Showing papers on "Piezoelectricity published in 2001"
TL;DR: In this article, the origin of ultrahigh piezoelectricity in the relaxor ferroelectric PbZn(1/3)Nb(2/3)-PbTiO3 was studied with an electric field applied along the [001] direction.
Abstract: The origin of ultrahigh piezoelectricity in the relaxor ferroelectric PbZn(1/3)Nb(2/3)O3-PbTiO3 was studied with an electric field applied along the [001] direction. The zero-field rhombohedral R phase starts to follow the direct polarization path to tetragonal symmetry via an intermediate monoclinic M phase, but then jumps irreversibly to an alternate path involving a different type of monoclinic distortion. Details of the structure and domain configuration of this novel phase are described. This result suggests that there is a nearby R-M phase boundary as found in the Pb(Ti,Zr)O3 system.
585 citations
TL;DR: In this paper, the extrinsic contribution to the dielectric constant of PZT films was mainly attributed to 180° domain wall motion, which increased with both film thickness and grain size.
Abstract: In this article, domain wall motion and the extrinsic contributions to the dielectric and piezoelectric responses in sol–gel derived lead zirconate titanate (PZT) films with compositions near the morphotropic phase boundary were investigated. It was found that although the films had different thicknesses, grain sizes, and preferred orientations, similar intrinsic dielectric constants were obtained for all films between 0.5 and 3.4 μm thick. It was estimated that about 25%–50% of the dielectric response at room temperature was from extrinsic sources. The extrinsic contribution to the dielectric constant of PZT films was mainly attributed to 180° domain wall motion, which increased with both film thickness and grain size. In studies on the direct and converse longitudinal piezoelectric coefficients of PZT films as a function of either stress or electric driving field, it was found that the ferroelastic non-180° domain wall motion was limited. Thus extrinsic contributions to the piezoelectric response were small in fine grain PZT films (especially those under 1.5 μm in thickness). However, as the films became thicker (>5μm), nonlinear behavior between the converse piezoelectric coefficient and the electric driving field was observed. This indicated that there was significant ferroelectric non-180° domain wall motion under high external excitation in thicker films. The activity of the non-180° domain walls was studied through non-180° domain switching. For fine grain films with film thicknesses less than 2 μm, non-180° switching was negligible. Transmission electron microscopy plan-view micrographs evidenced non-180° domain fringes in these films, where the vast majority of grains were 50–100 nm in diameter and showed a single set of domain fringes. Taken together, these measurements suggest that the pinning of non-180° domain walls is very strong in films with thickness less than 2 μm. In thicker films, non-180° domain switching was evidenced when the poling field exceeded a threshold field. The threshold field decreased with an increase in film thickness, suggesting more non-180° domain wall mobility in thicker films. Non-180° domain switching in large grained PZT films was found to be much easier and more significant than in the fine grained PZT films.
480 citations
TL;DR: In this paper, the authors present an overview of experimental evidence and present understanding of nonlinear dielectric, elastic and piezoelectric relationships in PEG ceramics.
Abstract: The paper presents an overview of experimental evidence and present understanding of nonlinear dielectric, elastic and piezoelectric relationships in piezoelectric ceramics. This topic has gained an increasing recognition in recent years due to the use of such materials under extreme operating conditions, for example in electromechanical actuators and high power acoustic transducers. Linear behaviour is generally confined to relatively low levels of applied electric field and stress, under which the dielectric, elastic and piezoelectric relationships are described well by the standard piezoelectric constitutive equations. Nonlinear relationships are observed above certain ‘threshold’ values of electric field strength and mechanical stress, giving rise to field and stress-dependent dielectric (e), elastic (s) and piezoelectric (d) coefficients. Eventually, strong hysteresis and saturation become evident above the coercive field/stress due to ferroelectric/ferroelastic domain switching. The thermodynamic method provides one approach to describing nonlinear behaviour in the ‘intermediate’ field region, prior to large scale domain switching, by extending the piezoelectric constitutive equations to include nonlinear terms. However, this method seems to fail in its prediction of the amplitude and phase of high frequency harmonic components in the field-induced polarisation and strain waveforms, which arise directly from the nonlinear dielectric and piezoelectric relationships. A better fit to experimental data is given by the empirical Rayleigh relations, which were first developed to describe nonlinear behaviour in soft magnetic materials. This approach also provides an indication of the origins of nonlinearity in piezoelectric ceramics, in terms of ferroelectric domain wall translation (at intermediate field/stress levels) and domain switching (at high field/stress levels). The analogy with magnetic behaviour is also reflected in the use of Preisach-type models, which have been successfully employed to describe the hysteretic path-dependent strain-field relationships in piezoelectric actuators. The relative merits and limitations of the different modelling methods are compared and possible areas of application are identified.
