Showing papers on "Lead zirconate titanate published in 2001"
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: 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: In this article, the authors investigated the magnetoelectric properties of a composite with lead Zirconate Titanate (PZT) and Ni-ferrite, and reported that the composite added with 20 wt.% amount of Ni- ferrite, sintered at 1250°C for 2 hours, had the highest voltage coefficient of 115 mV/cm · Oe at room temperature.
Abstract: Piezoelectric and magnetoelectric properties of magnetoelectric particulate composites with Lead Zirconate Titanate (PZT) and Ni-ferrite were investigated. The maximum magnetoelectric voltage coefficient, (dE/dH)max, increased with higher sintering temperature up to 1250°C. Composites sintered at 1300°C, had dissolution of Fe ions into PZT, or interdiffusion between PZT and ferrite. Connectivity of the ferrite particles and sintering temperature were important factors for fabrication of this particulate composite. The composite added with 20 wt.% amount of Ni-ferrite, sintered at 1250°C for 2 hours, had the highest magnetoelectric voltage coefficient of 115 mV/cm · Oe at room temperature. This value is comparable to that of the BaTiO3-CoFe2O4 based composites reported by Philips laboratory, and is 44% higher than other magnetoelectric particulate composites.
310 citations
TL;DR: Magnetoelectric laminate composites were constructed by stacking and bonding together a PZT disk and two layers of Terfenol-D disks with different directions of magnetostriction as mentioned in this paper.
Abstract: Magnetoelectric laminate composites of piezoelectric/magnetostrictive materials were prepared by stacking and bonding together a PZT disk and two layers of Terfenol-D disks with different directions of magnetostriction. These composites were studied to investigate (i) dependence on the magnetostriction direction of the Terfenol-D disk and (ii) dependence on the direction of the applied ac magnetic field. Three different types of assemblies were prepared by using two types of disks: one with magnetostriction along the radial direction, the other with magnetostriction along the thickness direction. The maximum magnetoelectric voltage coefficient (dE/dH) of 5.90 V/cm·Oe was obtained for a design where the composite was made by two Terfenol-D layers with a radial magnetostriction direction.
253 citations
TL;DR: In this paper, the influence of grain size and domain configuration on the microscopic and macroscopic electromechanical properties of soft lead zirconate titanate (PZT) ceramics were studied.
207 citations
189 citations
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.
168 citations
TL;DR: In this article, the authors used a similar approach to prepare a wide range of inorganic oxides, semiconductors and metal-based mesophases and nanoparticles with mesostructured interiors.
Abstract: rise to mesoporous nanoparticles with radial channels. The uniform fragment length within the interior of the nanoparticles can be explained by the radial nature of the deformation field around each defect, or site-specific breakage of the 300 nm long native TMV rods. Indeed, chemical degradation of TMV does produce a stable fragment about 50 nm in length, which is similar in size to those encapsulated in the silica shell of the nanoparticles. However, we observed only a random distribution of particle lengths in control samples containing broken TMV tubes. Further work is in progress to confirm the model. In conclusion, nematic liquid crystals of TMV can be used to prepare silica mesostructures and nanoparticles with parallel or radial arrays of linear channels, respectively. The mesostructures are produced as micrometer-size inverse replicas of the nematic phase, and have a periodicity of approximately 20 nm, which is larger than that generally attainable by current methods. In contrast, the nanoparticles are less than 150 nm in size and consist of a dense silica core surrounded by an unusual radial array of mineralized TMV fragments, 50 nm in length. The channeled nanoparticles are produced at lower reactant concentrations and appear to originate from topological defects associated with the deformation and fracturing of silica±TMV clusters as the liquid crystalline state is re-established in the reaction mixture. The general stability of TMV liquid crystals suggests that it should be possible to use a similar approach to prepare a wide range of inorganic oxides, semiconductors and metal-based mesophases and nanoparticles with mesostructured interiors.
163 citations
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.
139 citations
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.
133 citations
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 article, the pyroelectric thin films of lead zirconate titanate (PbZr0.3Ti0.7)1-xMnx)O3 have been prepared using sol-gel processing techniques.
