphragms covered with sputter-deposited PbZr0.45Ti0.55O3 (PZT) films has been investigated in view of their application in ultrasonic micro-actuators.
Abstract: The piezoelectric response of silicon diaphragms covered with sputter-deposited PbZr0.45Ti0.55O3 (PZT) films has been investigated in view of their application in ultrasonic micro-actuators. The behaviour of resonance frequencies and quasistatic deflections has been studied as a function of membrane thickness and d.c. bias. The total stress in the films and the piezoelectric constant, d(31), have been derived by means of two different methods. The results are consistent with direct strain measurements by optical interferometry and with bulk ceramic values of identical composition.

198 citations


Journal ArticleDOI
TL;DR: In this paper, the authors measured the piezoresistive effect in the n-type wurtzite GaN films and found that the 3-5 μm thick GaN layers were deposited slightly off axis over basal plane sapphire substrates.
Abstract: We report on the measurements of the piezoresistive effect in the n‐type wurtzite GaN films. The 3–5 μm thick GaN layers were deposited slightly off axis over basal plane sapphire substrates. The static and dynamic gauge factor (GF) of these structures was measured at room temperature for both longitudinal and transverse configurations. The dynamic effect is related to a strong piezoeffect in GaN. The maximum dynamic GF observed was ∼130 (approximately four times larger than for SiC).

Journal ArticleDOI
TL;DR: In this paper, a La 3 Ga 5 SiO 14 (LGS) single crystal with dimensions of 1 or 2 inch in diameter was grown using the Czochralski technique.

Journal ArticleDOI
TL;DR: In this paper, an exact transfer matrix-based methodology for the analysis of laminated piezoelectric structures is presented, where the transfer matrix is rendered in block form by judiciously arranging the state variables and its property is exploited to minimize the computational effort.

Journal ArticleDOI
TL;DR: In this paper, heat generation in various types of multilayer PZT-based actuators was studied and it was shown that heat generation is mainly caused by ferroelectric hysteresis loss in the stress-free state.
Abstract: Multilayer piezoelectric actuators when driven under high frequency, generate significant heat, which influences the reliability and other piezoelectric properties. In this paper, heat generation in various types of multilayer PZT-based actuators was studied. Experimental results showed that heat generation is mainly caused by ferroelectric hysteresis loss in the stress-free state. A simplified analytic method was established to evaluate the temperature rise, which is useful for the design of multilayer and other high-power actuators.

Journal ArticleDOI
TL;DR: In this paper, exact solutions for the problem of piezoelectric laminates in cylindrical bending under an applied surface traction or potential are presented for several representative cases, with resulting displacement, potential, stress, and electric displacement distributions shown to demonstrate the effects of the electroelastic coupling.
Abstract: Exact solutions are presented for the problem of piezoelectric laminates in cylindrical bending under an applied surface traction or potential. An arbitrary number of elastic or piezoelectric layers can be considered in this analysis. Example problems are considered for several representative cases, with resulting displacement, potential, stress, and electric displacement distributions shown to demonstrate the effects of the electroelastic coupling.

Journal ArticleDOI
TL;DR: In this paper, the Stroh formalism was adopted to solve the two-dimensional problem of an elliptic hole in a solid of anisotropic piezoelectric material.

Journal ArticleDOI
TL;DR: In this article, the direct piezoelectric effect in fine and coarse grain barium titanate ceramics is examined as a function of the external alternating and static pressure.
Abstract: The direct piezoelectric effect in fine and coarse grain barium titanate ceramics is examined as a function of the external alternating and static pressure. It is found that domain wall vibrations contribute to the piezoelectric effect in both types of ceramics, but this contribution is smaller in the fine grain material. The external static pressure reduces domain wall contributions in the coarse grain samples and has little effect on the properties of the fine grain material. The results are consistent with the presence of a strong internal pressure in the fine grain ceramics.