447 citations
TL;DR: The elastic, piezoelectric, and dielectric constants of 0.67Pb(Mg1/3Nb2/3)O3 and 0.33PbTiO3 domain engineered single crystal were determined experimentally by using ultrasonic and resonance methods as mentioned in this paper.
Abstract: The elastic, piezoelectric, and dielectric constants of 0.67Pb(Mg1/3Nb2/3)O3–0.33PbTiO3 domain engineered single crystal were determined experimentally by using ultrasonic and resonance methods. It was confirmed that the single crystal system has large electromechanical coupling coefficient k33 (∼94%) and piezoelectric constant d33 (∼2800 pC/N) if the poling is done along the [001] of pseudocubic directions. A soft shear mode with a velocity of 880 m/s was observed in the [110] direction with displacement in [110]. Using the measured data, the orientation dependence of phase velocities and electromechanical coupling coefficients were calculated. The origin of experimental errors and their influence on measured results are also examined.
422 citations
TL;DR: A material is reported that shows a further increase in electrostriction by two orders of magnitude: ultrathin (less than 100 nanometres) ferroelectric liquid-crystalline elastomer films that exhibit 4 per cent strain at only 1.5 MV m-1.
Abstract: Mechanisms for converting electrical energy into mechanical energy are essential for the design of nanoscale transducers, sensors, actuators, motors, pumps, artificial muscles, and medical microrobots. Nanometre-scale actuation has to date been mainly achieved by using the (linear) piezoelectric effect in certain classes of crystals (for example, quartz), and 'smart' ceramics such as lead zirconate titanate. But the strains achievable in these materials are small--less than 0.1 per cent--so several alternative materials and approaches have been considered. These include grafted polyglutamates (which have a performance comparable to quartz), silicone elastomers (passive material--the constriction results from the Coulomb attraction of the capacitor electrodes between which the material is sandwiched) and carbon nanotubes (which are slow). High and fast strains of up to 4 per cent within an electric field of 150 MV x m(-1) have been achieved by electrostriction (this means that the strain is proportional to the square of the applied electric field) in an electron-irradiated poly(vinylidene fluoride-trifluoroethylene) copolymer. Here we report a material that shows a further increase in electrostriction by two orders of magnitude: ultrathin (less than 100 nanometres) ferroelectric liquid-crystalline elastomer films that exhibit 4 per cent strain at only 1.5 MV x m(-1). This giant electrostriction was obtained by combining the properties of ferroelectric liquid crystals with those of a polymer network. We expect that these results, which can be completely understood on a molecular level, will open new perspectives for applications.
398 citations
TL;DR: PVDF piezo polymers are new, valuable materials for sensing and actuating applications as mentioned in this paper and are strong candidates for new sensors that cannot be realized with piezoceramics or single crystals.
Abstract: PVDF piezo polymers are new, valuable materials for sensing and actuating applications. These materials are strong candidates for new sensors that cannot be realised with piezoceramics or single crystals. The combination of the mechanical properties of a plastic material with those of a piezoelectric material led to new sensors and transducers whose design is not easy. For this reason, the characteristics and properties of piezo polymer are described as well as basic knowledge that engineers need for technical use.
322 citations
TL;DR: In this article, a small ac voltage (V-ac sin omegat) was applied to the tip to measure the amplitude (A(omega)) and phase (Phi (omega) of the first harmonic signal as a function of V-dc.
