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The dispersion and attenuation traits of Love-type waves propagating through a porous piezoelectric stratum imperfectly bonded to an anisotropic superficial stratum and a piezoelectric substratum have been irradiated through this analytical framework. With the aid of fundamental equations of motion and non-vanishing field equations, the electrical as well as mechanical displacements along with the constituents of electric potential have been obtained simultaneously. Applying stress free condition at the uppermost surface of the anisotropic stratum together with electro-mechanical boundary as well as continuity conditions at the common imperfect interfaces of the uppermost and intermediate strata as well as the intermediate stratum and piezoelectric substratum, the compact form of secular equation for the considered geometrical structure has been obtained. For better comprehension of the influence of the presumed parameters on the phase and attenuation phenomena of Love-type waves through the stratified Earth's structure with perfect and imperfect interfaces, a comparative graphical analysis has been accomplished by taking data corresponding to four different naturally occurring anisotropic rock samples namely, crystalline rock, North Sea sandstone, dry Vosges sandstone and saturated Lavoux limestone. [ABSTRACT FROM AUTHOR]

The work discussed is developing a self-sustainable low-power remote multi-sensing and data logging system for traffic sensing. The system is powered by the energy harvested using a stacked PZT (Lead zirconate titanate) transducer from the mechanical vibration from the vehicles passing over roads. The system is capable of multi-sensing functionality, logging the sensor data, and wirelessly transferring sensory data to an end-user device. Various power management techniques and engineering applications were made to achieve low power operation of the system while maintaining the full functionality and the accuracy of the sensor data. The energy harvester used is a custom-designed and fabricated stacked piezoelectric transducer optimized for maximum energy harvesting from the mechanical vibration from roadway traffic. A custom-built AC to DC converter is used to convert the harvested energy into useable electrical power. The system was tested under various experimental setups yielding satisfactory data accuracy while operating at low power. The system also successfully transferred sensor data remotely. All these features make the system self-sustainable and suitable for remote sensing applications without a conventional power source. [ABSTRACT FROM AUTHOR]

Temperature dependences of dielectric permittivity ϵ33, piezoelectric constant d36and elastic compliance S66of K1-x(NH4)xH2PO4ferro – antiferroelectric (FE - AFE) mixed crystals have been studied within temperature range 30 – 300 К. It was found a considerable contribution of the strain component x6to polarization P3near the FE transition temperature due to piezoelectric effect. Piezoelectric contribution to dielectric response in the vicinity AFE phase transition is weaker. It leads, in particular, to difference in the both shapes and positions of ϵ33and S66anomalies for K0,25(NH4)0,75H2PO4single crystal near the transition temperature. [ABSTRACT FROM PUBLISHER]

Lead-free 0.98(Na0.5K0.5)NbO3-0.02Ba(Zr0.52Ti0.48)O3ceramics modified with ZnO additive were fabricated by a conventional mixed oxide method. The ceramics were sintered at 1080°C for 4h. Gradual changes in piezoelectric and dielectric properties were observed with increasing ZnO content. Relative density increases after the addition of ZnO, reaching a large value of about 95% after the addition of 1.0 mol% ZnO. Curie temperature (Tc) slightly decreases with increasing ZnO content. Dielectric constant (4118), piezoelectric constant (d33= 231 ρC/N) and electromechanical coupling factor (kp= 0.45) have slight increases after the addition of ZnO due to the improvement in the densification of the ceramics. [ABSTRACT FROM AUTHOR]

Abstract: Lead-free (1− x)(Na0.53K0.404Li0.066)Nb0.92Sb0.08O3 + xCaAl2O4 (NKLNS–xCA) ceramics were prepared by the conventional mixed oxide method. The effects of the addition of CaAl2O4 on the phase transitions and electrical properties of the KNN-based ceramics were studied and the temperature stability of their piezoelectric and electromechanical properties was also discussed. It is found that 1.5mol% CaAl2O4 doped NKLNS ceramic exhibits stable piezoelectric and electromechanical properties in −40 to 60°C due to the extended polymorphic phase transition region induced by the B-site composition fluctuation. The piezoelectric constant d 33, dielectric loss tanδ, and electromechanical coupling factor k p of the NKLNS–0.0150CA ceramic are found to be 254 pC/N, 3.5%, and 45%, respectively, demonstrating that the NKLNS–0.0150CA ceramic is a very promising lead-free piezoelectric material for practical applications. [Copyright &y& Elsevier]