Journal ArticleDOI
TL;DR: In this article, the thickness dependence of film structure and the dielectric, ferroelectric, and piezoelectric properties have been characterized over the thickness range of 1-12 μm.
Abstract: Thick films of lead zirconate titanate of the morphotropic phase boundary composition, Pb(Zr0.52Ti0.48)O3, have been fabricated on platinum-buffered silicon using a modified sol–gel spin-coating technique. Crack-free films of 12-μm thickness can be uniformly deposited on 3-in.-diameter wafers with high yield and properties comparable to those of bulk ceramics. The thickness dependence of film structure and the dielectric, ferroelectric, and piezoelectric properties have been characterized over the thickness range of 1–12 μm. A strong (100) texture develops as film thickness increases above 5 μm; the films were marked by saturation values of longitudinal piezoelectric coefficient d33, 340 pC/N; remanent polarization, 27 μC/cm2; and dielectric permittivity, 1450. PZT films in this thickness range are extremely well-suited to application as electromechanical transduction media in silicon-based microelectromechanical systems (MEMS).

Journal ArticleDOI
TL;DR: In this article, closed-form expressions for the infinite-body Green's functions for a transversely isotropic piezoelectric medium were obtained using a formulation where the three displacements and the electric potential are derived from two potential functions.

Journal ArticleDOI
TL;DR: In this article, a complete form of stress and electric displacement fields in the vicinity of the tip of an interfacial crack, between two dissimilar anisotropic piezoelectric media, was derived by using the complex function theory.
Abstract: A complete form of stress and electric displacement fields in the vicinity of the tip of an interfacial crack, between two dissimilar anisotropic piezoelectric media, is derived by using the complex function theory. New definitions of real-valued stress and electric displacement intensity factors for the interfacial crack are proposed. These definitions are extensions of those for cracks in homogeneous piezoelectric media. Closed form solutions of the stress and electric displacement intensity factors for a semi-infinite crack as well as for a finite crack at the interface between two dissimilar piezoelectric media are also obtained by using the mutual integral.

Journal ArticleDOI
TL;DR: In this paper, the piezoelectric properties of Pb(Zr,Ti)O3 thin films are investigated as a function of the number of bipolar and unipolar voltage pulses.
Abstract: Piezoelectric properties of Pb(Zr,Ti)O3 thin films are investigated as a function of the number of bipolar (switching) and unipolar (nonswitching) voltage pulses. The longitudinal piezoelectric coefficient d33 decreases with bipolar fatigue reflecting the decrease of switchable polarization. Simultaneously, a strong vertical shift of piezoelectric hysteresis loops is observed, which is considered as the buildup of fixed internal polarization due to the pinning of ferroelectric domains in a preferred orientation. Piezoelectric fatigue induced by unipolar (nonswitching) pulses is considerably smaller than the fatigue under bipolar conditions and can be described by the internal bias field which shifts piezoelectric hysteresis loops along the field axis.

Journal ArticleDOI
TL;DR: In this paper, a novel piezoelectric thin-film accelerometer has been designed and its performance has been analyzed, which can be integrated with the electronic readout and can be extended into an array of accelerometers.
Abstract: A novel piezoelectric thin-film accelerometer has been designed and its performance has been analysed. The piezoelectric thin film (PZT for example) is delineated into an array of pads to reduce the sensor capacitance. By filling the cavity around the PZT pads either with a polymer or a gas with controlled pressure, damping can be controlled. The piezoelectric thin-film material (i.e., pads) is clamped between a seismic mass and a base plate (silicon substrate). During acceleration in the axial direction the seismic mass exerts a force on the piezoelectric layer, resulting in the generation of a charge due to the piezoelectric effect. The induced charge is independent of the dimensions of the piezoelectric layer and hence of its tolerances. The generated charge is directly sensed by a charge-sensitive preamplifier that is implemented by CMOS technology on a tiny silicon chip. In principle, the proposed thin-film accelerometer can be integrated with the electronic readout and can be extended into an array of accelerometers. The dynamic response is presented and the trade-offs between several design considerations are discussed. For a specific design, a sensor sensitivity of 320 mV g(-1) and lower and upper cut-off frequencies of, respectively, 1 Hz and 0.2 MHz have been calculated. By using differential sensing, the proposed thin-film accelerometer can be further developed to include compensation for temperature and pyroelectric effects. In addition, self-test features based on the application of electrostatic forces are feasible but require more sophisticated signal processing.

