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Samarium supersensors Piezoelectric materials produce electric charge in response to changes in stress and are thus good sensor materials. One challenge has been growing single-crystal piezoelectrics with uniform properties. As of now, much of the crystal is discarded because of compositional variations. Li et al. synthesized single crystals of samarium-doped Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 that have uniform and extremely high piezoelectric properties (see the Perspective by Hlinka). These crystals are ideal for a variety of sensing applications and could reduce cost by eliminating waste. Science , this issue p. 264 ; see also p. 228

The ability of ferroelectric materials to generate high voltage under shock compression is a fundamental physical effect that makes it possible to create miniature autonomous explosive-driven pulsed power systems. Shock-induced depolarization releases an electric charge at the electrodes of the ferroelectric element, and a high electric potential and a high electric field appear across the element. We performed systematic studies of the electric breakdown field, $E_{b}(d)$ , as a function of the ferroelectric element thickness, $d$ , for Pb(Zr0.95Ti0.05)O3 (PZT 95/5) and Pb(Zr0.52Ti0.48)O3 (PZT 52/48) ceramics compressed by transverse shock waves (shock front propagates perpendicular to the polarization vector) and established a relationship between these two values: $E_{b}(d) = \textrm {const}\cdot d^{-\xi }$ . This law was found to be true in a wide range of ferroelectric element thicknesses from 1 to 50 mm. This result makes it possible to predict ferroelectric generator (FEG) output voltages up to 500 kV and it forms the basis for the design of ultrahigh-voltage FEG systems.

Relaxor ferroelectric single crystals have triggered revolution in electromechanical systems due to their superior piezoelectric properties. Here the results are reported on experimental studies of energy harvested from (1-y-x)Pb(In1/2Nb1/2)O3–(y)Pb(Mg1/3Nb2/3)O3–(x)PbTiO3 (PIN-PMN-PT) crystals under high strain rate loading. Precise control of ferroelectric properties through composition, size and crystallographic orientation of domains made it possible to identify single crystals that release up to three times more electric charge density than that produced by PbZr0.52Ti0.48O3 (PZT 52/48) and PbZr0.95Ti0.05O3 (PZT 95/5) ferroelectric ceramics under identical loading conditions. The obtained results indicate that PIN-PMN-PT crystals became completely depolarized under 3.9 GPa compression. It was found that the energy density generated in the crystals during depolarization in the high voltage mode is four times higher than that for PZT 52/48 and 95/5. The obtained results promise new single crystal applications in ultrahigh-power transducers that are capable of producing hundreds kilovolt pulses and gigawatt-peak power microwave radiation.

Ferroelectric (FE) films are widely used in electronic devices and low-power FE transducers. There is significant interest in expanding the usage of FE films to ultrahigh-power systems. The results are reported herein on experimental investigations of stress-induced depolarization of single-layer PbZr0.95Ti0.05O3 doped 2% Nb (PZT 95/5) poled FE films subjected to uniaxial adiabatic compression perpendicular and antiparallel to the direction of polarization. It was found that at a stress of 2.4 GPa, the 32-μm-thick films underwent a pressure induced transition to a nonpolar antiferroelectric phase and became completely depolarized in both modes of high strain rate loading. The experimental results indicate that the behavior of stress-induced current generated by longitudinally compressed films is more complicated than under transverse stress. This complex behavior may be caused by the short stress wave transit distance through the film, that is, comparable with the thickness of the stress wave front. The important result is that the specific electric charge released by PZT 95/5 films under stress, 104 μC/cm3, is more than an order of magnitude higher than that released by bulk PZT 95/5 ceramic specimens. It was experimentally demonstrated that transversely compressed miniature PZT 95/5 film specimens with volume less than 1 cm3 are capable of producing pulses of hundreds of amperes of current. This study promises FE film applications in ultrahigh-power systems.Ferroelectric (FE) films are widely used in electronic devices and low-power FE transducers. There is significant interest in expanding the usage of FE films to ultrahigh-power systems. The results are reported herein on experimental investigations of stress-induced depolarization of single-layer PbZr0.95Ti0.05O3 doped 2% Nb (PZT 95/5) poled FE films subjected to uniaxial adiabatic compression perpendicular and antiparallel to the direction of polarization. It was found that at a stress of 2.4 GPa, the 32-μm-thick films underwent a pressure induced transition to a nonpolar antiferroelectric phase and became completely depolarized in both modes of high strain rate loading. The experimental results indicate that the behavior of stress-induced current generated by longitudinally compressed films is more complicated than under transverse stress. This complex behavior may be caused by the short stress wave transit distance through the film, that is, comparable with the thickness of the stress wave front. The i...