Abstract: Thin films of ferroelectric lead zirconate titanate (PbZr0.3Ti0.7O3 PZT30/70) and manganese-doped lead zirconate titanate ((Pb(Zr0.3Ti0.7)1-xMnx)O3, where x = 0.01, PM01ZT30/70; and x = 0.03, PM03ZT30/70) have been prepared using sol-gel processing techniques. These materials can be used as the pyroelectric thin films in uncooled infrared detectors. The thin films were prepared via a sol-gel route based on a hybrid solvent of methanol and ethanol with acetic acid, ethanolamine and ethylene glycol as additives. The final solution is non-moisture sensitive and stable. Films deposited on Pt/Ti/SiO2/Si substrates and annealed on a hot plate at 500-530 °C for a few minutes were seen to fully crystallize into the required perovskite phase and showed excellent ferroelectric behaviour, demonstrated by reproducible hysteresis loops (Pr = 33-37 µC cm-2, Ec( + ) = 70-100 kV cm-1, Ec(-) = -170 to -140 kV cm-1). The pyroelectric coefficient (p) was measured using the Byer-Roundy method. At 20 °C, p was 2.11×10-4 C m-2 K-1 for PZT30/70, 3.00×10-4 C m-2 K-1 for PM01ZT30/70 and 2.40×10-4 C m-2 K-1 for PM03ZT30/70 thin films. The detectivity figure-of-merit (FD) was 1.07×10-5 Pa-0.5 for PZT30/70, 3.07×10-5 Pa-0.5 for PM01ZT30/70 and 1.07×10-5 Pa-0.5 for PM03ZT30/70. These figures compare well with values reported previously.
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.
TL;DR: In this article, the phase transitions and intrinsic ferroelectric properties of the lead zirconate titanate solid solution system have been studied theoretically using the Landau-Ginsburg-Devonshire free energy approach.
Abstract: Bond contraction in the surface layers induces a compressive stress on the inner part of a grain and results in a size effect for ferroelectric materials in the nanometer size range. By using the Landau-Ginsburg-Devonshire free energy approach, the phase transitions and intrinsic ferroelectric properties of the lead zirconate titanate solid solution system have been studied theoretically. It is found that, due to the surface bond contraction, the phase stability is affected by grain size and the size-dependent properties show differences in different phases.
TL;DR: In this article, a clamped-clamped beam design with sol-gel lead zirconate titanate (PZT) actuator and sensor, PECVD silicon dioxide as the resonant beam structure, and platinum as the top and bottom electrode was demonstrated.
Abstract: Piezoelectric actuation and sensing of suspended single-beam microelectromechanical system (MEMS) resonant filters is demonstrated. Resonant frequencies between 171 kHz and 9.2 MHz were observed for resonators with dimensions of 6–20 μm wide and 25–400 μm long. Operation was demonstrated from a vacuum pressure of 20 mTorr to atmospheric with drive voltages as low as 2.5 mV and a dynamic range of greater than 40 dB. Loaded quality factors (Qs) greater than 1000 resulted at 9.2 MHz and a 20 mTorr pressure. A 20 kHz tuning range resulting from the piezoelectric poling conditions and a 75 ppm/K frequency temperature dependency was observed. The resonators utilize a clamped–clamped beam design with sol–gel lead zirconate titanate (PZT) as the piezoelectric actuator and sensor, PECVD silicon dioxide as the resonant beam structure, and platinum as the top and bottom electrode. The effects of operating temperature, operating pressure, poling condition, and drive voltage are reported.
TL;DR: In this paper, a transparent Pb(Zr, Ti)O3 (PZT) thin film with over 1 µm thickness was deposited by the aerosol deposition method (ADM).
Abstract: Transparent Pb(Zr, Ti)O3 (PZT) thin films with over 1 µm thickness were deposited by the aerosol deposition method (ADM). The transparency of the PZT thin film deposited at room temperature strongly depended on the kinds of carrier gases and the particle flow velocity. The color of the film became black if He gas was used as a carrier gas, and became transparent using N2, O2 or air gases, which were difficult to electrically discharge during the impacting of particles. The transmittance values in the 0.5–0.8 µm wavelength region of as-deposited 2-µm-thick PZT thin films on indium tin oxide (ITO) substrate were 70–80%. After annealing at 600°C, the remanent polarizations and the coercive fields of PZT thin films were 36 µC/cm2 and 89 kV/cm, respectively. With increasing carrier gas velocity, the remanent polarization decreased and the coercive field increased.
