Transverse Piezoelectric Properties Research Articles

Temperature dependence of complete sets of material constants of Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 crystals using different poling methods

The complete sets of material constants of <001>-oriented two wafers (HP: high-performance and LP: low-performance) using direct current poling (DCP) and alternating current poling (ACP) were investigated. ACP can improve the longitudinal and transverse piezoelectric properties (about 20% increase in both d31 and d33) and decrease the shear properties (about 40% decrease in d15). The compliance constants SEij of both ACP HP and LP samples have the similar change trend (the absolute of SE11, SE12, SE13, SE33, SE66 increasing, the SE44 decreasing), while most stiffness constants CEij of both ACP HP and LP samples show the different change trend. The values of CE11, CE12, CE13 of ACP LP samples increase by at least 50% while ACP HP samples decrease by about 5%. As temperature elevated, the dielectric properties (εT11/ε0, εT33/ε0), piezoelectric properties (d15, d31, d33) and electromechanical coupling coefficients (k15, k33) increased steadily, while the k31 keep stable.

Complete Sets of Material Constants of [001]-Poled 0.72Pb(Mg1/3Nb2/3)O3- 0.28PbTiO3 Single Crystals Using Alternating Current Poling.

Alternating current poling (ACP) is an effective method to improve the piezoelectric performance of relaxor-PbTiO3 (PT) ferroelectric single crystal. 0.72Pb(Mg1/3Nb2/3)O3-0.28PbTiO3 (PMN-PT) single crystals have been used to fabricate piezoelectric transducers for medical imaging. Up to date, there are no reports about the full matrix material constants of PMN-0.28PT single crystals poled by ACP. Here, we report the complete sets of elastic, dielectric, and piezoelectric properties of [001]-poled PMN-0.28PT single crystals by direct current poling (DCP) and ACP through the resonance method. The results show that [001]-poled rhombohedral PMN-0.28PT single crystals exhibit the enhancement of longitudinal and transverse piezoelectric properties ( d33 ∼2000 pC/N, d31 ∼-1010 pC/N) after ACP. Compared with DCP samples ( d33 ∼1660 pC/N, d31 ∼-780 pC/N), the values of d33 and d31 increase 20% and 29%, respectively. While the d15 value decrease from 110 pC/N for DCP sample to 90 pC/N for ACP sample, showing the decrease in transverse shear piezoelectric properties. In addition, the elastic stiffness coefficients c11 , c12 , c13 , the elastic compliance coefficients s11 , s12 , and the dielectric constants ε11 , ε33 have great change compared with DCP and ACP samples. This variation of the property matrices provides a reference for high-performance piezoelectric device design.

Nonlinearity in inverse and transverse piezoelectric properties of Pb(Zr0.52Ti0.48)O3 film actuators under AC and DC applied voltages

The motion of domain walls is a crucial factor in piezoelectric properties and is usually related to the irreversible and hysteretic behaviors. Herein, we report on the investigation of inverse and transverse piezoelectric coefficients of capacitor-based and microcantilever-based Pb(Zr0.52Ti0.48)O3 films with a change in the DC bias and the AC applied voltage. A large inverse piezoelectric strain coefficient of about 350 p.m./V, and a low strain hysteresis of about 7.1%, are achieved in the film capacitors under a low applied voltage of 2 V (20 kV/cm) which can benefit the actuators for motion control in high-precision systems. The field-dependences of the transverse piezoelectric coefficients, obtained from four-point bending and microcantilever displacement, are in good agreement with each other. The results also reveal that the irreversible domain-wall motion is attributed to the nonlinearity in the field-dependent piezoelectric strain and cantilever displacement.