In order to protect electronic products from Electrostatic Discharge (ESD) damage, multi-layer ceramic capacitors (MLCC) are often used to bypass the transient ESD energy. Most dielectric materials used in MLCC are nonlinear, since the dielectric constant decreases with increasing voltage, reducing the capacitance value, thus degrading the ESD protection effect. Using a large initial capacitance value will ensure sufficient ESD protection; however, the shunt capacitors also limit the signal bandwidth of the ESD-protected data channel, thus setting a maximal capacitance value at data voltage levels. This paper investigates the nonlinearity of capacitors and suggests improved tradeoff between ESD protection and data bandwidth by using the Antiferroelectric (AFE) capacitors as ESD protection. The dielectric constant of AFE material increases with increasing voltage. The voltage dependence of X7R and AFE capacitors are measured using static and nanosecond transient measurements. The ESD protection effectiveness with different material capacitors are compared by simulation. Due to very limited availability of suitable AFE material samples only hand-made capacitors have tested without investigating the long term stability of the material.

Nonlinear ceramics that provide the basis for high-energy-density and high-temperature capacitors, as well as tunable microwave dielectrics, and their applications are discussed in this article.

Pb(In(0.5)Nb(0.5))O(3)-Pb(Mg(1/3)Nb(2/3))O(3)-PbTiO(3) (PIN-PMN-PT) ferroelectric crystals attracted extensive attentions in last couple years, due to their higher usage temperatures range (> 30°C) and coercive fields (~5kV/cm), meanwhile maintaining similar electromechanical couplings (k(33)> 90%) and piezoelectric coefficients (d(33)~1500pC/N), when compared to their binary counterpart Pb(Mg(1/3)Nb(2/3))O(3)-PbTiO(3). In this article, we reviewed recent developments on the PIN-PMN-PT single crystals, including the Bridgman crystal growth, dielectric, electromechanical, piezoelectric and ferroelectric behaviors as function of temperature and dc bias. Mechanical quality factor Q was studied as function of orientation and phase. Of particular interest is the dynamic strain, which related to the Q and d(33), was found to be improved when compared to binary system, exhibiting the potential usage of PIN-PMN-PT in high power application. Furthermore, PIN-PMN-PT crystals exhibit improved thickness dependent properties, due to their small domain size, being on the order of 1μm. Finally, the manganese acceptor dopant in the ternary crystals was investigated and discussed briefly in this paper.

A new compositional family of relaxor ferroelectrics was investigated based on the high-temperature Bi(Me)O 3 -PbTiO 3 ferroelectric perovskite family. Compositions were fabricated near an estimated morphotropic phase boundary (MPB) of the xBiScO 3-y Pb(Mg 1/3 Nb 2/3 )O 3 -zPbTi03 (xBS-yPMN-zPT) ternary system exhibiting high-temperature relaxor properties of T max ∼250°-350°C and e max ∼10000-24000 at 1 kHz. Analysis of the low-field a.c. permittivity by a Vogel-Fulcher type dependence enabled key parameters of activation energy, E A , and freezing temperature, T f , to be determined. The remanent polarization was studied over a broad temperature range and was observed to show classical ferroelectric square loop hysteresis behavior at temperatures T T max , the deviation temperature, To, was obtained from Curie-Weiss analysis and found to be ∼600°C. A comparison of characteristic electrical properties was made between the high-temperature perovskite relaxors and the classical complex lead relaxor compound, Pb(Mg 1/3 Nb 2/3 )O 3 (PMN).

The substitution of the aliovalent dopant Cr2O3 on the Ti site was investigated in terms of the effects on the dielectric properties at doping levels ranging from 0.1 to 1.0%. No evidence of secondary phases was observed from XRD analysis, but both the permittivity and dielectric loss of 1% Cr2O3 doped CaCu3Ti4O12 were improved with K ≈ 19,000 and tan δ ≈ 0.049 at 1 kHz. Also, 1% Cr2O3 doping was effective at maintaining the high K up to 150 V. From these results, it can be incurred that Cr2O3 doping is an efficient method to achieve a high-K and low loss.

(Na2O,BaO)–Nb2O5–SiO2 and (K2O,SrO)–Nb2O5–SiO2 glass ribbons with varying proportions of alkali and alkaline earth were formed using roller quenching. (Na2O,BaO)–Nb2O5–SiO2 glasses of compositions devitrified to form Ba2NaNb5O15 (in the form of ∼80 nm crystallites in an amorphous matrix) yielded frequency-stable dielectric constants of ∼250 and losses of ∼0.05. Such low losses and frequency stabilities were also observed from (K2O,SrO)–Nb2O5–SiO2 glasses of compositions forming predominantly KSr2Nb5O6 (∼30 nm crystals), yielding dielectric constants of ∼400. Both optimized compositions showed moderate decreases in dielectric constant with increasing temperature.