Journal ArticleDOI
TL;DR: In this paper, an exact 3D solution for the problem of a simply supported rectangular homogeneous piezoelectric plate is obtained, in the framework of the linear theory of piezolectricity.
Abstract: An exact three-dimensional solution for the problem of a simply supported rectangular homogeneous piezoelectric plate is obtained, in the framework of the linear theory of piezoelectricity. The plate is made of a transversely isotropic material, is earthed on the lateral boundary, and is subjected to prescribed surface charge and tractions on the end faces. The limit of this solution as the plate thickness aspect ratio approaches zero is explicitly carried out. The analytical results obtained may constitute a reference case when developing or applying two-dimensional plate theories for the analysis of more complex piezoelectric problems. A numerical investigation in the case of a square uniformly loaded plate is also performed, in order to evaluate the influence of the thickness-to-side ratio on the three-dimensional solution of the plate problem.

Journal ArticleDOI
TL;DR: In this article, low-field piezoelectric coefficient and strain were investigated in Ca-modified PbTiO3 thin films by means of optical interferometry.
Abstract: Low‐field piezoelectric coefficient and strain were investigated in Ca‐modified PbTiO3 thin films by means of optical interferometry. A remanent piezoelectric coefficient of 70 pm/V was observed that agrees well with the values previously reported for the bulk ceramics of the same composition. The efficient poling of the films can be achieved at room temperature under the field of 300 kV/cm. Electrically induced strains as high as 0.8% were observed using a bipolar driving field of 1 MV/cm. Strain response under a unipolar driving field exhibited a good linearity and small hysteresis. These properties combined with the low dielectric constant and high dielectric strength are shown to be attractive for micromechanical applications.

Journal ArticleDOI
TL;DR: In this article, a finite element technique is used to study the stress distributions at the crack tip of a piezoelectric ceramic because of the mechanical and/or electrical loads, which is in conformity with those predicted theoretically by Sosa and Pak.

Journal ArticleDOI
TL;DR: In this paper, the mechanical response of piezoelectric cantilever beams actuated by sol-gel-derived lead zirconium titanate (PZT) thin film is reported.
Abstract: The mechanical response of piezoelectric cantilever beams actuated by sol-gel- derived lead zirconium titanate (PZT) thin film is reported. Small multilayered beams are used to analyse the converse piezoelectric effect and to measure the mechanical deflection of the beams with a standard interferometry method. Interferometric displacement measurements, electrical measurements and finite- element simulations are reported to determine the piezoelectric coefficient d(31) of the PZT thin film.

Journal ArticleDOI
TL;DR: In this article, a mathematical model based on a layerwise theory is developed for laminated composite beams with piezoelectric actuators, and a finite element model is developed.

Journal ArticleDOI
TL;DR: In this article, the theory of linear piezoelectricity is applied to solve the antiplane electroelastic problem of an orthotropic PEG ceramic strip with a finite crack, which is situated symmetrically and oriented in a direction normal to the edges of the strip.

Journal ArticleDOI
TL;DR: In this article, the authors extended discrete layer mechanics to incorporate thermal effects to account for the complete coupled mechanical, electrical, and thermal response of piezoelectric composite beams in thermal environments.
Abstract: Previously developed discrete layer mechanics are extended to incorporate thermal effects to account for the complete coupled mechanical, electrical, and thermal response of piezoelectric composite beams. Thermal effects in both the elastic and piezoelectric media are captured at the material level. This unified representation leads to an inherent capability to model both the sensory and active responses of piezoelectric composite beams in thermal environments. Finite element equations are developed and implemented for a beam element with linear shape functions. Results from the current formulation are compared with results from a conventional thermoelastic finite element analysis and classical beam theory. Additional numerical studies demonstrate capabilities of the current formulation to predict the thermal deformation of composite beams, as well as the active compensation of these thermal deformations using piezoelectric structures. The corresponding sensory response and the resultant stress state in the piezoelectric composite beam are also presented. [Amn], [Bmn], [Dmn] b [C] {D} [d] {E} [Emn] [e] {F}

Journal ArticleDOI
TL;DR: An analysis of a simply supported rectangular elastic plate forced into bending vibrations by the application of time harmonic voltages to piezoelectric actuators attached to its bottom and top surfaces is performed by using the equations of linear elasticity as mentioned in this paper.