TL;DR: Lead niobium zirconate titanate (PNZT) pastes with tailored rheological properties have been developed for direct-write fabrication of thick-film capacitor elements in highly integrated, multifunctional electroceramic devices as discussed by the authors.
Abstract: Lead niobium zirconate titanate (PNZT) pastes with tailored rheological properties have been developed for direct-write fabrication of thick-film capacitor elements in highly integrated, multifunctional electroceramic devices. Such pastes exhibited pseudoplastic behavior with a low shear apparent viscosity of roughly 1 10 6 cP. On aging, the degree of shear thinning and the low shear apparent viscosity decreased. Pastes prepared from as-received powders attained printable, steady-state viscosities of 2 10 5 cP after 50 days of aging. In contrast, pastes prepared from dispersant-coated powders showed no measurable rheological changes after 1 day of aging. Square elements were patterned on dense alumina substrates or Teflon sheets. Leveling behavior as a function of time for single line prints, and the resulting surface topographies of dried PNZT films were measured by laser profilometry. PNZT layers sintered at varying temperatures between 950° and 1050°C fo r5hi neither air or a lead-rich atmosphere yielded porous microstructures as revealed by scanning electron microscopy (SEM). Such layers exhibited dielectric constants (K) of 1400 –1570 at 1 kHz with dissipation factors (D )o f less than 4.1%.
TL;DR: In this article, the mechanical, piezoelectric and dielectric properties of PZT ceramics (Pb 0.98 M 0.02 [(Zr 0.535 Ti 0.465 ) 0.995 ]O 3, M=Er, Gd, Eu, Nd, La and Bi) have been studied.
Abstract: Mechanical, piezoelectric and dielectric properties of PZT ceramics (Pb 0.98 M 0.02 [(Zr 0.535 Ti 0.465 ) 0.995 ]O 3 , M=Er, Gd, Eu, Nd, La and Bi) have been studied. The fraction of A sites occupied by the different additives is estimated and is found to increase with the ionic radius of the additive ion. The density is high in Bi-, Gd- and Eu-PZT samples. Small amounts of the pyrochlore phase are present in Gd- and Eu-PZT. A maximum strength of 80–100 MPa and K IC of ∼1.5 MPa m 1/2 are obtained in Gd- and Eu-PZT. The R -curve behavior becomes more pronounced in Gd- and Eu-PZT, and it is observed that the strength and K IC increase with the slope of the K IC versus c 1/2 plot. Very good piezoelectric properties, i.e. d 33 of 410 PCN −1 , dielectric constant of 1005, κ p of 0.49 and the hydrophone figure of merit, d h g h , of 2760 are obtained for Nd-PZT. The piezoelectric properties in Bi-PZT are also higher than for the undoped composition, while for the Gd-PZT, these are slightly inferior. For all other compositions, the piezoelectric properties are not affected much.
TL;DR: In this article, the authors applied symmetric partial electrodes of different widths to lead zirconate titanate (PZT) plates to study the development of these cracks.
TL;DR: In this paper, improved dielectric properties of lead zirconate titanate (PZT) films deposited on a variety of foils using buffer layers are reported.
Abstract: Improved dielectric properties of lead zirconate titanate (PZT) films deposited on a variety of foils using buffer layers are reported. Foils include titanium, stainless steel, and nickel with LaNiO3(LNO) buffer layers which were prepared by sol–gel processing. High dielectric constant (330 for stainless steel, 420 for titanium, and 450 for nickel foils), low dielectric loss (<2.2% for titanium and 8% for stainless steel), symmetric ferroelectric C–V characteristics and P–E curves were obtained. The LNO layers are shown to provide an effective diffusion barrier for Ni and Cr and to restrict oxide layer formation (i.e., TiOx or NiOx) between the PZT film and the metallic foils during annealing in air.
TL;DR: In this article, the TMAH concentration and reaction time have a pronounced effect on the phase composition and morphology of the resultant powders, and the appearance of a fibrous intermediate phase, Zr-modified tetragonal PX-phase PbTiO 3 is observed at the early stage of the hydrothermal process.