The effects of solid-solution additives, their concentration, and the thermal processing schedule on the microstructure evolution and microwave properties of Ba2Ti9O20 were studied. The solubility of tin in Ba2Ti9O20 was higher than that of zirconium. Both elements facilitated the formation of phase-pure Ba2Ti9O20 resonators. Ba2Ti9O20 formed most easily with low dopant concentrations (0.82 mol%) (most impressively for ZrO2 substitutions). Extended heat treatment (16 h versus 6 h at a temperature of 1390°C) resulted in volatilization of the grain-boundary liquid phase, which leads to more-porous resonators that have correspondingly lower permittivities. Increasing the dopant concentration resulted in minor increases in the quality factor; doping with zirconium led to slightly higher values (a maximum of 13900 at a frequency of 3 GHz). Increasing the measurement temperature degraded the quality factor (most precipitously for BaTi4O9). The temperature coefficient decreased as the ZrO2 substitution increased but was largely unaffected by the SnO2 concentration. Excess TiO2 in a batch with no other dopants demonstrated degraded microwave properties.

The third generation of advanced relaxor-PT piezoelectric single crystals, Mn:PIN-PMN-PT (manganese doped Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3), has attracted broad attention for high power transducer applications due to their greatly reduced mechanical loss but well-maintained, extremely high electromechanical coupling coefficient. Small signal characterization of Mn:PIN-PMN-PT crystals have been extensively studied. However, systematic large signal tests of Mn:PIN-PMN-PT crystals were urgently needed for further assessing the properties for high power transducer operation. In this work, systematic large signal, quasistatic measurements have been conducted for Mn:PIN-PMN-PT crystals under variable prestress, temperature and electric field. Preliminarily optimized operation domains for high power transducer design have been revealed for [001]-poled crystals for achieving maximum acoustic power density with low hysteretic losses caused by nonlinearity and phase transitions.

Rate-controlled sintering (RCS) of isostatically pressed particulate compacts of ZnO showed lower average grain sizes and intragranular pore densities than constant heating rate temperature controlled sintering. Valid comparisons of this form could only be made after corrections to hardware and software which reduced specimen creep under dilatometer pushrod load, nonuniform pushrod expansion, reproducible specimen temperature determination, thermal expansion during sintering, and instantaneous termination of sintering at the specified end of RCS. The improved microstructures from RCS were attributed to maximized efficiency of densification, optimizing the time and temperatures permitted for grain growth.

The piezoelectric d15 coefficients of 〈111〉-oriented (1−x)Pb(Zn1/3Nb2/3)O3–xPbTiO3 single crystals for x=0.045 and x=0.08 (PZN-4.5%PT and PZN-8%PT) have been measured as functions of dc bias field and frequency using a Zygo laser interferometer system. High d15 values (∼5500 pC/N for PZN-4.5%PT and ∼7500 pC/N for PZN-8%PT) were obtained in the absence of dc bias. d15 decreased as the dc bias was increased. d15 was also found to decrease with increasing frequency, and this frequency dependence decreased at sufficiently large bias fields. Our results suggest that these 〈111〉-oriented crystals are promising materials for high performance shear transducers.

While silicon carbide (SiC) has been found to be a desirable mirror material due to its excellent thermal and mechanical properties, the optical performance of SiC mirrors might be limited by the internal defects introduced in fabrication. Therefore, it is necessary to evaluate the internal conditions of SiC mirror parts before integrating the mirror. This paper presents using a 64-element 30 MHz linear ultrasonic array to detect micro defects in SiC mirrors. To avoid scratching mirrors, instead of placing the array directly against the SiC mirror samples, water coupling was used in this ultrasonic nondestructive testing (NDT). A modified refraction beamforming scheme for the delay error correction was introduced to address the refraction and the delay errors in beamforming caused by the huge difference in sound speed between water and SiC. B-mode images of a pre-diced SiC sample were acquired and the defect detection ability of the system was evaluated. The imaging system paired with the high frequency ultrasonic array was shown to have the potential in evaluating the quality of SiC mirrors by utilizing the refraction beamforming methodology.

Hydrogen gas (H2) was used to extract B2O3 coatings from boron carbide (B4C) particles, permitting a lower temperature onset of sintering and restricting coarsening via solution and precipitation of B4C in B2O3 liquid. Remnant H2 had to be removed from the furnace before specimens were heated through temperature ranges in which evaporation-condensation coarsening competed with sintering (2010°–2140°C), because the presence of H2 increased the B4C vapor pressure. Heat treatment of B4C compacts in a 50:50 H2-He mixture at 1350°C, followed by a purge of the H2 gas and then rapid heating to 2230°C, resulted in a percentage of theoretical density of 94.7%. This is higher than the value of 92.8%, which was the highest achieved without the use of H2.

Phased array imaging systems provide the features of electronic beam steering and dynamic depth focusing that cannot be obtained with conventional linear array systems. This paper presents a system design of a digital ultrasonic imaging system, which is capable of handling a 64-element 35MHz center frequency phased array transducer. The system consists of 5 parts: an analog front-end, a data digitizer, a DSP based beamformer, a computer controlled motorized linear stage, and a computer for post image processing and visualization. Using a motorized linear stage, C-scan images, parallel to the surface of scanned objects may be generated. This digital ultrasonic imaging system in combination a 35 MHz phased array appears to be a promising tool for NDT applications with high spatial resolution. It may also serve as an excellent research platform for high frequency phased array design and testing as well as ultrasonic array signal algorithm developing using system's raw RF data acquisition function.

