Piezoelectric Crystal Research Articles

Hydrostatic piezoelectric parameters of lead-free 2–0–2 composites with two single-crystal components: Waterfall-like orientation dependences

A system of hydrostatic parameters is studied in novel 2–0–2 composites that contain two lead-free piezoelectric single-crystal components. The ferroelectric domain-engineered alkali niobate-tantalate-based single-crystal layer promotes large values of the piezoelectric coefficients [Formula: see text] and [Formula: see text], hydrostatic squared figure of merit [Formula: see text], and hydrostatic electromechanical coupling factor [Formula: see text] of the composite wherein the 0–3 Li2B4O7 single crystal/polyethylene layers are adjacent to the aforementioned single-crystal layer. Hereby, the role of the elastic anisotropy of the 0–3 layer is emphasized. An orientation effect concerned with rotations of the crystallographic axes of the piezoelectric Li2B4O7 single crystal in the 0–3 layer is first studied. It is shown that the orientation of the crystallographic axis [Formula: see text] of the Li2B4O7 single crystal in the polymer matrix strongly influences the piezoelectric properties and hydrostatic parameters of the composite. Examples of the so-called waterfall-like orientation dependences of the hydrostatic parameters are analyzed. The composite based on the domain-engineered [Lix([Formula: see text][Formula: see text]]([Formula: see text][Formula: see text]O3:Mn single crystal is of interest due to [Formula: see text][Formula: see text]mV[Formula: see text]m/N, [Formula: see text] Pa[Formula: see text], and [Formula: see text]–0.75 in the studied volume-fraction and orientation ranges, and these hydrostatic parameters are to be taken into account in the field of piezotechnical, hydroacoustic, and energy-harvesting applications.

Estimation of the output parameters of a numerical model of a cantilever-type piezoelectric generator with attached mass and active termination upon pulsed excitation

A simulation of a piezoelectric generator (PEG) of energy is given. A feature of this generator is the presence of two types of piezo elements: plate-type elements experiencing bending deformations and cylindrical-type elements experiencing compression deformations. The simulation in the finite element complex is presented. The results of the analysis of unsteady oscillations during vibrational pulsed excitation of the PEG base are presented. Variations in the time range of PEG loading are considered. The analysis of output power and operation of individual elements of the generator is given.

Water Molecule-Triggered Anisotropic Deformation of Carbon Nitride Nanoribbons Enabling Contactless Respiratory Inspection

The exploitation of the interaction between nanostructured matter and small molecules, such as H2O at interfaces via dynamic hydrogen bonding, is essentially the key for smart, responsive nanodevic...

Direct Acoustic Imaging Using a Piezoelectric Organic Light-Emitting Diode

Conventional ultrasonic imaging requires acoustic scanning over a target object using a piezoelectric transducer array, followed by signal processing to reconstruct the image. Here, we report a novel ultrasonic imaging device that can optically display an acoustic signal on the surface of a piezoelectric transducer. By fabricating an organic light-emitting diode (OLED) on top of a piezoelectric crystal (lead zirconate titanate, PZT), an acousto-optical piezoelectric OLED (p-OLED) transducer is realized, converting an acoustic wave profile directly to an optical image. Due to the integrated device architecture, the resulting p-OLED features a high acousto-optic conversion efficiency at the resonant ultrasound frequency, providing a piezoelectric field to drive the OLED. By incorporating an electrode array in the p-OLED, we demonstrate a novel tomographic ultrasound imaging device that is operated without a need for conventional signal processing.

Power Generation Using Piezoelectric Material

The energy crisis is the main issue of the world these days. The motto of the research work is to face the crisis. Nowadays the demand for electricity is increasing day by day, so the ultimate solution to solve this problem is to use renewable sources of energy. In this project, we are generating electricity using non-conventional techniques. In this project, when human walks surrounding, some force is applied on the surface of the piezo sheet, this force can be used to generate electricity. The piezoelectric crystal has crystalline structure & ability to convert mechanical stress into electrical energy.