TL;DR: In this paper, lead zirconate titanate (PZT)-based perovskites with common platinum (Pt) electrodes have been used for ferroelectric random access memories (FRAM).
Abstract: The development of lead zirconate titanate (PZT)-based capacitors has been a long time goal of ferroelectric random access memories (FRAM). However, PZT-based perovskites with common platinum (Pt) electrodes have suffered from a significant reduction of the remanent polarization (Pr) after a certain number of read/write cycles (electrical fatigue). We now report the development of fatigue-free lanthanum-modified PZT capacitors using common Pt electrodes. The capacitors fabricated at 580 °C by applying a PZT seed layer exhibited fatigue-free behavior up to 6.5×1010 switching cycles, a quite stable charge retention profile with time, and comparatively high Pr values, all of which assure their suitability for practical FRAM applications.
TL;DR: In this article, the effect of heating rate on the sintering behavior and the piezoelectric properties of lead zirconate titanate (PZT) ceramics was investigated.
Abstract: The effect of heating rate on the sintering behavior and the piezoelectric properties of lead zirconate titanate (PZT) ceramics was investigated. Two different types of PZT (pure and doped with Nb2O5) were sintered at 1150°C for 2 h with a wide range of heating rate (0.5°–100°C/min). The densification of pure PZT was improved significantly by increasing the heating rate. The improvement was attributed to the suppression of PbO volatilization and grain coarsening during heating. In contrast, the densification behavior of a PZT specimen doped with Nb2O5 was not much influenced by the heating rate. These densification behaviors affected the piezoelectric properties of the specimens. The piezoelectric properties of pure PZT were enhanced significantly by increasing the heating rate, while those of doped specimens were improved only moderately.
TL;DR: In this article, a fine fibrous structures of C60 with a diameter on the order of nanometers were discovered in a lead zirconate titanate sol ultrasonically mixed with a toluene solution.
Abstract: Fine fibrous structures of C60 with a diameter on the order of nanometers were discovered in a lead zirconate titanate sol ultrasonically mixed with a toluene solution of C60. By transmission electron microscopy observations, they were identified as single-crystalline fibers of C60 with submicrometer diameters, i.e., nanowhiskers of C60. The C60 nanowhiskers showed thin slablike TEM images, and the growth axis of the nanowhiskers was parallel to the 〈110〉 close-packed direction of a fcc crystal system of C60.
TL;DR: In this article, lead zirconate titanate (PZT) films were deposited on nesa silica glass substrates by spin coating using a Pb(NO3)2-Zr(OC3H7n)4-Ti(OC 3H7i)4 solution containing polyvinylpyrrolidone and acetylacetone.
Abstract: Lead zirconate titanate (PZT) films were deposited on nesa silica glass substrates by spin coating using a Pb(NO3)2–Zr(OC3H7n)4–Ti(OC3H7i)4 solution containing polyvinylpyrrolidone and acetylacetone. The coating solution had stable viscosity for over 1300 h at room temperature. Single-layer PZT films as thick as 0.75 μm could be obtained via single-step spin coating with successive gel film heat treatments at 80, 300, and 700 °C. The fired films were optically transparent and crack free, exhibiting P–E hysteresis loops with remanent polarization of 24.6±1.6 μC cm−2 and coercive field of 95.6±9.8 kV cm−1.
TL;DR: In this paper, lead zirconate titanate (PZT) and platinum (Pt) particulate composites were fabricated by power processing, and the electrical and mechanical properties of the PZT-Pt composite were measured as a function of the Pt volume fraction.
Abstract: As a model for composite materials of piezoelectric ceramic and metal, lead zirconate titanate (PZT) and platinum (Pt) particulate composites were fabricated by power processing. The electrical and mechanical properties of the PZT–Pt composites were measured as a function of the Pt volume fraction. The relative dielectric constants of the PZT–Pt composites increased markedly, while the piezoelectric constants and electromechanical coupling coefficients decreased with increasing Pt content. When the Pt volume fraction exceeded 30%, the PZT–Pt composite became electrically conductive because of percolation of the Pt particles. The Pt-dispersed PZT composites enhanced the mechanical properties, particularly the high fracture resistance, compared to the monolithic PZT ceramics.