The coercive fields (E(C)) of Pb(In₀.₅Nb₀.₅)O₃-Pb(Mg(¹/₃)Nb(²/₃)O₃-PbTiO₃ (PIN-PMN-PT) ternary single crystals were found to be 5 kV/cm, double the value of binary Pb(Mg(¹/₃)Nb(²/₃)O₃-PbTiO₃ (PMNT) crystals, further increased to 6 to 9 kV/cm using Mn modifications. In addition to an increased EC, the acceptor modification resulted in the developed internal bias (E(int)), on the order of ~1 kV/cm. The piezoelectric shear properties of unmodified and Mn-modified PIN-PMN-PT crystals with various domain configurations were investigated. The shear piezoelectric coefficients and electromechanical coupling factors for different domain configurations were found to be2000 pC/N and0.85, respectively, with slightly reduced properties observed in Mn-modified tetragonal crystals. Fatigue/cycling tests performed on shearmode samples as a function of ac drive field level demonstrated that the allowable ac field levels (the maximum applied ac field before the occurrence of depolarization) were only ~2 kV/cm for unmodified crystals, less than half of their coercive field. Allowable ac drive levels were on the order of 4 to 6 kV/cm for Mn-modified crystals with rhombohedral/orthorhombic phase, further increased to 5 to 8 kV/cm in tetragonal crystals, because of their higher coercive fields. It is of particular interest that the allowable ac drive field level for Mn-modified crystals was found to be ≥ 60% of their coercive fields, because of the developed E(int), induced by the acceptor-oxygen vacancy defect dipoles.

Mn doped PIN-PMN-PT single crystals with diameter of 50mm have been successfully grown by the Bridgman method along , and orientations. The effect of the acceptor dopant, Mn, on mechanical loss and other electromechanical properties was studied in comparison with pure PIN-PMN-PT single crystal under high and low electric fields. A complete set of piezoelectric, dielectric and elastic properties was derived from resonance measurements. It was demonstrated that by doping Mn, Q M increases 4–5 times to 700–1000 in -poled longitudinal samples without any compromise in electromechanical coupling (k 33 ). Mn doped PIN-PMN-PT crystals also show strong anisotropy. For -poled longitudinal samples, Q M and E C increase to above 1000 and 8–10kV/cm, respectively, which is comparable to “hard” PZT ceramics. The fatigue behavior was investigated as function of crystal orientation and magnitude of the electric field. Polarization degradation was observed to suddenly occur along orientation above 100 cycles of 15kV/cm bipolar field, while nearly no fatigue was seen along orientation.

The piezoelectric properties of Pb(In(0.5)Nb(0.5))O(3)-Pb(Mg(1∕3)Nb(2∕3))O(3)-PbTiO(3) crystals with various engineered domain configurations were investigated. Rhombohedral and monoclinic∕orthorhombic crystals poled along their crystallographic [011] directions were found to possess macroscopic mm2 symmetry, with "2R" and "1O" domain, respectively. Crystals with the "2R" domain configuration were found to exhibit high extensional piezoelectric coefficients d(33) (∼1300 pC∕N) and d(32) (∼-1680 pC∕N), while crystals with the "1O" configuration possessed high shear coefficients d(15) (∼3500 pC∕N) and d(24) (∼2070 pC∕N), with relatively low extensional piezoelectric coefficients d(33) (∼340 pC∕N) and d(32) (∼-260 pC∕N). The observed results were explained by "polarization rotation" model, as related to their respective domain configurations.

The effects of solid-solution additives, their concentration, and the thermal processing schedule on the microstructure evolution and microwave properties of Ba2Ti9O20 were studied. The solubility of tin in Ba2Ti9O20 was higher than that of zirconium. Both elements facilitated the formation of phase-pure Ba2Ti9O20 resonators. Ba2Ti9O20 formed most easily with low dopant concentrations (0.82 mol%) (most impressively for ZrO2 substitutions). Extended heat treatment (16 h versus 6 h at a temperature of 1390°C) resulted in volatilization of the grain-boundary liquid phase, which leads to more-porous resonators that have correspondingly lower permittivities. Increasing the dopant concentration resulted in minor increases in the quality factor; doping with zirconium led to slightly higher values (a maximum of 13900 at a frequency of 3 GHz). Increasing the measurement temperature degraded the quality factor (most precipitously for BaTi4O9). The temperature coefficient decreased as the ZrO2 substitution increased but was largely unaffected by the SnO2 concentration. Excess TiO2 in a batch with no other dopants demonstrated degraded microwave properties.