The alkaline niobate-based perovskite ceramics (Li,Na,K)(Nb,Ta,Sb)O3has been regarded as a new candidate of lead-free piezoelectric materials due to its excellent piezoelectric properties. In this study, Li0.02(Na0.55K0.45)0.98(Nb0.77Ta0.18Sb0.05)O3(abbreviated as LNKNTS) piezoelectric ceramics were fabricated by a conventional solid-state reaction method at various calcinations temperature and then, their dielectric and piezoelectric properties were investigated. At the calcinations temperature of 870°C and sintering temperature of 1140°C, the optimum values of density = 4.736g/cm3, kp = 0.423, Qm= 65, ϵr= 1545 and d33= 256 pC/N, were obtained, respectively. Taking into consideration above physical properties, it is considered that this composition is applicable to lead-free haptic piezoelectric actuators. [ABSTRACT FROM AUTHOR]

In order to develop lead-free composition ceramics for piezoelectric actuator, sensor, and transformer applications, (1-x)[Li0.04(Na0.54K0.46)]0.96(Nb0.84Ta0.10Sb0.06)O3 + x(Bi0.5Na0.5)TiO3 (x = 0∼2 mol%) composition ceramics were fabricated by a conventional sintering technique. The influences of (Bi0.5Na0.5)TiO3(abbreviated as BNT) on the microstructure, the dielectric, ferroelectric and piezoelectric properties of the ceramics were investigated. The crystal structure of specimens with x = 0 mol% exhibited an orthorhombic structure. However, at the compositions more than 0.5 mol%, the crystal structure showed tetragonal structure. The temperature dependence of dielectric constant showed that Curie temperature decreased with the increase of BNT substitution content. At room temperature, the ceramics substituted with 1 mol% BNT had a piezoelectric constant d33 = 222.6 pC/N, electromechanical coupling factor kp = 0.36, mechanical quality factor Qm = 78 and dielectric constant ϵr = 1570, respectively. [ABSTRACT FROM PUBLISHER]

ZnO nanorod arrays were grown on Zn substrates by an inexpensive and facile hydrothermal reaction at low temperature of 95°C. 0.1 M ZnCl2 was used as a precursor was dissolved in 100 ml of deionized water, and 2ml ammonia solution (25%) was added to the solution, it enable easily obtained arrayed ZnO nanorods. Morphology and microstructure of the ZnO nanorods was characterized. Precision impedance analyzer and quasi-static d33 measurer were employed to analyze the micro-area piezoelectric property. The resonant frequency and the piezoelectric constant of ZnO nanorod arrays are 1.09 MHz and 17 pm/V, respectively. [ABSTRACT FROM AUTHOR]

BaTiO3 ceramics with different grain size from 0.56 to 120 μm were prepared by the conventional solid state processing and two-stage sintering method using ultrafine BaTiO3 powders prepared by a sol-gel method. Dielectric, ferroelectric and piezoelectric properties of BaTiO3 ceramics with different grain size were investigated. The grain size effect of BaTiO3 ceramics on dielectric appeared clearly. The coercive field showed a maximum value of 7.14 kV/cm at the grain size of 1.1 μm and piezoelectric constant d33 showed a maximum value of 204 pC/N at 8.9 μm. The remanent polarization of BaTiO3 ceramics increased with the increasing of the grain size. [ABSTRACT FROM AUTHOR]

Abstract: The polycrystalline sample of Na1/2Dy1/2TiO3 ceramic was prepared by a standard high-temperature solid-state reaction technique. X-ray structural analysis confirmed the formation of single-phase (with minor secondary phase) compound in the orthorhombic (distorted tetragonal) crystal system at room temperature. Study of surface morphology by scanning electron microscope exhibits uniform distribution of rectangular/cubical grains with less voids. The elemental composition of the prepared compound was confirmed by energy dispersive X-ray spectroscopy microanalysis. Detailed studies of dielectric properties exhibit a dielectric anomaly at 94°C suggesting a possible ferroelectric–paraelectric phase transition in the compound. The activation energy (E a), calculated from the temperature dependence of ac conductivity plot, was found to be small (∼0.1eV) in low temperature and large (∼0.5eV) in high temperature region. [Copyright &y& Elsevier]