Enhanced transverse piezoelectric properties by composition and poling electric field induced phase transition in PIN–PMN–PT single crystal near morphotropic phase boundary

A monoclinic phase is the bridge between the rhombohedral and tetragonal phases in the Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 (PIN–PMN–PT) single crystal near the morphotropic phase boundary (MPB), which is related to the superior piezoelectric performance. In this paper, the different phase transition process in the unpoled PIN–PMN–PT single crystals near MPB induced by composition variation was presented first. Based on this, direct current poling (DCP) and alternating current treatment (ACT) were applied on these samples. Also, the crystals by DCP–ACT have shown a more complex ferroelectric phase transition process than that by DCP, which is related to the induced monoclinic phase by applying an AC electric field. The transverse piezoelectric properties of the PIN–PMN–PT single crystal with various compositions by DCP and DCP–ACT were compared. ACT enhanced the electromechanical coupling coefficient k31, elastic compliance constant S11E, and dielectric permittivity ε33T/ε0 of the pre-DCP PIN–PMN–PT single crystals in the macrorhombohedral phase. As a result, the transverse piezoelectric constant d31 of the crystals with various compositions was enhanced to be −1240, −1663, and −1252 pC/N by DCP–ACT, which were 61.7%, 73.0%, and 60.8% higher than that by DCP. However, ACT has little effect on the pre-DCP PIN–PMN–PT crystal with macrocoexistence of rhombohedral and monoclinic phases. The AC electric field could be a useful way for tuning the coexistence of rhombohedral and monoclinic phases in the PIN–PMN–PT crystal near MPB to achieve high transverse piezoelectric performance.

Temperature dependence of the transverse piezoelectric properties in the [001]-poled 0.25Pb(In1/2Nb1/2)O3-0.42Pb(Mg1/3Nb2/3)O3-0.33PbTiO3 single crystal with alternating current treatment

In this work, the transverse piezoelectric properties of the pre-direct current poled (DCP) 0.25Pb(In1/2Nb1/2)O3-0.42Pb(Mg1/3Nb2/3)O3-0.33PbTiO3 (0.25PIN-0.42PMN-0.33PT) single crystals were enhanced by the alternating current treatment (ACT) of 10 kVp/cm (5.8 kVrms/cm), 50 Hz, and 20 cycles. The transverse piezoelectric constant d31 of −1560 pC/N and electromechanical coupling coefficient k31 of 0.92 at room temperature were achieved in the DCP-ACT crystal, which were, respectively, 80% and 11% higher than those of the DCP crystal (d31=−870pC/N,k31=0.83) . Meanwhile, the elastic compliance constant S11E and dielectric permittivity ε33T/ε0 of the DCP-ACT crystal were, respectively, 78% and 46% higher than those of the DCP crystal. Based on the temperature dependence of dielectric properties and resonance curves, the d31, ε33T/ε0, and S11E of the DCP-ACT crystal were higher than those of the DCP crystal in the R phase region. The DCP-ACT crystal also showed a higher TFerro (110 °C) than the DCP crystal (96 °C), which was related to the intermediate phase induced by ACT. The d31 at Tferro of the DCP-ACT crystal can be −3810 pC/N, which was 2.3 times that of the DCP crystal (−1680 pC/N). In the T phase region, the DCP-ACT crystal presented a high ε33T/ε0 and attenuated impedance resonance. Moreover, ACT also affected the ferroelectric to paraelectric phase transition. This could be related to the nanoscale heterogeneous polar region induced by ACT, which enhanced the inhomogeneous state in the relaxor-based ferroelectric single crystal. ACT is a potential way for improving the transverse piezoelectric properties of the PIN-PMN-PT single crystal.

Dependency of direct and inverse transverse piezoelectric properties on composition in self-polarized epitaxial (KxNa1−x)NbO3 films grown via a hydrothermal method

(KxNa1−x)NbO3 films that were approximately 3 μm in thickness and with various x values were systematically deposited at 240 °C on (100)cSrRuO3//(100)SrTiO3 substrates using a hydrothermal method. Direct and inverse transverse piezoelectric coefficients, e31,f, near 0 kV cm−1 were approximately −5.0 C m−2 for the as-deposited films with a wide range of x values without any poling treatment. A large difference in e31,f value was not observed before or after poling treatment upon applying a positive electric field, suggesting that the as-deposited (KxNa1−x)NbO3 films with x = 0.36–0.88 were almost fully in a self-polarized state. (KxNa1−x)NbO3 films with x = 0.36–0.88 without any poling treatment showed a figure of merit for an energy harvester (FOM = e31,f2/εr) above 0.13, as calculated directly from e31,f. These FOM values are relatively high compared with the reported ones for other lead-free films that have a perovskite structure.