Electric fatigue tests have been conducted on pure and manganese-modified Pb(In 0.5 Nb 0.5 )O 3 –Pb(Mg 1/3 Nb 2/3 )O 3 –PbTiO 3 (PIN–PMN–PT) single crystals along different crystallographic directions. Polarization degradation was observed to suddenly occur above 50–100 bipolar cycles in 〈1 1 0〉 oriented samples, while 〈0 0 1〉 oriented samples exhibited almost fatigue free characteristics. The fatigue behavior was investigated as a function of orientation, magnitude of the electric field and manganese dopant. It was found that 〈0 0 1〉 oriented PIN–PMN–PT crystals were fatigue free, due to its small domain size, being on the order of 1 μm. The 〈1 1 0〉 direction exhibited a strong electrical fatigue behavior due to mechanical degradation. Micro/macro cracks developed in fatigued 〈1 1 0〉 oriented single crystals. Fatigue and cracks were the result of strong anisotropic piezoelectric stress and non-180° domain switching, which completely locked the non-180° domains. Furthermore, manganese-modified PIN–PMN–PT crystals were found to show improved fatigue behavior due to an enhanced coercive field.

PMN-PT single crystal 1-3 composite high frequency phased arrays with center frequency of 35 MHz were fabricated and characterized for silicon carbide (SiC) NDE imaging applications. The 35 MHz 64-element array was successfully prototyped using PMN-PT single crystal and PC-MUT technology. The broad bandwidth > 90% and high sensitivity (echo amplitude > 500 mV from the impulse response with 0 gain) was observed with reasonably high uniformity. These high frequency phased arrays are promising for ceramic NDE imaging.

A series of relaxor piezoelectric single crystals, including lead magnesium niobate-lead titanate (PMN-PT) and pure and manganese-doped lead indium niobate-lead magnesium niobate-lead titanate (PIN-PMN-PT and Mn: PIN-PMN-PT), have been developed by a modified Bridgman crystal growth process. These single crystals have been grown along both and with diameters up to 75mm. PIN-PMN-PT possesses the similar electromechanical properties to PMN-PT, while rhombohedral-to-tetragonal phase transition temperature (T rt ) and coercive field (E C ) increased to higher than 120°C and 4.5kV/cm, respectively. By doping with Mn, mechanical quality factor (Q M ) increased above 700 in -poled longitudinal mode without compromising electromechanical coupling (k 33 ), T rt and E C . This work demonstrated that by composition modification, the electromechanical properties of PMN-PT based crystals can be stabilized with respect to operating temperature and electric field.

In this paper, PMN-PT single crystal piezoelectric stack actuators and flextensional actuators were designed, prototyped and characterized for space optics applications. Single crystal stack actuators with footprint of 10 mm x10 mm and the height of 50 mm were assembled using 10 mm x10mm x0.15mm PMN-PT plates. These actuators showed stroke > 65 - 85 microns at 150 V at room temperature, and > 30 microns stroke at 77 K. Flextensional actuators with dimension of 10mm x 5 mm x 7.6 mm showed stroke of >50 microns at room temperature at driving voltage of 150 V. A flextensional stack actuator with dimension of 10 mm x 5 mm x 47 mm showed stroke of approx. 285 microns at 150 V at room temperature and > 100 microns at 77K under driving of 150 V should be expected. The large cryogenic stroke and high precision of these actuators are promising for cryogenic optics applications.

In this paper, the development of a 35 MHz 64-channel Piezoelectric Composite based Micromachined Ultrasound Transducer (PCMUT) phased array for NDE ultrasound application is presented. A 35 MHz PMN-PT single crystal 1-3 composite based PC-MUT phased array was designed with extensive acoustic field and 1D modeling. The initial modeling results demonstrated that the focused detection resolution (10% of -3 dB beam width) could be as small as 30 μm in the azimuth direction. The maximum imaging depth for ceramic samples is around 20 mm. The PC-MUT array being developed will extend the state-of-art NDE phased array technology from approximately 20 MHz to 35 MHz, which will greatly enhance the imaging resolution for a broad range of NDE ultrasound applications.

PIN-PMN-PT (Pb(Infrac12Nbfrac12)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3) single crystals with 26%-59% PIN were successfully grown by Bridgman technique. Elastic, dielectric and piezoelectric properties of ternary PIN-PMN-PT crystals were studied in comparison with PMN-PT (Pb(Mg1/3Nb2/3)O3 - PbTiO3) crystals. It was demonstrated that PIN-PMN-PT crystals possess as excellent piezoelectric properties as PMN-PT crystals, but can be operated at elevated temperature and AC electric field without the depoling issue. TRT of PIN-PMN-PT crystals with 26%-36% PIN were roughly in the range of 115 -135degC, 30-40degC higher than that of PMN-PT crystals; meanwhile, EC were on the order of 4.5-5.6kV/cm, two to three times higher than that of PMN-PT crystals. A full set of measured or derived elastic, piezoelectric and dielectric properties of PIN-PMN-PT crystals are present in this paper.