• Enhanced d 33 and T d were simultaneously achieved in 1.0 mol% Fe-doped NBT-6BT ceramics. • The enhancement is attributed to the stabilization of ferroelectric order, induced by the enhanced lattice distortion. • Fe-doping is an effective way to optimize the thermal stability and piezoelectric properties of NBT-based ceramics. The low depolarization temperature has hindered implementation of (Na 1/2 Bi 1/2)TiO 3 (NBT)-based lead-free piezoceramics in practical application, in particular, in high temperature environment. In this work, the impact of Fe modification on the microstructure, depolarization temperature, ferroelectric and piezoelectric properties of 0.94(Na 1/2 Bi 1/2)TiO 3 -0.06BaTiO 3 (NBT-6BT) lead-free ceramics were studied. The results illustrates that the piezoelectric constant and depolarization temperature can be significantly tuned by Fe doping, and more importantly, both can be simultaneously enhanced. Compared to the undoped material, the room-temperature piezoelectric constant of NBT-6BT with 1.0 mol% Fe doping increases from 133 pC/N to 164 pC/N, and the depolarization temperature increases from 106 °C to 125 °C. These observations are mainly attributed to the stabilization of ferroelectric order, induced by the enhanced lattice distortion. [ABSTRACT FROM AUTHOR]

In this study, lead-free 0.95(K0.5Na0.5)NbO3-0.05Li(Sb1 - xNbx)O3 system ceramics were fabricated according to the amount of Nb substitution for Sb site of LiSbO3 ceramics and their dielectric and piezoelectric characteristics were investigated. With increasing the amount of Nb substitution, electromechanical coupling factor (kp), density and piezoelectric constant (d33) increased up to 1mol% Nb and decreased above 1mol% Nb. With increasing the amount of Nb substitution, dielectric constant linearly decreased and Curie temperature increased. At the 1mol% Nb substitution composition ceramics sintered at 1040°C, electromechanical coupling factor (kp), density, dielectric constant (εr), piezoelectric constant (d33) and Curie temperature (Tc) showed the optimal value of 0.41, 4.35 g/cm3, 789, 206 pC/N and 395°C, respectively for piezoelectric device application. [ABSTRACT FROM AUTHOR]

The piezoelectric properties of PMN-PT ceramics with compositions near a morphotropic phase boundary were investigated under pressures p upto 150 MPa. The resonance and antiresonance frequency characteristics of impedance and phase in the k31 mode in the tetragonal phase for PMNT (67/33) and in the rhombohedral one for PMNT (69/31) ceramics were observed under various pressures. The resonance frequency fr remains almost constant and antiresonance one fa tends to increase with increasing p. The electromechanical coupling coefficient k31 in the k31 mode increases and the electromechanical quality factor Q decreases with increasing p. The decrease in Q with p is due to ferroelectric domain wall motions. The relative permittivity εr increases with increasing p. Such an increase in both k and εr dependent on p seems to be related to the decrease in ferroelectric domain size. [ABSTRACT FROM AUTHOR]

A new composite with special piezoelectric property was prepared by using lead magnesio-niobate piezoelectric ceram powders (PMN) as dispersing phase in acrylonitrile butadiene rubber (NBR) matrix. The dielectric and piezoelectric properties of the composite were studied. The result shows that the particle size of 80% of PMN ceram powders was 0.5-2 µm. The piezoelectric constant (d33) of the composite increased with increasing volume fraction of PMN, and the max piezoelectric constant is 33 when the PMN volume fraction is 85%. Appropriate delay of polarizing time with increasing polarizing voltage could be helpful to improve the d33 value. The optional polarizing condition is 25 min, 7-8 kv/mm, and 80°C. The dielectric constant increased with the increasing of the PMN volume fraction. Polarized time, polarized voltage, and polarized temperature have no effect on the dielectric constant. [ABSTRACT FROM AUTHOR]

