Our previous efforts were focused on designing, constructing, and investigating miniature shock-wave ferroelectric generators (FEGs) based on Pb(Zr 0.52 Ti 0.48 )O 3 poled ferroelectric ceramics (that is widely used in modern technology). In this paper, we extended our efforts by exploring a different type of ferroelectric materials, i.e., Pb(Zr 0.95 Ti 0.05 )O 3 (PZT 95/5), for designing miniature autonomous shock-wave FEGs. The performance of autonomous ultrahigh-voltage FEGs based on transverse explosive shock depolarization of poled PZT 95/5 ferroelectric ceramics was studied. As a result of this paper, miniature generators (38 mm in diameter) that are capable of producing output voltage pulses with amplitudes exceeding 120 kV and pulsewidths of 3 μs were developed.

Niobium doped lead zirconate titanate (95/5 NbPZT) undergoes a hydrostatic pressure induced ferroelectric rhombohedral to antiferroelectric orthorhombic phase transformation (FE-AFE). This work reports on the experimental characterization of the large field dielectric response to unipolar electric field as it passes through the forward and reverse FE-AFE transformations. The poled ceramic was hydrostatically depoled by driving the FE-AFE phase transformation and stress-strain and stress-electric displacement responses were measured. After this initial characterization, specimens of 95/5 NbPZT were subjected to unipolar electric field loading at different hydrostatic pressure levels. Electric field was varied from zero to 1 MV/m at a series of fixed pressure levels between zero and 550 MPa. This resulted in minor hysteresis loops with the area inside the loops dependent on both pressure and electric field amplitude. Two different slopes were taken from the D-E loops, identified as the small field and large field slopes. Each changed with pressure and displayed distinct jumps at the forward and reverse FE-AFE phase transformations. The area within the loops in the ferroelectric regime, attributed to domain wall motion, increased as pressure was increased and dropped abruptly as the material passed through the pressure induced phase transformation.

Photoluminescence for PbMg 1/3 Nb 2/3 O 3 (PMN)– PbIn 1/2 Nb 1/2 O 3 (PIN) solid solutions in the temperature ranging from 35 to 295 K have been obtained for the first time. An abrupt photoluminescence enhancement of the system has been observed to occur at ∼210 K, which can be attributed to the growing and merging of dynamic polar microregions or to the phase transformation of the material at this temperature. The PIN content has been found to affect the photoluminescence of the PMN-PIN system significantly. The photoluminescence mechanism for PMN-PIN has been studied.

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.

Photoluminescence for PbMg1/3Nb2/3O3 (PMN)– PbIn1/2Nb1/2O3 (PIN) solid solutions in the temperature ranging from 35 to 295 K have been obtained for the first time. An abrupt photoluminescence enhancement of the system has been observed to occur at ∼210 K, which can be attributed to the growing and merging of dynamic polar microregions or to the phase transformation of the material at this temperature. The PIN content has been found to affect the photoluminescence of the PMN-PIN system significantly. The photoluminescence mechanism for PMN-PIN has been studied.

Our previous efforts [1-7] were focused on designing, constructing and investigating miniature shock wave ferroelectric generators (FEGs) based on Pb(Zr 0.52 Ti 0.48 )O 3 (PZT 52/48) poled ferroelectric ceramics (that is widely used in modern technology). In this paper, we extended our efforts to development of FEGs utilizing different type of ferroelectric materials, i.e. Pb(Zr 0.95 Ti 0.05 )O 3 (PZT 95/5). The design of autonomous ultrahigh-voltage FEGs based on transverse explosive shock depolarization of poled PZT 95/5 ferroelectric ceramics was explored and studied. As a result of this work, miniature generators (diameter 38 mm) that are capable of producing output voltage pulses with amplitudes exceeding 120 kV and pulse widths of 3 μs were developed.