In this paper a piezoelectric composite based micromachined ultrasound transducer (PC-MUT) technology is presented for fabrication of PMN-PT single crystal piezoelectric composite transducers. Micromachined PMN-PT single crystal 1-3 composites with resonance frequencies of 15 MHz-75 MHz were fabricated and characterized with coupling coefficient of 0.67-0.79. Transducers with a frequency of 75 MHz were prototyped and characterized.

Micromachining of bulk piezoelectric substrates for fabrication of high frequency, broadband piezoelectric composite transducers is reported in this paper. A deep reactive ion etching process was developed for bulk PMN-PT single crystal etching with an aspect ratio of >8. A piezoelectric composite with a resonance of 75 MHz was fabricated and the electromechanical coupling coefficient was measured to be 0.67. A 75 MHz piezoelectric composite transducer was prototyped and pulse echo experiments showed that the transducer bandwidth is about 80 - 90% and the sensitivity was significantly improved (>10 dB gain) relative to a commercial 75 MHz transducer. The developed HF piezoelectric composite transducers hold promise for medical ultrasound imaging, ultrasound NDE, and other novel sensors for biological, medical and industrial process monitoring.

Single crystal piezoelectric composite transducers including 75 MHz PC-MUT (piezoelectric composite micromachined ultrasound transducers), diced 10 MHz and 15 MHz 1-3 composite transducers were successfully demonstrated with broad bandwidth and high sensitivity. In this paper, the design, fabrication and characterization of composite transducers are reported. C-scan experiments for SiC ceramic samples were performed using these composite transducers as well as some commercial NDE transducers. The results suggest that significant improvements in resolution and penetration depth can be achieved in C-scan NDE imaging using single crystal composite broadband transducers.

Dynamic characterization of modified single crystal lead magnesium niobate-lead titanate (PMNT) is presented and compared to PMN-28PT and PMN-32PT compositions. Long thin bars with electrodes on the ends were driven in the 33 mode under free conditions to provide large signal material properties. The measurement technique used in this study combines the frequency dependent complex impedance with the measurement of the sample face velocity using a laser vibrometer. This technique characterizes the fundamental half wave length extensional resonance mode of the bar as a function of increased drive amplitude and provides both the linear and non-linear characteristics as a function of increased vibration amplitude, up to material failure. A modified PMNT composition having a Trt up to 125°C was tested. The modified composition showed similar small signal piezoelectric properties to the baseline material. The large signal characteristics also follow the baseline material trends. Therefore, the modified composition provides similar performance with significantly improved temperature stabilityand is a viable candidate for high power sonar transducers.

The design concept for a single-active layer ultrasound transducer array for simultaneous sub- and second-harmonic imaging of contrast agents was tested for feasibility. Using PMN-PT single crystal in a 1-3 composite, multiple matching layers and a back plate, a design for imaging at 2, 4 and 8 MHz was implemented in a series of transducers. The effects of array pitch and piezocomposite thickness were examined. Transmit and receive sensitivities show the pitch and piezoelectric thickness can vary effects across the passband by more than 10 dB for different transducer parameters. Maximum transmit sensitivities of 230 dB re 1 uPa/V at 1 mm were achieved for the arrays. Contrast agent testing using Definityreg showed the second harmonic could be detected. The sub-harmonic was not detected, and could be due to a low peak pressure from the unfocused array sub- aperture.

Non lead piezoelectric materials with two compositions from the (BiNa)TiO3-(BiK)TiO3 -BaTiO3 system and one composition from the (KNa)NbO3-LiTaO3 system were synthesized using the mixed oxide technique. Piezoelectric and dielectric properties of bulk ceramics were measured and their sensitivity to moisture and poling conditions were compared to determine the optimum composition for thick film processing. The dielectric constants of bulk ceramics were 710~940 and d33's were in the 130 -210 pC/N range. The composition of bulk ceramics that exhibited the best property durability was chosen for thick film screen printing. Processing parameters were optimized to achieve defect-free films. Dielectric loss and hysteresis in polarization were observed to be very sensitive to film quality and 9 mum thick films with compatible properties to bulk ceramics were achieved.

In this paper, the design, fabrication and characterization of PMN-PT single crystal/epoxy composites are reported for NDT ultrasound transducers. Specifically, 1-3 PMN-PT/epoxy composites with center frequencies of 5 MHz - 40 MHz were designed and fabricated using either the dice-and-fill method or a photolithography based micromachining process. The measured electromechanical coefficients for composites with frequency of 5 MHz - 15 MHz were about 0.78-0.83, and the coupling coefficients for composites with frequencies of 25 MHz- 40 MHz were about 0.71-0.72. The dielectric loss remains low (< 0.05). These properties hold promise for advanced NDT ultrasound applications.