The variation amount of TiO2 at 1, 3 and 5 mol% was added into 0.93(Bi0.5Na0.5)TiO3-0.07Ba(Ti0.95Zr0.05)O3, (BNT-7BZT) powder. The affect of excess TiO2 on ferroelectric properties of BNT-7BZT ceramics were studied. It was found that piezoelectric and dielectric constants as well as dissipation factor largely drop with an increase of TiO2 contents. However, TiO2 excess can stabilize the curie temperature and give a first phase transition temperature constantly at 125°C with TiO2 more than 1 mol%. [ABSTRACT FROM AUTHOR]

The morphotropic phase boundary of bismuth sodium titanate (BNT) and barium zirconate titanate (BZT) ceramics were study. In the case of (1-x)BNT-xBZT where x = 0.06 to 0.12 mol. The solid solution ceramics which have the combine phases between rhombohedral and tetragonal are obtained at x = 0.06 to 0.11 mol. The maximum of piezoelectric and dielectric constants are obtained for 0.93BNT-0.07BZT ceramics at 161 pC/N and 1839, respectively. This may be indicated that this composition is nearly existed of MPB region. [ABSTRACT FROM AUTHOR]

Abstract: In this study, ZnO thin films were fabricated using the rf magnetron sputtering method and their piezoelectrical and optical characteristics were investigated for various substrate temperatures. The ZnO thin film has the largest crystallization orientation for the (002) peak and the smallest FWHM value of 0.56° at a substrate temperature of 200°C. The surface morphology shows a relatively dense surface structure at 200°C compared to the other substrate temperatures. The surface roughness shows the smallest of 1.6nm at a substrate temperature of 200°C. The piezoelectric constant of the ZnO thin film measured using the pneumatic loading method (PLM) has a maximum value of 11.9pC/N at a substrate temperature of 200°C. The transmittance of the ZnO thin film measured using spectrophotometry with various substrate temperatures ranged from 75 to 93% in the visible light region. By fitting the refractive index from the transmittance to the Sellmeir dispersion relation, we can predict the refractive index of the ZnO thin film according to the wavelength. In the visible light range, the refraction index of the ZnO thin film deposited at a substrate temperature of 200°C is the range of 1.88–2.08. [Copyright &y& Elsevier]

Abstract: Highly c-axis-oriented aluminum nitride (AlN) thin films have been prepared on titanium (Ti) bottom electrodes by using AlN interlayers. The AlN interlayers were deposited between Ti electrodes and silicon (Si) substrates, such as AlN/Ti/AlN/Si. The crystallinity and crystal orientation of the AlN films and Ti electrodes strongly depended on the thickness of the AlN interlayers. Although the sputtering conditions were the same, the X-ray diffraction intensity of AlN (0002) and Ti (0002) planes drastically increased, and the full-width at half-maximum (FWHM) of the X-ray rocking curves decreased from 5.1° to 2.6° and from 3.3° to 2.0°, respectively. Furthermore, the piezoelectric constant d 33 of the AlN films was significantly improved from −0.2 to −4.5 pC/N. [Copyright &y& Elsevier]

The article reports on the high accuracy and high sensitivity measurements of the electrooptic effect in undoped and MgO-Doped LiNbO3 crystals. The fundamental and third harmonic components from photo-detection signals of the parallel Nico optics including the LN crystal driven by minimal sinusoidal voltage. Anti-reflection films must be coated on the end faces of the crystal for highly accurate measurements is indicated.

In order to develop a diamond probe with a piezoelectric sensor and actuator for atomic force microscope (AFM), we fabricated lead zirconate titanate (PZT) thin film on a diamond thin film substrate and examined its piezoelectric properties. The PZT thin film was sputtered at room temperature and then annealed to obtain a perovskite structure. After rapid thermal annealing at temperature ramp rate of more than 10 °C/s and at temperatures of more than 500 °C in a nitrogen (N2) ambient, the PZT thin film fabricated on flat Si substrates showed high piezoelectric constant, d31, of about -90 pC/N, as well as in an oxygen (O2) ambient. On diamond thin film substrates, the value of piezoelectric constant was as low as about -20 pC/N due to rough surface of the diamond film. After a poling treatment, however, its piezoelectric constant improved to about -65 pC/N. For realization of a PZT sensor and actuator on a diamond cantilever, the PZT thin film was also successfully patterned by reactive ion etching (RIE) in sulfur hexafluoride (SF6) plasma using a platinum (Pt) upper electrode layer as an etching mask without any damage on the diamond layer. Based on the fabrication and patterning of PZT thin film together with microfabrication techniques of diamond film formed by chemical vapor deposition (CVD), we demonstrate the diamond AFM probe of 150 μm in length, 50 μm in width, and 5 μm in thickness with a PZT sensor and actuator of 1 μm in thickness. The resolution of image sensing and actuation force were estimated to be about 0.4 nm at a resolution of charge measurement of 1×10-15 C, and 17 μN at an applied voltage of 8 V, respectively. [Copyright &y& Elsevier]