Electro-mechanical coupling band gaps of a piezoelectric phononic crystal Timoshenko nanobeam with surface effects

Plane wave expansion (PWE) method is extended to calculate the band structures of a proposed piezoelectric phononic crystal (PC) nanobeam by applying surface elasticity and Timoshenko beam theories. The calculation method is derived and formulized in detail. Further, electrical voltage and external axial force are picked to study the effects of electro-mechanical coupling fields on band gaps, residual surface stress and material intrinsic length are chosen to research the influences of surface effects on band gaps, and ratio between lengths of PZT-4 and epoxy in a unit cell and height-width ratio are picked to investigate the effects of geometric parameters on band gaps. In addition, all the results are compared to those in Euler nanobeam with same parameters. All the results and further analysis demonstrate that the influence rules will play an active role in design process and active control of nano electro-mechanical system based on piezoelectric PC nanobeam.

Growth of high quality Li2B4O7 single crystals: Core formation revisited by using electric force microscopy

Lithium tetraborate is a well known piezoelectric crystal with a wide variety of applications in the field of Surface Acoustic Wave (SAW) devices and also as a strong candidate for the fabrication of high performance personal dosimetry systems. However, it is well known the tendency of this crystal to form a central core which greatly affects to its physical properties. Although this issue has been studied four decades, it seems that some issues regarding to the core formation in lithium tetraborate crystals still remain to be understood. In this work, the effect of the thermal gradient and some other parameters like rotation speed and growth rate on the core formation has been analysed in order to ascertain the best growth conditions to obtain high quality single Li2B4O7 crystals. Several lithium tetraborate crystals have been grown by standard Czochralski technique and the formation and structural and electrical properties of the core region have been analysed by using Electric Force Microscopy (EFM).

Bulk growth, structural and electrical properties of (1-x)Na0.5Bi0.5TiO3-xBaTiO3 piezoelectric single crystals by top seeded solution growth method

The solid solution of 0.94(Na0.5Bi0.5)TiO3-0.06BaTiO3 NBBT94/06 is a promising material to replace Lead (Pb) based piezoelectric materials. The bulk NBBT 94/06 single crystal was successfully grown by the top-seeded solution growth (TSSG) method. Lead-free piezoelectric NBBT single crystals with a composition across the morphotropic phase boundary (MPB) have been grown by the TSSG method. NBBT 94/06 single crystal, encompassing the rhombohedral to largely monoclinic phase covering the MPB region was grown by the TSSG method. The crystal structure and its electrical properties were investigated. The Laue diffraction pattern confirms that the grown crystal is a single crystal. Rietveld refinement studies disclose the existence of a phase boundary between Monoclinic (Cc) and Rhombohedral (R3c) phases near the MPB. The depolarization temperature (Td), piezoelectric coefficient (d33) and ferroelectric properties were enhanced at MPB.

Patterns of Whisker Movement Activity in the States of Sleep and Waking in Neonatal Rats

The aims of the present work was to describe primitive whisker movements in neonatal Wistar rats (postnatal days 4–7) in the states of sleep and waking and to study correlations between whisker movements and body movements. Whisker movements were recorded by high-speed video recording and the animals’ behavioral state was determined by recording electromyographic activity of the cervical muscles and simultaneous recording of limb movements using piezo elements. During active sleep, movements consisted mostly of short-term whisker movements, and a significant proportion of these movements arose simultaneously with short-term bursts of activity in the cervical muscles and transient myoclonic twitches of the animal’s body. During periods of waking, movements were mostly complex long-lasting whisker movements, which were accompanied by long-term increases in cervical muscle tone and complex body and limb movements. Both types of whisker movement occurred mainly in the rostral and caudal directions, and the amplitude of movements during waking was only slightly greater than the amplitude of whisker movements during sleep. The data obtained here provide evidence that the temporal organization of whisker movement activity in neonatal rats is significantly different in the states of sleep and waking and that whisker movements in both behavioral states showed strong correlations with the animal’s body movements. It is suggested that generalized primitive whisker and body movements in neonatal rats are due to the activity of a single central pattern generator both in the state of active sleep and in the state of waking.