Abstract: The contrast mechanisms of domain imaging experiments assisted by atomic force microscope (AFM) have been investigated by model experiments on nonpiezoelectric (silicon oxide) and piezoelectric [Pb(Zr,Ti)O-3] thin films. The first step was to identify the electrostatic charge effects between the tip, the cantilever, and the sample surface. The second step was to explore the tip-sample piezoelectric force interaction. The static deflection of the cantilever was measured as a function of dc bias voltage (V-dc) applied to the bottom electrode (n-type Si wafers) for noncontact and contact modes. In addition, a small ac voltage (V-ac sin omegat) was applied to the tip to measure the amplitude (A(omega)) and phase (Phi (omega)) of the first harmonic (omega) signal as a function of V-dc. By changing from the noncontact to the contact mode, a repulsive contribution to the static deflection was found in addition to the attractive one and a 180 degrees phase shift in Phi (omega) was observed. These results imply that in the contact mode the cantilever buckling is induced by the capacitive force between the cantilever and the sample surface. This interaction adds to the tip-sample piezoelectric interaction thereby overlapping the obtained tip vibration signal. Therefore, the antiparallel ferroelectric domain images obtained at zero dc bias voltage will show a variation in A(omega) but a negligible one in Phi (omega). The capacitive force contribution to the tip vibration signal was further verified in piezoelectric hysteresis loop measurement assisted by the AFM. The observed vertical offset of the loops was explained by the contact potential difference between the cantilever and the bottom electrode. The shape of the curve could be explained by the capacitive force interaction combined with the tip-sample piezoelectric interaction. The experimental results obtained in this study support the interpretation of the cantilever-sample capacitive force contribution to the tip vibration signal in ferroelectric domain imaging experiments using AFM as a probing tool. The use of a large area top electrode between the tip and the sample resulted in the elimination of the electrostatic cantilever-sample interaction with negligible degradation of the domain contrast. This method proved to be successful because the cantilever-sample interaction was hardly detected and only the tip-sample interaction was observed. (C) 2001 American Institute of Physics.
305 citations
TL;DR: In this paper, the dependence of macroscopic polarization on composition and strain in wurtzite III-V nitride ternary alloys using ab initio density-functional techniques was studied.
Abstract: We study the dependence of macroscopic polarization on composition and strain in wurtzite III-V nitride ternary alloys using ab initio density-functional techniques. The spontaneous polarization is characterized by a large bowing, strongly dependent on the alloy microscopic structure. The bowing is due to the different response of the bulk binaries to hydrostatic pressure and to internal strain effects (bond alternation). Disorder effects are instead minor. Deviations from parabolicity (simple bowing) are of order 10% in the most extreme case of AlInN alloys, much less at all other compositions. Piezoelectric polarization is also strongly nonlinear. At variance with the spontaneous component, this behavior is independent of microscopic alloy structure or disorder effects, and due entirely to the nonlinear strain dependence of the bulk piezoelectric response. It is thus possible to predict the piezoelectric polarization for any alloy composition using the piezoelectricity of the parent binaries.
289 citations
TL;DR: In this paper, the relationship between elastic strain gradient and electric polarization was investigated in the relaxor ferroelectric lead magnesium niobate ceramic, and it was shown that flexoelectric polarization is linearly proportional to the applied strain gradient.
Abstract: The relationship between elastic strain gradient and electric polarization was investigated in the relaxor ferroelectric lead magnesium niobate ceramic. Experimental studies indicated that flexoelectric polarization is linearly proportional to the applied strain gradient, and the flexoelectric coefficient μ12 is calculated to be 4×10−6 C/m, which is much higher than the early phenomenological estimations.
254 citations
TL;DR: In this paper, an orthorhombic ferroelectric phase was observed in 0.67Pb(Mg1/3Nb2/3)O3−0.33PbTiO3 single crystals.
Abstract: We report on the observation of an orthorhombic ferroelectric phase in 0.67Pb(Mg1/3Nb2/3)O3–0.33PbTiO3 single crystals, whose polarization is along 〈011〉 direction and stability can be altered by poling conditions. We studied the piezoelectric properties on poled 〈011〉 crystals, in both monodomain and polydomain states, and found that the piezoelectric d32 coefficient, which is the piezoelectric response in perpendicular to the poling direction, is positive in both cases. Based on the phenomenological theory, we show that this is possible in a crystal with the electrostrictive coefficients Q11>Q44–Q12.
229 citations
TL;DR: In this article, the dielectric, ferroelectric and piezoelectric properties of bismuth sodium titanate (Bi1/2Na 1/2)TiO3 (BNT) were studied for a candidate as lead-free, lead free, and non-piercing ceramics, and it was shown that Mn ions exist in the grain, and substitute for the A- or B-site of the perovskite structure.