Transverse piezoelectric properties of Mn-doped Bi0.5Na0.5TiO3 thin films

Lead-free (Bi0.5Na0.5)(Ti1-xMnx)O3 (BNTMn-x; x = 0, 0.0025, 0.0050, 0.0100) thin films were fabricated using a chemical solution deposition method on Pt/TiO2/SiO2/Si substrate. The effect of Mn substitution on crystal structures, surface morphologies, and ferroelectric and transverse piezoelectric properties of BNTMn-x thin films was investigated. The 0.5 mol% Mn-doped (Bi0.5Na0.5)(Ti0.995Mn0.005)O3 thin film exhibited a well-saturated ferroelectric P-E hysteresis loop at room temperature. A remnant polarization (Pr) of 16 μC/cm2 was obtained for the BNTMn-0.0050 film at an applied electric field of 400 kV/cm. In addition, a 1.12-μm-thick BNTMn-0.0050 film was applied as a cantilever. The Pt/BNTMn-0.0050/Pt/TiO2/SiO2/Si unimorph cantilever exhibited a high transverse piezoelectric coefficient (e31∗) of 2.43 C/m2.

VDF-content-guided selection of piezoelectric P(VDF-TrFE) films in sensing and energy harvesting applications

Worldwide energy crisis and environmental pollution issues are driving people to seek for clean energy harvesting technologies as alternative and/or complementary energy sources for traditional fossil fuel, in which piezoelectric nanogenerators are extensively studied for mechanical energy harvesting due to their high energy density, simple architectures and excellent scaling-down capacity. Poly(vinylidene fluoride) (PVDF) and its copolymer with trifluoroethylene (P(VDF-TrFE)) are mostly studied piezoelectric polymers. Recent work indicated that the largest longitudinal coefficient occurred at the morphotropic phase boundary of P(VDF-TrFE) with 50 mol.% VDF content (CVDF), while P(VDF-TrFE) with higher CVDF was mostly studied. Thus it is indispensable to further understand the influence of CVDF on piezoelectric performance in order to optimize the design of P(VDF-TrFE) based sensors and energy harvesters in various practical applications. Here we made a systematic investigation of the dependence of longitudinal and transverse piezoelectric properties on CVDF in commercially available 50/50, 55/45 and 70/30 copolymers. Experimental results indicated that 50/50 copolymer presented the largest longitudinal piezoelectric property and thus provided the best electric response for tactile sensing while 70/30 one showed the most outstanding transverse piezoelectricity and applied for monitoring the bending of fingers. In energy harvesting experiments at maximum strain of 1.2% and frequency of 0.6 Hz, 70/30 copolymer showed the largest power density of 4.96 nW/mm2, while 55/45 copolymer had the highest energy conversion efficiency of 1.03%. Device performance was expected to be further improved by controlling film quality and microstructures.

Transverse resonance orthogonal beam (TROB) mode for broadband underwater sound generation

New-generation relaxor-based single crystals exhibit excellent transverse piezoelectric properties and extremely high Poisson’s ratio, making possible a drive mode for underwater sound generation, hereafter referred to as the Transverse Resonance Orthogonal Beam (TROB) mode. Unlike conventional transverse width (CTW) mode in which the resonating direction and the acoustic beam direction are identical, in the TROB mode, the active material is set in resonance in half-wavelength mode in one transverse direction and the acoustic beam is generated in the CTW beam direction, the latter being orthogonal to the resonating transverse direction. For direct drive (pistonless) projectors made of [011]-poled PZN-5.5%PT single crystal of ≤62mm3 in volume, the source levels of underwater sound generated via respective TROB and CTW modes are comparable and can be >180dB re 1μPa @ 1m, which can be combined to advantage to form a broad bandwidth underwater projector. Due to low sound velocities in lead-based relaxor single crystals, the lateral dimensions of direct drive projectors utilizing the TROB excitation mode can be kept at or less than λw/2 in the design, λw being wavelength of sound of the design frequency in water. This makes possible the fabrication of broadband projector arrays via the TROB mode.