In this paper piezoelectric composites are presented for advanced micro and nano electromechanical devices. The properties of piezoelectric composites (1-3 and 2-2 connectivity) were analyzed and a micromachining process for bulk piezo materials deep etching was developed for piezoelectric composites fabrication. As an example, micromachined piezoelectric composites with center frequency of 20–50 MHz were prototyped. The micro-piezoelectric composites were characterized showing unprecedented properties for high frequency ultrasound imaging and M/NEMS applications.Copyright © 2007 by ASME

The need for miniaturization without compromising cost and performance continues to motivate research in advanced capacitor devices. In this report, multilayer ceramic capacitors based on relaxor BaTiO3-Bi(Zn1/2Ti1/2)O3 (BT-BZT) were fabricated and characterized. In bulk ceramic embodiments, BT-BZT has been shown to exhibit relative permittivities greater than 1000, high resistivities (ρ > 1 GΩ-cm at 300 °C), and negligible saturation up to fields as high as 150 kV/cm. Multilayer capacitor embodiments were fabricated and found to exhibit similar dielectric and resistivity properties. The energy density for the multilayer ceramics reached values of ∼2.8 J/cm3 at room temperature at an applied electric field of ∼330 kV/cm. This represents a significant improvement compared to commercially available multilayer capacitors. The dielectric properties were also found to be stable over a wide range of temperatures with a temperature coefficient of approximately −2000 ppm/K measured from 50 to 350 °C, an important...

Relaxor ferroelectric single crystal, PMN-PT, has great potential to be an innovative piezoelectric material in both actuator and transducer applications. Large-size PMN-PT single crystals with diameter of 40-50mm have been successfully grown along different crystallographic directions, including ≪111≫, ≪110≫ and ≪001≫, by Bridgman technique at TRS Technologies. The current status of Bridgman growth will be presented with emphasis on the longitudinal and lateral uniformity of the differently oriented boules evaluated by composition analysis and properties characterization. In ≪001≫-oriented Bridgman growth, very high lateral uniformity has been achieved with the maximum variation in a whole (001) wafer less than ±4% for both piezoelectric coefficient and dielectric constant, which show the significant advantage of ≪001≫-oriented growth.

In this paper low voltage single crystal actuators were investigated using thin PMN-PT plates for applications requiring low voltage, large strain, low profile and/or actuation at cryogenic temperatures. Firstly, single crystal thickness effect on piezoelectric properties was studied by investigating the relationship between electromechanical coupling coefficient of PMN-PT crystals and the crystal thickness. It was found that electromechanical coupling coefficient (kt) of 50 μm, 75 μm and 100 μm PMN-PT single crystal thin plates are 0.5, 0.51, and 0.55, respectively, which are slightly lower than that of bulk single crystal (0.6). A couple of single crystal actuators were then assembled using crystal plates with thickness of 150-200 μm. These actuators were characterized by measuring strain vs. electric field at room temperature and cryogenic temperatures. A 3 mm x 3 mm x 19 mm single crystal stack actuator showed a 21 μm stroke at room temperature under 150 V, and a 10 μm stroke at 60 K under 200 V. A 5 mm x 5 mm x 12 mm single crystal actuator showed 13.5 μm stroke at room temperature under 150 V, and 6 μm stroke at 77 K under 150 V. These low voltage actuators hold promising for space precise positioning and adaptive structures and cryogenic SEM, SPM and STM applications.

In this paper a piezoelectric composite based micromachined ultrasound transducer (PC-MUT) fabrication technology is presented. PMN-PT single crystal posts with side length of 14 mum and height of > 60 mum were fabricated using a deep dry etching method. High frequency (20-50 MHz) PMN-PT single crystal/epoxy 1-3 composites were prepared and the electromechanical coupling coefficient of the composites was ~0.72. Prototype 40 MHz ultrasound transducers showed promising sensitivity and bandwidth

Novel piezoelectric actuators (stack actuator and flextensional actuator) and ultrasonic motors are presented for cryogenic actuations utilizing the excellent cryogenic properties of recently invented single crystal piezoelectrics (PMN‐PT and PZN‐PT crystals). Single crystal piezoelectrics exhibit large increases in strain over conventional piezoelectric ceramics. Furthermore, the crystals have been found to retain appreciable piezoactivity down to temperatures as low as 20K. These cryogenic actuators are very promising for shape control, precision positioning and force control in various NASA, military and civilian applications such as cryogenic adaptive optics for space telescopes, interferometers in terrestrial planet finder missions, interferometers and spectrometers for remote sensing applications.

This paper presents cryogenic actuators for high‐temperature superconducting (HTS) tunable filters. The designated piezo‐tuned‐HTS concept will enable a broad range of civilian and military applications that require precise band selectivity over a broad frequency range. In this paper, low profile flextensional single crystal actuators were developed with 150‐μm stroke at 77 K. This actuator was then used for Superconducting Technologies, Inc. (STI) HTS resonator tuning in liquid nitrogen. A fine tuning using the same actuator shows more than 3% tunability and less than 1‐dB insertion loss variation and the Q is about a few thousands.