Electrical aging and mechanical fracture behavior of 0.2(PbMg1/3Nb2/3O3)–0.8(PbZr0.475Ti0.525O3) multilayer ceramic actuators have been investigated by applying both bipolar and unipolar voltages for unpoled and poled actuator, respectively. After 8.7×107 cycles of 2 kV/mm bipolar voltage, unpoled multilayer ceramic actuator had distorted shape of P–E hysteresis loops. Effective electromechanical coupling coefficient keff of poled actuator was calculated by considering resonant frequency and anti-resonant frequency. Pseudo-peizoelectric constant, d33, was also estimated through the strain versus electric field characteristics. From the SEM analysis, crack growth of multilayer ceramic actuator was clearly observed along the boundary between electrode and inactive region. The main reason for destruction of 0.2(PbMg1/3Nb2/3O3)–0.8(PbZr0.475Ti0.525O3) multilayer ceramic actuators was mechanical tensile stress coming from both actuation of, d33, mode and motion due to Poisson ratio. [Copyright &y& Elsevier]

Composition dependence of room temperature piezoelectric constant d33 and dielectric constant tunability was investigated in the 〈001〉-poled single crystals of (1−x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 with x varying from 0.24 to 0.38. Temperature, frequency and composition dependence of the dielectric constant in the unpoled crystals shows that the critical composition for the relaxor state lies in the 0.69Pb(Mg1/3Nb2/3)O3–0.31PbTiO3 crystal. It has also the largest piezoelectric constant d33 of 2210 pC/N and highest dielectric constant tunability of 40.6% (at a dc bias of 1000 V/mm). The experiment results validate the prediction that the relaxor-based materials with the critical composition for the relaxor state will have the highest piezoelectric susceptibility. [Copyright &y& Elsevier]

We built a prototype ultrasonic transducer that transmits the fundamental wave and detects nonlinear harmonic waves generated in a target material. This transducer is constructed from a piezoelectric oscillator ring that is only used for transmission at the resonance frequency of f0 and a piezoelectric oscillator disk that is only used for reception at the resonance frequency of 2f0. The two oscillators are arranged in the same housing on the same axis and the same plane, but are separated. By optimally combining the material constants of the piezoelectric oscillators and optimizing the combination of the resonance sharpness Q, we found that the second harmonic signal could be detected with high selectivity and high reception sensitivity. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(1): 27–35, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10030 [ABSTRACT FROM AUTHOR]

In order to develop a diamond atomic force microscopy (AFM) probe with a piezoelectric sensor and actuator, we fabricated piezoelectric zinc oxide (ZnO) thin film and measured its piezoelectric constant. First, we developed a simple measurement method for the piezoelectric constant of the thin film, d31. This was based on the free vibration theory of cantilever beams. The values of d31 were determined by measuring an electric charge induced in the piezoelectric thin film on the vibrating cantilever beam and its displacement. Using this method, we evaluated d31 for ZnO thin film sputtered at various substrate temperatures. The ZnO thin film deposited at temperatures of less than 350 °C was highly c-axis oriented and showed a high piezoelectric constant d31 of −3.5 pC/N. Using this value, we calculated properties of the diamond cantilever AFM probes of various dimensions and of 5 μm in thickness with a ZnO sensor and actuator of 1 μm in thickness. The resolution of displacement and actuation force for a probe of 150 μm in length and 50 μm in width were estimated to be about 1.5 nm at a resolution of charge measurement of 1×10−15 C and 7 μN at an applied voltage of 10 V, respectively. [Copyright &y& Elsevier]