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Lead zirconate titanate
About: Lead zirconate titanate is a research topic. Over the lifetime, 7141 publications have been published within this topic receiving 150878 citations.
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TL;DR: Rotations in three orthogonal directions have been observed by controlling the phase of the driving signal to the PZT electrodes, and a MDOF ultrasonic motor was successfully realized.
Abstract: This paper describes a new multi-degree-of-freedom (MDOF) ultrasonic motor that comprises few parts and is based on low-cost thick-film technology. Conventional ultrasonic motors using bulk lead zirconate titanate (PZT) or thin-film PZT layers are relatively expensive at the present time. Thick-film printed PZT technology provides the opportunity to reduce the costs of ultrasonic motors. To demonstrate the feasibility of this approach, an ultrasonic motor was fabricated from alumina using thick-film printed PZT actuators. The thick-film PZT and electrode layers were printed on a thin alumina plate, and a tiny cylinder was mounted at its center. This cylinder magnifies the lateral displacement of the stator, holds the spherical rotor, and transmits the driving force to the sphere. Three bending vibrations, B/sub 22/, B/sub 30/, B/sub 03/, of the plate were applied to rotate the sphere. Sufficient displacements for rotating the sphere were obtained near the resonance of B/sub 22/ by applying an excitation voltage of 200 V peak-to-peak via a three-phase drive circuit. Rotations in three orthogonal directions have been observed by controlling the phase of the driving signal to the PZT electrodes, and a MDOF ultrasonic motor was successfully realized.
85 citations
TL;DR: In this article, an interfacial adhesion mechanism in PZT-polymer composites can lead to a dielectric constant that is, remarkably, seven times greater than what is usually found.
Abstract: Ferroelectric ceramics (e.g., lead zirconate titanate, PZT) and polymers exhibit extraordinary dielectric and piezoelectric properties and processability, respectively. It is, however, difficult to retain the ideal dielectric constant (er) and piezoelectric coefficient (d33) in their composites. Here we show that an interfacial adhesion mechanism (afforded by the chelation technique) in PZT-polymer composites can lead to a dielectric constant that is, remarkably, seven times greater than what is usually found. At frequencies below 40 Hz, the dielectric constant of the composite is higher than in PZT alone (i.e., er > 1300), and this is the first achievement of the ceramic–polymer 0–3 composites as reported. Additionally, a super-high piezoelectric coefficient (d33 > 170) is also obtained owing to the interfacial mechanism. Our finding can lead to a novel way for preparing ceramic–polymer composites with an ultrahigh dielectric constant and ultrahigh piezoelectric coefficient, which are required in many modern electric systems and energy converters.
85 citations
TL;DR: In this article, a model is discussed which suggests that the origin of incommensuration is due to a competition between anti-ferroelectric and ferroelectric tendencies, and it is believed that the electrically induced strain is decoupled from the polarization due to AFE-FE switching by the field modulation of the incomensurately modulated polar structure.
Abstract: Tin-modified lead zirconate titanate ceramics, Pb(0.99)Nb0.02-[(Zr0.55Sn0.45)0.98Tiy]O3 (PZST 45/y/2), have been studied by hot-stage transmission electron microscopy (TEM), dielectric spectroscopy, Sawyer-Tower polarization (P—E) measurements, and electrically induced strain (e-E) techniques. The compositional range chosen for investigation was 0 < y < 0.09. Electron diffraction confirmed the existence of 1/x〈110〉 superlattice reflections in the previously designated antiferroelectric tetragonal state. For PZST 45/0/2, the room-temperature modulated structure was found to be commensurate with the lattice and isomorphous with the antiferroelectric orthorhombic phase of PbZrO3. With increasing Ti content, the modulation wavelength (λ) increased and became incommensurate. At high temperatures, λ was found to be incommensurate for all compositions. A model is discussed which suggests that the origin of incommensuration is due to a competition between anti-ferroelectric and ferroelectric tendencies. P—E studies revealed antiferroelectric-ferroelectric (AFE—FE) polarization curves which possessed no hysteresis in the incommensurate region, indicating a thermally reversible AFE—FE transformation. On cooling, strong hysteresis developed as the incommensurate structure became metastably locked. Investigations then revealed that the electrically induced strain associated with the AFE—FE transformation was not realized until field strengths were attained significantly above that required for polarization saturation. It is believed that the electrically induced strain is decoupled from the polarization due to AFE—FE switching by the field modulation of the incommensurately modulated polar structure.
85 citations
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.
85 citations
TL;DR: In this paper, the behavior of two sets of woven fiberglass/epoxy specimens, one with embedded and one with surface-mounted piezoelectric wafer transducers (lead zirconate titanate), were tested under axial tensile fatigue at high stress ratio, and the transducers were interrogated in pitch-catch mode at different stages of the specimens' life, while they were subjected to the mean test load (the testing machine is paused).
Abstract: The need to understand and monitor the integrity of structural components made of composite materials is becoming critical, due to an increase of the use of composites in aerospace, civil, wind energy, and transportation engineering. Off-the-shelf piezoelectric transducers embedded inside the composites or bonded onto the structure surface are a pos- sible solution for on-line structural health monitoring and non-destructive evaluation: they can be used to generate Lamb waves, which are able to detect damage. This article focuses on the behavior of two sets of woven fiberglass/epoxy specimens, one with embedded, one with surface-mounted piezoelectric wafer transducers (lead zirconate titanate). The specimens are tested under axial tensile fatigue at high stress ratio, and the transducers are interrogated in pitch-catch mode at different stages of the specimens' life, while they are subjected to the mean test load (the testing machine is paused). A novel signal processing technique based on wavelet thresholding/denoising and Gabor wavelet transform is discussed. This technique identifies changes in boundary conditions, loading/unloading prior to damage and during damage. It appears to correlate the contour area changes with the so-called characteristic damage state observed in the literature in composite laminates under tensile fatigue.
85 citations