Abstract: Microstructure, dielectric, ferroelectric and piezoelectric properties of bismuth sodium titanate (Bi1/2Na1/2)TiO3 (BNT) were studied for a candidate as lead-free piezoelectric ceramics. In the case of Mn addition, the Curie temperature, Tc, decreases rapidly with increasing amount of doped MnCO3. The resistivity, ρ, is enhanced to 3×1014 (Ωcm) (at 40°C) for BNT+MnCO3 0.2 (wt.%) and electromechanical coupling factor, k33, was obtained the relatively high value under the condition of the low poling field, Ep for the Mn-doped BNT ceramics. It seems that Mn ions exist in the grain, and substitute for the A- or B-site of the perovskite structure, and eject Bi ions to the air.
TL;DR: In this paper, a dynamic admittance model describing the electromechanical behavior of piezoelectric beam resonators is presented, and the results indicate that the resonators offer significant potential for high-frequency applications.
Abstract: Piezoelectric micromechanical beam resonators are investigated for application to electromechanical filters. The derivation of a dynamic admittance model describing the electromechanical behavior of the resonators is presented. Predictions from this model indicate that piezoelectric beam resonators offer significant potential for high-frequency applications. Using a simple three-mask fabrication process based on zinc oxide active films, doubly-clamped piezoelectric beam resonators with center frequencies ranging from 158 kHz to 1.18 MHz are reported. Resonators with both ZnO and SiO 2 substrates have been realized, and triple-beam configurations investigated for reducing mechanical anchor losses. Measured quality factors range from Q =3700 at 158 kHz to Q =930 at 1.18 MHz.
TL;DR: In this article, the possible domain states of perovskite ferroelectrics under applied fields are reviewed and, as an illustration, a phenomenological study of barium titanate is carried out.
Abstract: The possible domain states of perovskite ferroelectrics under applied fields are reviewed and, as an illustration, a phenomenological study of barium titanate is carried out. Electric field-temperature phase diagrams, the polarization, and the lattice strain of barium titanate single crystals are calculated from the Landau–Ginzburg–Devonshire theory of ferroelectrics for applied fields up to 20 MV m−1 and for temperatures from 1 to 450 K. The calculations are carried out for fields applied along the pseudocubic [001], [101], and [111] axes, revealing the temperature and field dependence of all the ferroelectric phase transitions. Large piezoelectric coefficients can be identified close to field-induced transitions. Good agreement is seen with experimental data for the piezoelectric coefficient parallel to [001] over a wide range of temperature. The series of transitions predicted for increasing field parallel to [111] at room temperature is qualitatively similar to that observed experimentally but with so...
TL;DR: In this paper, the form of the electric potential field in the piezoelectric layer is assumed such that the Maxwell static electricity equation is satisfied, based on the Kirchhoff plate model.
Abstract: This paper deals with the vibration analysis of a circular plate surface bonded by two piezoelectric layers, based on the Kirchhoff plate model. The form of the electric potential field in the piezoelectric layer is assumed such that the Maxwell static electricity equation is satisfied. The validation of the theoretical model is done by comparing the resonant frequencies of the piezoelectric coupled circular plate obtained by the theoretical model and those obtained by finite-element analysis. The mode shape of the electric potential obtained from free vibration analysis is generally shown to be non-uniform in the radial direction in contrast to what is commonly assumed. The piezoelectric layer is shown to have an effect on the frequencies of the host structure. The proposed model for the analysis of a coupled piezoelectric circular plate provides a means to obtain the distribution of electric potential in the piezoelectric layer. The model provides design reference for piezoelectric material application, such as an ultrasonic motor.
TL;DR: In this paper, the influence of the corona-charging process on the piezoelectric transducer coefficient d33 of a cellular electret film has been investigated, and the effect of the gas inside the voids has also been studied.
Abstract: The influence of the corona-charging process on the piezoelectric transducer coefficient d33 of a cellular electret film has been investigated. An increased corona voltage can be considered as a way to enhance the charge density and thus also the resulting piezoelectric effect. Higher corona-charging voltages are possible with increased ambient pressure or in suitable dielectric gases. The effect of the gas inside the voids has also been studied. Enhanced transducer coefficients were obtained by corona charging in N2 or N2O gas atmospheres at 100-450 or 100-140 kPa pressures, respectively. The highest transducer coefficients of about 790 pCN-1 were obtained when N2 gas was filled into the voids of a cellular polymer film by means of consecutive vacuum and high-pressure treatments at 295 or 313 K.