High temperature sensors are desired for down-hole well monitoring, future propulsion components, as well as improving performance and maintainability of power production facilities and other rotary combustion engines. Recently discovered high temperature oxyborate crystals showed stable piezoelectric properties and high resistivity at temperatures close to its melting point (∼ 1500°C, or 2730°F ), which is very promising for high temperature sensor applications. In this paper the feasibility of using oxyborate based high temperature piezoelectric crystal (HTPC) for high temperature piezoelectric sensor applications is demonstrated. Oxyborate HTPC with various crystal cuts and vibration modes were investigated to obtain high temperature resistivity, dielectric, piezoelectric and thermal expansion properties. YCa4O(BO3)3 crystals (YCOB) showed excellent piezoelectricity, low dielectric loss and high resistivity at temperatures up to 1000°C (> 1800°F). The measured thermal expansion coefficients of YCOB are about ∼3–8 ppm/K, depending on different orientations. High temperature accelerometers were demonstrated using YCOB HTPC at temperatures up to 1000°C with sensitivity remaining steady (∼ 2.4 pC/g) across the temperature range of 20°C-1000°C.

High temperature power electronics have become a vital aspect of future designs of compact power converters for applications including power conditioning and distributed motor/actuator controls. However, the development of high temperature capacitors had lagged far behind other system components (e.g. semiconductor switches and that can operate at temperature >200 degrees C). The performance of these systems would benefit significantly from components and packaging designed and optimized for high temperature (200 degrees C to 400 degrees C) under generally harsh environmental conditions.In this paper it will be demonstrated that high temperature materials can be successfully fabricated into multilayer ceramic capacitors (MLCC). The properties of various capacitors having application range 200 similar to 500 degrees C will be presented. It will include NPO type material with capacitance range 10pF similar to 50nF useful up to 500 degrees C and high Curie temperature Perovskite materials with a capacitance range 10nF similar to 50 mu F at working temperature of 200 similar to 450 degrees C. The properties variations of MLCCs with respect temperature and reliability data will also be presented.

First demonstrated in the 1950's, ferroelectric generators (FEG) have been shown to be versatile compact pulsed-power sources. An FEG works by subjecting a ferroelectric ceramic to a high-pressure shock-wave typically produced by a high-explosive charge. The resulting compression causes the ferroelectric to release the electric charge stored within its crystal structure. Most explosively-driven FEG research has used commercial-off-the-shelf piezoelectric compositions such as lead zirconate-titanate ( Pb(Zr0.52Ti0.48)O3, i.e. PZT ). Although these materials can be used to demonstrate pulsed-power and RF weapons concepts, they do not deliver enough energy to field compact devices.

A new compositional family of relaxor ferroelectrics was investigated based on the high-temperature Bi(Me)O-3-PbTiO3 ferroelectric perovskite family. Compositions were fabricated near an estimated morphotropic phase boundary (MPB) of the xBiScO(3) -yPb(Mg1/3Nb2/3)O-3-zPbTiO(3) (xBS-yPMN-zPT) ternary system exhibiting high-temperature relaxor properties of T-max similar to 250 degrees-350 degrees C and epsilon(max) similar to 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, EA, 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-f while slim loop hysteresis behavior was observed at temperatures T-f < T < T (max). Pyroelectric current measurements were made and integrated to determine macroscopic polarization-temperature dependence, and were in excellent agreement with the hysteresis data. The macroscopic polarization was found to drop off rapidly near the freezing temperature, T-f. At temperatures T > T-max the deviation temperature, T-D, was obtained from Curie-Weiss analysis and found to be similar to 600 degrees C. A comparison of characteristic electrical properties was made between the high-temperature perovskite relaxors and the classical complex lead relaxor compound, Pb(Mg1/3Nb2/3)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 front 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 approximate to 19,000 and tan delta approximate to 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. (c) 2007 Elsevier B.V. All rights reserved.

Explosively driven ferroelectric generators (FEGs) are reliable, compact, high voltage sources that utilize high pressures to liberate charge trapped in the crystal structure of ferroelectric materials. For the active ferroelectric element most FEG designs use commercial lead zirconate-titanate (PZT) compositions designed for either precision actuators or naval sonar transducers. However, the material properties that are important in FEG applications are not the same material properties for which these materials have been designed to maximize. FEG designs utilizing these commercial materials are performance limited by high voltage breakdown, mechanical failure and low energy densities. TRS Technologies inc. has produced a new series of ferroelectric elements designed specifically for FEG applications. HEM Technologies has performed dielectric strength and shock compression experiments on these new materials to evaluate their performance in comparison to existing commercially available materials.