Nonlinear Dynamic Analysis of Macrofiber Composites Laminated Shells

This work presents the nonlinear dynamical analysis of a multilayer d31 piezoelectric macrofiber composite (MFC) laminated shell. The effects of transverse excitations and piezoelectric properties on the dynamic stability of the structure are studied. Firstly, the nonlinear dynamic models of the MFC laminated shell are established. Based on known selected geometrical and material properties of its constituents, the electric field of MFC is presented. The vibration mode-shape functions are obtained according to the boundary conditions, and then the Galerkin method is employed to transform partial differential equations into two nonlinear ordinary differential equations. Next, the effects of the transverse excitations on the nonlinear vibration of MFC laminated shells are analyzed in numerical simulation and moderating effects of piezoelectric coefficients on the stability of the system are also presented here. Bifurcation diagram, two-dimensional and three-dimensional phase portraits, waveforms phases, and Poincare diagrams are shown to find different kinds of periodic and chaotic motions of MFC shells. The results indicate that piezoelectric parameters have strong effects on the vibration control of the MFC laminated shell.

Improved transverse piezoelectric properties in {110}-oriented B-site acceptor doped PLZT (8/65/35) thin films

ABSTRACTSuperior piezoelectric properties of lead-based perovskite type solid solution systems such as PLZT, having compositions near morphotropic phase boundary (MPB) make them ideal candidates for MEMS. The dielectric and piezoelectric characteristics in such perovskite based thin films are related to their structure and texture. In this study, we report the influence of aliovalent B-site acceptor dopants (Fe3+, Cu2+ and Mn3+) on the structure, dielectric and piezoelectric properties of {110}- preferentially oriented PLZT (8/65/35) thin films. Thin films having a thickness of 2.0 µm were prepared on silicon substrates (111) Pt/Ti/SiO2/Si by Sol-gel spin coating technique. The preferential crystallographic orientation and crystalline phase formation in the thin films were analysed by X-ray diffraction and Raman spectroscopy respectively. The improved transverse piezoelectric coefficient, e31,f and electric field induced bipolar strain characteristics of the acceptor doped PLZT films have been correlated with their crystal structure. Mechanism for higher bipolar strain in Cu2+ and Mn3+ doped PLZT films have also been studied and are reported.

MoP-19 FABRICATION OF PIEZOELECTRIC MULTILAYER THIN-FILM ACTUATORS

We proposed a novel fabrication method of multilayer thin-film piezoelectric actuators composed of 500 nm-thick Pb(Zr,Ti)O_3 (PZT) layers by a single sputtering deposition process. This method enables the fabrication of multilayered piezoelectric thin films with separated intermediate electrodes on SOI substrates without photolithography. We successfully improved, for the first time, the effective transverse piezoelectric properties utilizing the multilayer thin-film structure with increasing a number of PZT layers. We also confirmed that the multilayer thin-film structure enhanced the dielectric properties with increasing a number of PZT layers.

Power-generation performance of lead-free (K,Na)NbO3 piezoelectric thin-film energy harvesters

We fabricated piezoelectric energy harvesters with lead-free (K,Na)NbO3 (KNN) thin films and compared their power-generation performance with that of Pb(Zr,Ti)O3 (PZT) thin film energy harvesters. The KNN and PZT thin films were deposited on Pt/Ti/Si substrates by rf-magnetron sputtering. The transverse piezoelectric properties of the KNN and PZT films were essentially the same, e31,f∼−11C/m2. The peak average output power of the unimorph cantilevers of KNN/Si and PZT/Si were 1.1 and 1.0μW, respectively. Thus, the performance of lead-free KNN thin films as a piezoelectric energy harvester is comparable to that of PZT films.