Various transverse length extensional modes of single crystal piezoelectrics were evaluated for high power capabilities and compared with the longitudinal "33" mode. Both bar and tube geometries, and d31 and d32 piezoelectric modes were explored. The elastic, piezoelectric and dielectric properties were evaluated under dynamic conditions using a matrix of stress, temperature and electric field conditions. Crystallographic orientation significantly affected domain stability; poling along the lang001rang axis showed a higher phase transition point, relative to stress and temperature, than the lang110rang orientation. The optimized transverse mode (d31 ) showed significantly improved properties due to the orthogonal relationship between electric field and pre-stress; strains over 0.2% were recorded

(1-x)BiScO3-xPbTiO3 (BSPT) polycrystalline material with a morphotropic phase boundary (MPB) composition (x=0.64) exhibits a high Curie temperature (TC) about 450°C and good piezoelectric properties with d33 values around 460pC/N. Manganese (Mn) modified BSPT was utilized in order to increase the electric resistivity and RC time constant. At 450°C, BSPT66-Mn ceramic exhibited a resistivity of 3x107 Ohm.cm and RC value of 0.08s, respectively, significantly higher than the values for undoped BSPT and commercial PZT5 materials. The manganese additive shifts TC of BSPT materials to lower temperatures, which were found to be 442°C and 462°C for modified BSPT64 and BSPT66, respectively. The piezoelectric behavior for the modified BSPT material was found to deteriorate slightly owing to the hardening effect of manganese, but showed superior temperature stability and enhanced resistivity. The detailed temperature dependent properties were studied in this work and compared to commercial PZT5 materials. The complete set of materials constants, including the elastic sij, cij, piezoelectric dij, eij, gij, hij, dielectric and electromechanical kij values were determined using resonance technique and derived from the experimental data.

TRS is developing new actuators based on single crystal piezoelectric materials such as Pb(Zn1/3Nb2/3)1-xTixO3 (PZN-PT) and Pb(Mg1/3Nb2/3)x-1TixO3 (PMN-PT) which exhibit very high piezoelectric coefficients (d33 = 1800-2200 pC/N) and electromechanical coupling factors (k33 > 0.9), respectively, for a variety of applications, including active vibration damping, active flow control, high precision positioning, ultrasonic motors, deformable mirrors, and adaptive optics. The d32 cut crystal plate actuators showed d32 ~ -1600 pC/N, inter-digital electroded (IDE) plate actuators showed effective d33 ~ 1100 pC/N. Single crystal stack actuators with stroke of 10 μm-100 μm were developed and tested at both room temperature and cryogenic temperatures. Flextensional single crystal piezoelectric actuators with either stack driver or plate driver were developed with stroke 70 μm - > 250 μm. For large stroke cryogenic actuation (> 1mm), a single crystal piezomotor was developed and tested at temperature of 77 K-300K and stroke of > 10mm and step resolution of 20 nm were achieved. In order to demonstrate the significance of developed single crystal actuators, modeling on single crystal piezoelectric deformable mirrors and helicopter flap control using single crystal actuators were conducted and the modeling results show that more than 20 wavelength wavefront error could be corrected by using the single crystal deformable mirrors and +/- 5.8 ° flap deflection will be obtained for a 36" flap using single crystal stack actuators.© (2005) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

TRS is developing new transducers based on single crystal piezoelectric materials such as Pb(Mg1/3Nb2/3)x-1TixO3 (PMN-PT). Single crystal piezoelectrics such as PMN-PT exhibit very high piezoelectric coefficients (d33 ~ 1800 to >2000 pC/N) and electromechanical coupling factors (k33 > 0.9), respectively, which may be exploited for improving the performance of broad bandwidth and high frequency sonar. Apart from basic performance, much research has been done on reducing the size and increasing the output power of tonpilz transducers for sonar applications. Results are presented from two different studies. "33" mode single crystal tonpilz transducers have reduced stack lengths due to their low elastic stiffness relative to PZTs, however, this produces non-ideal aspect ratios due to large lateral dimensions. Alternative "31" resonance mode tonpilz elements are proposed to improve performance over these "33" designs. d32 values as high as 1600 pC/N have been observed, and since prestress is applied perpendicular to the poling direction, "31" mode Tonpilz elements exhibit lower loss and higher reliability than "33" mode designs. Planar high power tonpilz arrays are the optimum way to obtain the required acoustic pressure and bandwidth for small footprint, high power sensors. An important issue for these sensors is temperature and prestress stability, since fluctuations in tonpilz properties affects power delivery and sensing electronic design. TRS used the approach of modifying the composition of PMN-PT to improve the temperature dependence of properties of the material. Results show up to a 50% decrease in temperature change while losing minimal source level.© (2005) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A novel single crystal piezomotor is presented for large stroke, high precision, cryogenic actuation with the capability of position set-hold at power-off. Single crystal linear motors with/without screw are prototyped and characterized at both room and cryogenic temperatures. Stroke of >10 mm, step resolution /spl sim/20 nm, response time /spl sim/2 ms, and driving voltage of 60 V/sub p-p/ were obtained with the prototypes. The linear motor without screw operated successfully in a liquid nitrogen environment (77 K).