This chapter contains sections titled: Introduction Experimental Procedure Results and Discussion Conclusion Acknowledgement

Recent advances in the areas of high temperature superconductors and low temperature MOSFET devices have opened the door to the possibility of developing highly efficient low-temperature power electronics. The most commonly used high-efficiency capacitors are based on high dielectric constant (K similar to 1000-4000) barium titanate doped to yield and X7R temperature dependence (+/- 15% change in capacitance from -55 degrees C to 125 degrees C); however, below their minimum use temperature the capacitance drops-off quickly leading to a low volumetric efficiency and high temperature coefficient of capacitance (TCC) at cryogenic temperatures.A series of low temperature materials with moderate to high dielectric constants have been specifically developed for low temperature operation (below 80K). The capacitors fall into three main categories: low TCC, high volumetric efficiency, and energy storage. In the low TCC category, co-fired multilayer ceramic capacitors (MLCCs) were fabricated with capacitance values up to 62nF at 30K, TCCs from 0.9 to 2% below 80K, and losses on the order of 0.0001. In the high volumetric efficiency category, dielectrics with permittivities ranging from 1,000 to 30,000 were demonstrated.

In this paper we report the evolution of the polar cluster like behavior with the incorporation of Ti4+ ion in BaZrO3 Ceramics. Dielectric behavior of BaZrxTi(1−x)O3 (x=1.00, 0.95, 0.90, 0.85) ceramics is studied in the temperature range from 300 to 30 K. Polar cluster like behavior becomes more prominent with the increase in content of Ti4+ ion. The dielectric relaxation is analyzed by Vogel–Fulcher relation and Arrhenius law. Frequency dependence of dielectric constant and low loss tangent of these materials can be useful for the potential applications at low temperature.

The bismuth-based perovskite solid solution (100−x)BiScO3−xPbTiO3 (BSPT) was investigated for use at temperatures up to 400°C and above. The high-temperature resistivity, together with dielectric and piezoelectric behaviors of the shear mode for manganese-modified BSPT ceramics near the morphotropic phase boundary composition were studied. The resistivity and time constant were found to be 3×107Ωcm and 0.08s, respectively, at 450°C for modified BSPT66. The dielectric constant Κ11T and dielectric loss were found to be 1112 and 1%, respectively, at room temperature, showing a Curie temperature at 468°C. The electromechanical coupling factor k15 was calculated to be 61%, staying nearly constant up to 440°C, expanding the temperature usage range significantly. The properties indicate that the modified BSPT66 material is a promising candidate for high-temperature shear sensor applications.

There is a growing need for actuator materials that can operate efficiently at extreme temperatures. For example: the James Webb Space Telescope (JWST) requires shape and position control actuators that operate near 30 K (-243/spl deg/C); while NASA's planned Venus mission requires actuators that operate at 460/spl deg/C (733 K). This paper discusses novel piezoelectric single crystal actuators and ultrasonic motors have been developed for use in cryogenic environments as low as 20 K (-253/spl deg/C) and new ceramic piezoelectrics that operate at temperatures as high as 500/spl deg/C (773 K). Various single crystal piezoelectric actuators have been developed including stack actuators and flextensional actuators with strokes up to 250 /spl mu/m and resolutions of >1 nm at temperatures between 20 K and 300 K. A wobbling mode cryomotor has also developed with a stroke of 1 to 10 mm and a resolution of 20 nm in the temperature range of 77 K to 300 K. The cryogenic actuators presented in this paper feature high precision displacement control, high force output, quick response, low power consumption, and are free of magnetic field interference. 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, and spectrometers for remote sensing applications. New actuator materials have also been developed specifically for high-temperature applications. This paper addresses development of this material for an ultrasonic rock drilling-coring-abrading tool to quickly sample Venus surface material for chemical analysis. The key innovation behind this device is a BiScO/sub 3/-PbTiO/sub 3/ based piezoelectric ceramic that has been modified to have high resistivity up to 500/spl deg/C. This material was found to have very good piezoelectric properties to the depoling temperature of 420/spl deg/C, and at 450/spl deg/C it functioned as an electrostrictor with an induced piezoelectric coefficient of /spl sim/450 pC/N under a 7 kV/cm DC bias.