Complete set of elastic, dielectric, and piezoelectric coefficients of [−1 0 1] poled 0.23Pb(In 1/2Nb 1/2O 3)–0.45Pb(Mg 1/3Nb 2/3)O 3–0.32PbTiO 3 single crystals

In order to better utilize the superior transverse and shear piezoelectric properties of 0.23Pb(In 1/2Nb 1/2O 3)–0.45Pb(Mg 1/3Nb 2/3)O 3–0.32PbTiO 3 single crystals near the morphotropic phase boundary, a complete set of elastic, dielectric, and piezoelectric coefficients of [ 1 ¯ 0 1 ] poled single crystal were determined by resonance and ultrasonic methods at room temperature. The electromechanical coupling coefficient k 32 and transverse piezoelectric coefficient d 32 can reach 0.94 and −2073 pC/N, respectively. At the same time, electromechanical coupling coefficient k 15 and shear piezoelectric constant d 15 are as high as 0.91 and 2526 pC/N. This complete set of material properties will provide convenience for device designs and fundamental theoretical studies such as applications in high-sensitivity medical ultrasonic transducers and large displacement actuators.

Complete sets of elastic, dielectric, and piezoelectric properties of flux-grown [011]-poled Pb(Mg1∕3Nb2∕3)O3-(28–32)% PbTiO3 single crystals

Complete sets of elastic, dielectric, and piezoelectric properties of flux-grown rhombohedral PMN-(28–30)%PT and orthorhombic PMN-32%PT single crystals, poled along the [011]-thickness direction, have been determined. This crystal cut exhibits very high longitudinal-extension, transverse, and shear piezoelectric properties when existing in the rhombohedral state (for PMN-28%PT and PMN-30%PT) but much inferior properties when existing in the ovepoled orthorhombic state (notably for PMN-32%PT). Careful control of crystal composition and poling conditions is thus important when using PMN-PT single crystals in piezoelectric devices.

Piezoelectric Properties of Epitaxial NaNbO3 Thin Films Deposited on (001)SrRuO3/Pt/MgO Substrates

Sodium niobate (NaNbO3, NN) thin films were deposited on (001)SrRuO3/Pt/MgO substrates by rf magnetron sputter deposition. The X-ray diffraction (XRD) pattern of the sputtered NN thin films showed epitaxial growth with a (001)-oriented perovskite structure. From the reciprocal space maps, the lattice parameters of the in-plane and out-of-plane directions were a=0.392 nm and c=0.395 nm, respectively. The relative dielectric constant εr and the range of the dielectric loss tan δ were about 270 and 0.05–0.13 at 1 kHz, respectively. The P–E hysteresis loop showed clear ferroelectricity with spontaneous polarization Ps of 20 µC/cm2 and coercive electric field Ec of 50 kV/cm. The transverse piezoelectric properties were evaluated from the tip displacement of NN/MgO unimorph cantilevers. The transverse piezoelectric coefficient e31* (=d31/s11E) was -0.9 C/m2, which is almost compatible with that of the bulk NN ceramics. The tip deflection showed typical butterfly curves owing to the polarization reversal, indicating that the sputtered NN thin films had a high piezoelectric performance.

Complete set of elastic, dielectric, and piezoelectric constants of orthorhombic 0.71Pb(Mg1∕3Nb2∕3)O3–0.29PbTiO3 single crystal

In order to better utilize the superior transverse piezoelectric properties of [011] poled (1−x)Pb(Mg1∕3Nb2∕3)O3–xPbTiO3 single crystals with the composition near the morphotropic phase boundary, a complete set of elastic, dielectric, and piezoelectric constants of [011] poled 0.71Pb(Mg1∕3Nb2∕3)O3–0.29PbTiO3 single crystal was measured by ultrasonic and resonance methods at room temperature. The electromechanical coupling coefficient k32 and transverse piezoelectric constant d32 can reach 0.94 and −1883pC∕N, respectively. This complete set of material properties will provide convenience for device designs and fundamental theoretical studies.