TL;DR: In this article, a negative shift of the initial piezoelectric hysteresis loop was observed in lead zirconate titanate mesoscopic structures. The shift is most probably due to the pinning of ferroelectric domains at the free lateral surface and ferroelectrode interface.
Abstract: Piezoresponse scanning force microscopy measurements performed on lead zirconate titanate mesoscopic structures revealed a negative shift of the initial piezoelectric hysteresis loop. The shift is dependent on the size of the structure and is most probably due to the pinning of ferroelectric domains at the free lateral surface and ferroelectric–electrode interface. Considering a simple model, the thickness of the pinned domain layers is found to be about 15 and 70 nm at the ferroelectric–electrode interface and lateral free surface, respectively.
TL;DR: In this paper, it was shown that at room temperature, the 067 PMN-033 PT crystals near the morphotropic phase boundary composition present not only a rhombohedral $3m$ phase but also a monoclinic m phase with various angles of polarization rotation.
Abstract: In the principle of optical crystallography and crystal symmetry, it is found that at room temperature, the 067 PMN-033 PT crystals near the morphotropic phase boundary composition present not only a rhombohedral $3m$ phase but also a monoclinic m phase with various angles of polarization rotation, the third ferroelectric phase in the PMN-PT solid solution system The polarization rotation readily driven by composition suggests that it can be easily induced by electric field as well, thereby providing the structure base of the ultrahigh piezoelectric performance of 067 PMN-033 PT single crystals
Patent•
13 Nov 2001
TL;DR: In this article, a piezoelectric ceramic composition was characterized in that the composition formula is represented by Pbx Bay Srz (B3+1/2B5+1 /2B3 + 1/2b5+ 1 /2) a Tib Zrc}O3, 093, the ingredient of B3+ is one kind of Sb, Bi, and La, and principal ingredient of Nb, and Ta
Abstract: PROBLEM TO BE SOLVED: To provide a piezoelectric ceramic composition having high piezoelectro striction constant, excellent in mechanical strength, especially suitable for a piezoelectric effect applied electric parts for an actuator SOLUTION: The piezoelectric ceramic composition is characterized in that the composition formula is represented by Pbx Bay Srz (B3+1/2B5+1/2) a Tib Zrc}O3, 093 , the ingredient of B3+ is one kind of Sb, Bi, and La, and principal ingredient of B5+ is one kind of Nb, and Ta
TL;DR: In this paper, three different electric shunt circuits are analyzed and their performances are compared, in particular, the optimal values of the electric components belonging to each shunt circuit and the corresponding exponential time decay rates of the free vibrations relevant to the controlled structural eigenmode are explicitly determined, also taking into account the inherent structural damping.
Abstract: Vibration damping of an elastic structure can be obtained by bonding a piezoelectric actuator onto the vibrating structure, and by shunting the actuator to a suitable electric resonant circuit, tuned to the structural eigenmode to be damped. The achievable damping depends on the particular electric circuit used. In this paper three different electric shunt circuits are analyzed and their performances are compared. In particular, the optimal values of the electric components belonging to each shunt circuit and the corresponding exponential time decay rates of the free vibrations relevant to the controlled structural eigenmode are explicitly determined, also taking into account the inherent structural damping. Finally, some experimental results are reported, obtained by using two of the shunt circuits analyzed, which are in good agreement with the theoretical predictions.
TL;DR: In this paper, the effective elastic, piezoelectric and dielectric properties of reinforced PIE composite materials with unidirectional cylindrical fibres periodically distributed in two directions at an angle π/3 by means of the asymptotic homogenization method were determined.
Abstract: The purpose of this paper is to determine the effective elastic, piezoelectric and dielectric properties of reinforced piezoelectric composite materials with unidirectional cylindrical fibres periodically distributed in two directions at an angle π/3 by means of the asymptotic homogenization method. Each periodic cell of the medium is a binary piezoelectric composite wherein both constituents are homogeneous piezoelectric materials with transversely isotropic properties. This paper makes use of some results obtained in Part I. Relatively simple closed-form expressions for the overall properties are obtained by means of potential methods of a complex variable and Weierstrass elliptic and related functions. Schulgasser universal type of relations are derived in a simple new way by means of the homogenized asymptotic method. The number of local problems to get all coefficients is two. The numerical computation of these effective properties is simple.