Development of variable preload system for machine tool spindle using giant magnetostrictive material Terfenol-D actuator

Applying a bearing preload of machine tool spindle produces positive effects, including increased stiffness, rotation noise reduction, increase in shaft precision, position adjustment during operation, and prevention of rolling element resonance and rotating slip, along with a significant extension of the bearing lifespan. A variable preload technique is a method that improves the bearing performance by appropriately varying the preload applied to the bearing according to the spindle rotation speed and machining condition. In this study, a novel variable preload method utilizing a Terfenol-D actuator has greater power and more displacement and force than those of other transducer materials such as piezo elements or nickel alloys. Terfenol-D has greater power and more displacement and more force. A prototype of a spindle for the variable preload system using Terfenol-D was fabricated, and the axial force and displacement of the bearing were measured during a running experiment. In order to assess whether the proposed variable preload device can effectively apply preloading to the bearing, a comparative analysis was conducted between the theoretical and empirically obtained values of the bearing axial direction displacement. Through the comparative analysis, the real applicability of the proposed structure was confirmed.

Energy production through the contact of piezoelectric crystals, in a teaching institution in the City of Manaus- Amazonas

Electric energy is responsible for several factors that keep us active and in communication with the rest of the world, where they present various ways of producing electric energy, including renewable energies. The most used type of energy is linked to non-renewable sources, causing numerous environmental impacts, other types can be described for power generation considering less consumption, greater stability, lower cost as in the case of piezoelectricity, which is still little used. However, it proves to be a highly efficient alternative, given the generation of energy by means of piezoelectric crystals, mechanically stimulated by pressure (scalar magnitude of mechanical condition, presented in physics), which proves to be an advantage given the types of production power.

Coupled Piezoelectric Phononic Crystal for Adaptive Broadband Wave Attenuation by Destructive Interference

Abstract In this paper, we report a piezoelectric phononic crystal plate featuring broadband wave attenuation. In the piezoelectric phononic crystal system, the transmitted elastic wave is attenuated owing to destructive interference by taking advantages of phase difference. The proposed concept is applied to a piezoelectric phononic crystal plate synthesized by functional dual-lane units that yields phase difference. Whereas, the piezoelectric unit-cells are connected negative capacitance shunt circuits individually. Our analysis shows that the coupled phononic crystal has a strong broadband low-frequency wave attenuation capability. The bandwidth of 10 dB wave attenuation is broadened by 34 times in the vicinity of 5 kHz comparing to that of a local resonance metamaterial under the same mechanical configuration. Moreover, the frequency range of wave attenuation of the proposed system can be online adjusted through the modification of the external shunt circuits.

Acoustic wave propagation in anisotropic media with applications to piezoelectric materials

ABSTRACT In this paper, we analyze acoustic wave propagation in anisotropic fluids and solids. By formulating the acoustic system as an evolution equation over a Hilbert space, we obtain global in time solutions when the associated material parameters are bounded and measurable. In particular, we prove well-posedness of a Cauchy problem for wave propagation in piezoelectric crystals. We then provide a stability analysis of these solutions not assuming positive definiteness of the stress–strain tensor or the piezoelectric stress tensor. Finally we prove continuous dependence on initial data, allowing the piezoelectric tensor to depend on space and time, provided solutions belong to an appropriate function space.