Transverse-Mode Properties of [011]-Poled Pb(Zn1/3Nb2/3)O3–PbTiO3 Single Crystals: Effects of Composition, Length Orientation, and Poling Conditions

The poling responses of [011]-poled Pb(Zn1/3Nb2/3)O3–PbTiO3 [PZN–PT] single crystals of a range of compositions and two length orientations have been investigated. The results show that [011]-poled PZN–PT single crystals of [100]-length-cut exhibit much superior transverse properties than [011]-length-cut crystals. Extremely high d31 values of -(3000–4000) pC/N and k31∼0.90–0.96 were obtained for PZN–7%PT optimally [011]-poled crystals. This composition, however, shows degraded dielectric and piezoelectric properties when poled at ≥0.6 kV/mm. In contrast, PZN–4.5%PT and PZN–6%PT single crystals show no signs of overpoling even when poled up to 2.0 kV/mm, exhibiting d31≈-(2700–3200) pC/N and k31∼0.90–0.92 (for PZN–6%PT) and d31≈-1500 pC/N and k31∼0.86–0.90 (for PZN–4.5%PT), respectively. The presence of certain amounts (i.e., 10–15%) of orthorhombic phase in a rhombohedral matrix has been found to be responsible for the superior transverse piezoelectric properties of optimally [011]-poled PZN–(6–7)%PT.

PREPARATION AND PIEZOELECTRIC PROPERTIES OF SOL-GEL-DERIVED NB-DOPED PZT FILMS FOR MEMS APPLICATIONS

ABSTRACT Sol-gel-derived niobium (Nb)-doped lead zirconate titanate (PZT) films have been deposited on silicon substrates with a lead titanate seeding layer by the multiple-spin-coating technique. The doping level of Nb ranges from 0 to 2 mol%. With the seeding layer, the PZT films can crystallize well into the perovskite phase at a low temperature of 550°C for 2 h. The films are dense and have good dielectric and piezoelectric properties. Effective longitudinal and transverse piezoelectric coefficients (d33,c and e31,c) of the films have been measured. Our results reveal that the Nb dopant effects on the PZT films are very similar to the experimentally-known effects on the corresponding bulk ceramics, i.e. enhancing both the longitudinal and transverse piezoelectric properties. For the PZT film doped with 1 mol% Nb, the observed values of d33,c and e31,c are 74 pm/V and 12.8 C/m2, respectively.

Dielectric and piezoelectric properties of [0 0 1] and [0 1 1]-poled relaxor ferroelectric PZN–PT and PMN–PT single crystals

The properties of PZN–PT and PMN–PT single crystals of varying compositions and orientations have been investigated. Among the various compositions studied, [0 0 1]-optimally poled PZN-(6–7)%PT and PMN-30%PT exhibit superior dielectric and piezoelectric properties, with K T ≈ 6800–8000, d 33 ≈ 2800 pC/N, d 31 ≈ −(1200–1800) pC/N for PZN-(6–7)%PT; and K T = 7500–9000, d 33 = 2200–2500 pC/N and d 31 = −(1100–1400) pC/N for PMN-30%PT. These two compositions are also fairly resistant to over-poling. The [0 0 1]-poled electromechanical coupling factors ( k 33, k 31 and k t ) are relatively insensitive to crystal composition. [0 1 1]-optimally poled PZN-7%PT single crystal also exhibits extremely high d 31 values of up to −4000 pC/N with k 31 ≈ 0.90–0.96. While [0 1 1]-poled PZN-7%PT single crystal becomes over-poled with much degraded properties when poled at and above 0.6 kV/mm, PZN-6%PT crystal shows no signs of over-poling even when poled to 2.0 kV/mm. The presence of a certain amount (i.e., 10–15%) of orthorhombic phase in a rhombohedral matrix has been found to be responsible for the superior transverse piezoelectric properties of [0 1 1]-optimally poled PZN-(6–7)%PT. The present work shows that flux-grown PZN–PT crystals exhibit superior and consistent properties and improved over-poling resistance to flux-grown PMN–PT crystals and that, for or a given crystal composition, flux-grown PMN–PT crystals exhibit superior over-poling resistance to their melt-grown counterparts.