TL;DR: In this paper, a theoretical fracture model for brittle piezoelectric and dielectric materials is developed consistent with standard features of elasticity and Dielectricity, and the influence of electric field and mechanical loading is considered in this approach.
Abstract: A theoretical fracture mechanics for brittle piezoelectric and dielectric materials is developed consistent with standard features of elasticity and dielectricity. The influence of electric field and mechanical loading is considered in this approach and a Griffith style energy balance is used to establish the relevant energy release rates. Results are given for a finite crack in an infinite isotropic dielectric and for steady state cracking in a piezoelectric strip. In the latter problem, the effect of charge separation in the material and discharge in the crack are considered. Observations of crack behavior in piezoelectrics under combined mechanical and electrical load are discussed to assess which features of the theory are useful.
TL;DR: In this paper, the phase velocity equations of the Love wave propagation and the stress fields in the layered piezoelectric structure are obtained for electrical open and short cases on the free surface, respectively.
TL;DR: In this paper, the Preisach model and its recent physical interpretation in terms of moving domain wall in a stochastically described pinning field are reviewed, and new expressions for piezoelectric nonlinear behavior departing from the classical linear dependence are derived using a more complex distribution.
Abstract: Piezoelectric response nonlinearity is approached using the Preisach description of hysteretic systems as collection of distributed bistable units. The Preisach model and its recent physical interpretation in terms of moving domain wall in a stochastically described pinning field are reviewed. It is shown that such an approach can effectively render not only the piezoelectric coefficient field dependences but also the field-response hysteresis, especially in the well-known case of linear piezoelectric field dependence (i.e., Rayleigh's law) where the bistable units are distributed homogeneously. New expressions for piezoelectric nonlinear behavior departing from the classical linear dependence are then derived using a more complex distribution and are qualitatively compared to experimental data for piezoelectric materials as varied as lead titanate, strontium bismuth titanate, and lead zirconate titanate. Finally, these expressions are shown to be adequate for the description of various piezoelectric coefficient behaviors such as: polynomial dependence on the applied field, dc field effect on nonlinear contributions, and threshold field for nonlinearity. (C) 2001 American Institute of Physics.
TL;DR: In this article, the effect of prestress on the nonlinear dielectric and piezoelectric response of lead zirconate-lead titanate (PZT-5H) ceramic is studied.
Abstract: The effect of prestress on the nonlinear dielectric (polarization) and piezoelectric (strain) response of lead zirconate–lead titanate (PZT–5H) piezoelectric ceramic is studied. The response to bipolar (−2/+2 MV/m) and unipolar (0/+2 MV/m, −0.4/+2 MV/m) electric field under constant prestress (up to 175 MPa) is experimentally evaluated. In the bipolar regime, prestress mainly influences the first non-180° process. In the unipolar regime, the dielectric and piezoelectric response achieve maximum values near 50–60 MPa because the prestress increases the number of available non-180° domains. A detailed description of the effect of the prestress on electro–mechanical response is provided in terms of non-180° domain wall motion. Based on rule of mixtures formulation, an analytical model is developed to estimate the optimum prestress value for the unipolar electric loading condition. It is found that the dielectric and piezoelectric response of the material is proportional to the volume fraction of the non-180°...
TL;DR: In this article, a modified classical lamination theory (CLT) was developed to account for piezoelectric coupling terms under applied electric field, which is capable of predicting the stress field and out-of-plane displacement of laminated PDE layers.
TL;DR: In this article, a closed-cell polypropylene polymer foams with a quasistatic piezoelectric d33 coefficient about 250 pC/N and a dynamic d33 coefficients of 140 pC /N at 600 kHz were presented.