Growth and electrical properties of self-flux method grown (1−x)Bi1/2Na1/2TiO3−xBaTiO3 single crystals across the morphotropic phase boundary

The ferroelectric solid solution 0.94(Bi1/2Na1/2)TiO3–0.06BaTiO3 (BNBT) is a promising material to substitute the environmentally undesired Pb-based ferroelectrics. Lead-free piezoelectric BNBT bulk size single crystals with a composition across the morphotropic phase boundary (MPB) have been successfully grown by the self-flux method. Powder X-ray diffraction (PXRD) pattern confirms the perovskite structure of the synthesized BNBT crystals. The lattice strain is calculated as 1.7 × 10−2 using Williamson–Hall equation from PXRD. The elemental composition of the BNBT single crystals grown with different compositions is confirmed by X-ray fluorescence, covering the rhombohedral to tetragonal region and encompassing the MPB. The presence of a phase boundary between rhombohedral and tetragonal phases near MPB results in electrical behavior enhancement. The dielectric, ferroelectric, and piezoelectric properties along the pseudocubic direction have been measured. Dielectric permittivity gives diffuseness of BNBT crystals and it confirms the relaxor-type behavior. AC conductivity gave the activation energy as 0.46 eV.

An innovative idea for low cost Braille e-reader

Background/Objectives: The aim of this study was to implement the rotating cubes for designing the Braillerefreshable display. The rotating cube Braille display has many benefits i.e., compact size, low cost etc. Methods/Statistical analysis: refreshable Braille display is an electro mechanical device which forms Braille charactersby raising pins through holes on flat surface. The raising of such pins is accomplished by complex and costly systems like solenoids or piezo-electric crystals or EAP (Electro Active Polimer). We developed the prototype of e-book reader, which is a low cost electro mechanical system aimed at assisting visually impaired to access the e-books. Findings: Many design concepts were proposed earlier and prototypes were built, and were tested successfully in thepast by using three simple rotating cubes. The main parameters like dot spacing, overall dimension, touching force and operating voltage obtained are discussed. Dot spacing 2.5 [mm] with reference to International standard has been maintained. Regarding overall dimension, the display unit is designed to have dimension of 120mm width to 150mm height adhering to NLS standard of Braille dot spacing, and the tactile surface will feature 13 lines with 14 characters per line. The touching force of 0.32N and operating voltage below 25 V was obtained and used. Novelty/Applications: The Solenoid is used for positioning the faces of individual cubes, which can be arranged in different positions thereby forming all Braille characters. The high power consumption which remained the major head ache in solenoid electromagnetic actuator models was a major challenge we faced initially, which we overcame with our unique innovative design combining cubes that can rotate to form Braille dots and electromagnetic actuator which can be positioned at various places to run this cubes. So Keeping Occam\'s Razor Principle in mind, we went ahead to design a multicell/multi-line electronic refreshable Braille display as a technology demonstrator by using three simple rotating cubes. Keywords: Braille cell; Rotating cubes; Actuators; Refreshable Braille displays

High-voltage transformer

An original electric transformer was developed. The transformer generates a high AC voltage from a low-voltage AC. The input AC voltage generates an axial vibration in the electrodynamic actuator. The axial vibration is transmitted to piezoelectric crystals which are polarized in the axial direction and generates the output voltage. The transformer works at an axial mechanical resonance frequency of the system. Equations that describe the behaviour of the device were found. These equations were validated with measured data. The transformation ratio was obtained from these. Very high transformation ratio can reach this device, indicating the theoretical model. The proposed system is easy to build of reduced dimensions and low cost. Due to the high energy density of piezoelectric materials, high transformation ratio, the high electromechanical coupling factors and the high-quality factor of the mechanical resonance (low damping), it is lighter and more efficient than wire-wound transformers for high transformation ratio. This transformer could be used in devices, such as X‐ray machines, electron microscope, solid-state propulsion system, Ion thruster, small particle accelerator and accelerator-driven systems.

Flexural Deflection Prediction of Piezo-Composite Unimorph Actuator Using Material Orthotropy and Nonlinearity of Piezoelectric Material Layer

Layered piezo-composite unimorph actuators have been studied by many research teams to provide active vibration control of thin-walled aerospace structures, control the shapes of aircraft wing airfoils, and control the fins of small missiles, because they require less space and provide better frequency responses than conventional electro-magnetic motor actuator systems. However, due to the limited actuation strains of conventional piezo-composite unimorph actuators with poly-crystalline piezoelectric ceramic layers, they have not been implemented effectively as actuators for small aerospace vehicles. In this study, a lightweight piezo-composite unimorph actuator (LIPCA-S2) was manufactured and analyzed to predict its flexural actuation displacement. It was found that the actuated tip displacement of a piezo-composite cantilever could be predicted accurately using the proposed prediction model based on the nonlinear properties of the piezoelectric strain coefficient and elastic modulus of a piezoelectric single crystal.