TL;DR: In this article, the effect of polymer volume and properties and sintering temperature on microstructure of samples and on their physical properties has been investigated, and the differences between the microstructural aspect of samples prepared by different methods and their influence on the physical properties of the samples are presented.
Abstract: Piezoelectric porous lead zirconate titanate (PZT) ceramics prepared by different methods have been examined from a microstructural point of view. The effect of polymer volume and properties and sintering temperature on microstructure of samples and on their physical properties has been investigated. The wide range of pore volumes and pore size distributions was obtained by three different procedures: (a) reduction of the sintering temperature of the die pressed PZT samples; (b) use of a different forming technique like tape casting, starting from slurries with high volume of organic content; (c) addition of different volume concentrations of organic polymer to the PZT powder. It has been found that varying process parameters like quantity of polymer and sintering temperature changes both final porosity as well as pore size distribution, introducing dispersion in physical property values. The differences between the microstructural aspect of samples prepared by different methods and their influence on the physical properties of the samples are presented and discussed.
TL;DR: In this article, high performance electroactive materials were studied as the driver element for the “cymbal” flextensional transducer, and the influence of material properties, cymbal design, and drive signal on the displacement amplification factor was discussed.
Abstract: High performance electroactive materials were studied as the driver element for the “cymbal” flextensional transducer. The compositions included were commercially available Navy Type I and PKI552 lead zirconate titanate (PZT) piezoceramic, relaxor lead magnesium niobate-lead titanate (PMN-PT) ceramic, lead zinc niobate-lead titanate (PZN-PT) single crystal, and lead lanthanum stannate zirconate titanate (PLSnZT) ceramic with antiferroelectric to ferroelectric transitions. Displacement amplifications from 14× to 50× were found for various cymbal configurations. The influence of material properties, cymbal design, and drive signal on the displacement amplification factor is discussed.
TL;DR: In this paper, a new and simple method is described for the determination of the piezoelectric coefficients d33,f and e31,f for PZT films on silicon substrates.
Abstract: A new and simple method is described for the determination of the piezoelectric coefficients d33,f and e31,f for piezoelectric films deposited on substrates using a conventional point-loading `d33' or `Berlincourt' piezometer. An analytical mathematical model is developed which simulates the dynamical flexure of such films when a ring-supported sample is subject to central loading. Classical plate theory and elastic analysis are used to calculate the stresses in doped lead zirconate titanate (PZT) film for different radii of supporting rings, enabling both piezoelectric coefficients to be determined through a simple modification to the piezometer. The analytical model for the radial stresses has been evaluated in comparison with the results of finite element analysis and has shown a good correlation. The new measurement technique has been applied to both thick films of PZT and thin films of manganese-doped lead zirconate titanate (PMZT) on silicon substrates. The values of d33,f and e31,f obtained experimentally are found to be similar to those that have been determined by more elaborate methods.
TL;DR: In this article, the dry etching mechanism of lead zirconate titanate (PZT) films was studied in high density CF4 and Cl2/CF4 inductively coupled plasmas.
Abstract: The dry etching mechanism of lead zirconate titanate (PZT) films was studied in high density CF4 and Cl2/CF4 inductively coupled plasmas. The concentrations of atomic Cl and F as well as the flux and energy of bombarding ions were monitored as a function of etching parameters such as etching gas ratio, substrate bias voltage (Vs), induction coil power and process pressure. The compositions and chemical bonding states of etched PZT films were examined by X-ray photoelectron spectroscopy (XPS). The etching of PZT films in CF4-based plasma is chemically assisted sputter etching, and the dominant step of the overall etching process is either the formation or the removal of the etch by-products, depending on the etching conditions. The etching of PZT films in Cl2/CF4 mixed plasma is mainly dominated by the formation of metal chlorides which depends on the concentration of the atomic Cl and the bombarding ion energy. The PZT film shows a maximum etch rate in 90% Cl2/(Cl2+CF4) plasma where the concentration of atomic Cl is maximum. The etch selectivity of PZT to Pt is less than 1.3 in CF4-based plasma, where as more than 2 in Cl2/CF4 mixed plasma. The amount of sidewall residue is greatly reduced in Cl2/CF4 mixed plasma compared with in CF4 plasma. A more vertical etch profile of PZT films can be obtained by lowering the process pressure and increasing the substrate bias voltage.