Abstract: Charged closed-cell polypropylene polymer foams are highly sensitive and broadband piezoelectric materials with a quasistatic piezoelectric d33 coefficient about 250 pC/N and a dynamic d33 coefficient of 140 pC/N at 600 kHz. The piezoelectric coefficient is much larger than that of ferroelectric polymers, like polyvinylidene fluoride, and compares favorably with ferroelectric ceramics, such as lead zirconate titanate. The pyroelectric coefficient p3=0.25 μC/m2 K is small in comparison to ferroelectric polymers and ferroelectric ceramics. The low density, small pyroelectric coefficient and high piezoelectric sensitivity make charged polymer foams attractive for a wide range of sensor and transducer applications in acoustics, air-borne ultrasound, medical diagnostics, and nondestructive testing.
TL;DR: In this article, the electrostriction coefficients of a number of ferroelectric films including PbZrxTi1-xO3(PZT), 0.9PbMg(1/3)Nb(2/3)-O(3)-0.1PbTiO(4), and SrBi2Ta2O9(SBT) are investigated using laser interferometry combined with conventional dielectric measurements.
Abstract: Electromechanical properties of a number of ferroelectric films including PbZrxTi1-xO3(PZT), 0.9PbMg(1/3)Nb(2/3)O(3)-0.1PbTiO(3)(PMN-PT), and SrBi2Ta2O9(SBT) are investigated using laser interferometry combined with conventional dielectric measurements. Effective electrostriction coefficients of the films, Q(eff), are determined using a linearized electrostriction equation that couples longitudinal piezoelectric coefficient, d(33), with the polarization and dielectric constant. It is shown that, in PZT films, electrostriction coefficients slightly increase with applied electric field, reflecting the weak contribution of non-180 degrees domains to piezoelectric properties. In contrast, in PMN-PT and SBT films electrostriction coefficients are field independent, indicating the intrinsic nature of the piezoelectric response. The experimental values of Q(eff) are significantly smaller than those of corresponding bulk materials due to substrate clamping and possible size effects. Electrostriction coefficients of PZT layers are shown to depend strongly on the composition and preferred orientation of the grains. In particular, Q(eff) of (100) textured rhombohedral films (x = 0.7) is significantly greater than that of (111) layers. Thus large anisotropy of the electrostrictive coefficients is responsible for recently observed large piezoelectric coefficients of (100) textured PZT films. Effective electrostriction coefficients obtained by laser interferometry allow evaluation of the electromechanical properties of ferroelectric films based solely on the dielectric parameters and thus are very useful in the design and fabrication of microsensors and microactuators. (C) 2001 American Institute of Physics.
TL;DR: In this paper, the microstructural, dielectric and piezoelectric properties of the (1-X) (K.5Bi0.5) and (X) KNbO3 systems were studied in order to find new lead-free piezel-free ceramic materials.
Abstract: The microstructural, dielectric and piezoelectric properties of the (Na0.5Bi0.5)TiO3–NaNbO3 and (K0.5Bi0.5)TiO3–KNbO3 systems were studied in order to find new lead-free piezoelectric ceramic materials. In the (1-X) (K0.5Bi0.5)TiO3–(X) KNbO3 system, it was confirmed from the measurements of the electromechanical coupling factor, Kp, that piezoelectricity occurred within the wide compositional range between X=0 and 0.35. The sample with X=0.075 showed a maximum Kp of 15.1%. However, the expected morphotropic phase boundaries were not found in the (Na0.5Bi0.5)TiO3 or (K0.5Bi0.5)TiO3 rich side of the solid solution systems.
01 Sep 2001
TL;DR: In this article, the authors present a brief introduction of the history of piezoelectricity and a discussion on processing of the ceramic and development of the constitutive relations that define the behavior of a polycrystalline material.
Abstract: This review explores piezoelectric ceramics analysis and characterization. The focus is on polycrystalline ceramics; therefore, single crystals, polymeric materials and organic/inorganic composites are outside the scope of this review. To thoroughly grasp the behavior of a piezoelectric polycrystalline ceramic, a basic understanding of the ceramic itself should not be overlooked. To this end, we have presented a brief introduction of the history of piezoelectricity and a discussion on processing of the ceramic and development of the constitutive relations that define the behavior of a piezoelectric material. We have attempted to cover the most common measurement methods as well as introduce parameters of interest. Excellent sources for more in-depth coverage of specific topics can be found in the bibliography. In most cases, we refer to lead zirconate titanate (PZT) to illustrate some of the concepts since it is the most widely used and studied piezoelectric ceramic to date.