Wavelength transduction from a 3D microwave cavity to telecom using piezoelectric optomechanical crystals.

Microwave-to-optical transduction has received a great deal of interest from the cavity optomechanics community as a landmark application for electro-optomechanical systems. In this Letter, we demonstrate a novel transducer that combines high-frequency mechanical motion and a microwave cavity for the first time. The system consists of a 3D microwave cavity and a gallium arsenide optomechanical crystal, which has been placed in the microwave electric field maximum. This allows the microwave cavity to actuate the gigahertz-frequency mechanical breathing mode in the optomechanical crystal through the piezoelectric effect, which is then read out using a telecom optical mode. The gallium arsenide optomechanical crystal is a good candidate for low-noise microwave-to-telecom transduction, as it has been previously cooled to the mechanical ground state in a dilution refrigerator. Moreover, the 3D microwave cavity architecture can naturally be extended to couple to superconducting qubits and to create hybrid quantum systems.

Study on the vibration attenuation property of one finite and hybrid piezoelectric phononic crystal beam

In this paper, a theoretical method is proposed to effectively improve the vibration attenuation characteristics of a finite hybrid piezoelectric phononic crystal (PC) beam utilizing the non-uniform distribution of shunting circuits. Considering the damping of resonators, the vibration transmissibility method (TM) for the finite electromechanical system is derived based on the Timoshenko beam theory. Numerical results are validated by the finite element method (FEM). Subsequently, a comprehensive study is conducted to investigate the influences of the structural and electrical parameters on the vibration attenuation property of the uniform PC. Furthermore, the organized disorder of the shunting circuits is introduced into the system. Combining with various types of non-uniform circuit configurations, the variation of the vibration attenuation is also examined. It is demonstrated that the hybrid PCs offer more tunable mechanisms to design target band-gaps, compared with the purely mechanical and piezoelectric PCs. The low-frequency vibration reduction over a broadband range could be achieved through the selective coupling ways of the mechanical local resonant band-gap (LRG), electromechanical LRG and Bragg band-gap (BG). It is expected to enhance the vibration attenuation and availability of hybrid PCs using the suitable distribution of shunting circuits in practice.

Temperature dependence of mode coupling effect in piezoelectric vibrator made of [001]c-poled Mn-doped 0.24PIN–0.46PMN–0.30PT ternary single crystals with high electromechanical coupling factor**Project supported by the Basic Scientific Research Foundation of College and University in Heilongjiang Province, China (Grant No. 2018QNL-16), the Guiding Science and Technology Project of Daqing City (GSTPDQ), China (Grant No. zd-2019-03), and the National Natural Science Foundation

The influence of temperature on mode coupling effect in piezoelectric vibrators remains unclear. In this work, we discuss the influence of temperature on two-dimensional (2D) mode coupling effect and electromechanical coupling coefficient of cylindrical [001]c-poled Mn-doped 0.24PIN–0.46PMN–0.30PT piezoelectric single-crystal vibrator with an arbitrary configuration ratio. The electromechanical coupling coefficient kt decreases with temperature increasing, whereas k33 is largely invariant in a temperature range of 25 °C–55 °C. With the increase of temperature, the shift in the ‘mode dividing point’ increases the scale of the poling direction of the piezoelectric vibrator. The temperature has little effect on coupling constant Γ. At a given temperature, the coupling constant Γ of the cylindrical vibrator is slightly greater than that of the rectangular vibrator. When the temperature changes, the applicability index (M) values of the two piezoelectric vibrators are close to 1, indicating that the coupling theory can be applied to piezoelectric vibrators made of late-model piezoelectric single crystals.