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1

Cylindrical Micro Ultrasonic Motor Utilizing Bulk Lead Zirconate Titanate (PZT)  

Microsoft Academic Search

Ultrasonic motors are expected to be used as microactuatorsbecause of their high torque, low speed and simple construction. Wehave already reported cylindrical-shaped micro ultrasonic motors whichutilized a lead zirconate titanate (PZT) thin film. In this paper, wediscuss a micro ultrasonic motor composed of bulk PZT. The statortransducer had dimensions of 2.4 mm in diameter and 10 mmlength. The maximum revolution

Takeshi Morita; Minoru Kuribayashi Kurosawa; Toshiro Higuchi

1999-01-01

2

Formation and stability of self-assembled monolayers on thin films of lead zirconate titanate (PZT)  

Microsoft Academic Search

Self-assembled monolayers (SAMs) of alkylsiloxanes were formed from hexyltrichlorosilane (HTS) and octadecyltrichlorosilane (OTS) on surfaces of thin films of a complex oxide, lead zirconate titanate (PZT). X-ray photoelectron spectroscopy (XPS) and contact angle measurements confirmed the formation of a thin, uniform organic layer on the surface of the PZT, consistent with the hypothesis that a densely packed organic monolayer is

Rajesh Vaidya; G. P. Lopez; R. J. Simonson; J. Cesarano; D. Dimos

1996-01-01

3

Active micromixer for microfluidic systems using lead-zirconate-titanate (PZT)-generated ultrasonic vibration.  

PubMed

A micromixer using direct ultrasonic vibration is first reported in this paper. The ultrasonic vibration was induced by a bulk lead-zirconate-titanate (PZT; 5 x 4 x 0.2 mm), which was excited by a 48 kHz square wave at 150 V (peak-to-peak). Liquids were mixed in a chamber (6 x 6 x 0.06 mm) with an oscillating diaphragm driven by the PZT. The oscillating diaphragm was in the size of 6 x 6 x 0.15 mm. Ethanol and water were used to test the mixing effectiveness. The laminar flows of ethanol (115 microL/min) and water (100 microL/min) were mixed effectively when the PZT was excited. The entire process was recorded using a video camera. PMID:10634477

Yang, Z; Goto, H; Matsumoto, M; Maeda, R

2000-01-01

4

Stress Control and Ferroelectric Properties of Lead Zirconate Titanate (PZT) Thin Film on Si Substrate with Buffer Layers  

NASA Astrophysics Data System (ADS)

Lead zirconate titanate (PZT) thin films were grown on a Si substrate with an epitaxial relationship by introducing yttria-stabilized zirconia (YSZ), CeO2, and (La,Sr)CoO3 (LSCO) buffer layers. The buffer layers, which facilitated the growth of the epitaxial PZT thin film and controlled the residual stress, were deposited by pulsed laser deposition (PLD). The PZT thin films were fabricated on [A]: LSCO*/CeO2/YSZ/Si and [B]: LSCO*/PZT*/LSCO/CeO2/YSZ/Si by pulsed metalorganic chemical vapor deposition. The respective thicknesses of the LSCO* and PZT* layers were changed to control the residual stress in the PZT thin films. The relationship between residual stress and the ferroelectric properties of the PZT thin films was investigated. Residual tensile stresses in the PZT thin films were maximum in [A] as LSCO* thickness changed. Increasing the PZT* layer thickness at a fixed thickness of LSCO* of 188 nm changed the residual tensile stress in the PZT thin films from 2.92 GPa to 2.67 GPa. Consequently, remanent polarization (2Pr) was increased from 15 ?C/cm2 to 27 ?C/cm2, suggesting that residual stress may be controlled by introducing buffer layers and that ferroelectric properties may be improved.

Fujito, Keisuke; Wakiya, Naoki; Mizutani, Nobuyasu; Shinozaki, Kazuo

2005-09-01

5

Low temperature sintering of lead magnesium nickel niobate zirconate titanate (PMN-PNN-PZT) piezoelectric ceramic, with high performances  

Microsoft Academic Search

Low temperature sintering of quarternary system lead magnesium nickel niobate zirconate titanate (PMN-PNN-PZT) piezoelectric ceramics has been investigated. This ceramic with proper additives could be sintered at about 900°C and exhibited excellent piezoelectric properties: Kp = 0.61–0.65, Qm ? 1000, ?T\\/33\\/?0 = 2300–2800, d33 = 430–465 × 10 C\\/N, tg? ? 50 × 10, ? = 7.9–8.01 g\\/cm. The microstructure

Gui Zhilun; Li Longtu; Lin Hongqing; Zhang Xiaowen

1990-01-01

6

Effects of hydrolysis on metallo-organic solution deposition of PZT (lead zirconate titanate) films  

SciTech Connect

The effects of hydrolysis on the degree of polymerization during metallo-organic solution deposition of lead zirconate titanate (PZT) films have been investigated. The reaction of lead 2-ethylhexanoate, zirconium n-tetrapropoxide, and titanium tetrabutoxide in isopropanol with water were studied using thermogravimetry, specular reflectance Fourier transform infrared spectroscopy (FTIR), and optical and electron microscopy. Films prepared from coating solutions having varying amounts of water exhibited dramatic differences in morphology. The films were spin-coated on platinum coated fused silica substrates and annealed at 525/sup 0/C for 30 minutes. Unhydrolyzed coating solutions and solutions with a mole ratio of water to total metal of 0.5 yielded perovskite films with 0.5 to 5 ..mu..m grains. A mole ratio of 1.5 (the amount of water required to completely hydrolyze the metallo-organics in the solution) formed amorphous, porous films. The stability of the prepolymerized films inhibits crystallization and densification at moderate temperatures.

Lipeles, R.A.; Coleman, D.J.; Leung, M.S.

1986-10-30

7

Effect of multi-coating process on the orientation and microstructure of lead zirconate titanate (PZT) thin films derived by chemical solution deposition  

Microsoft Academic Search

This paper describes the effects of multi-coating processes on the orientation, microstructure and electrical property of lead zirconate titanate (PZT) thick films derived by chemical solution deposition. PZT thick films (>1 ?m in thickness) were deposited by various multi-coating processes, such as layer-by-layer crystallization, seed-layering or single-crystallization. The orientation and microstructure of the thick films were characterized by X-ray diffractometry

T. Kobayashi; M. Ichiki; J. Tsaur; R. Maeda

2005-01-01

8

Dielectric properties of rare earth (Sm and La) substituted lead zirconate titanate (PZT) ceramics  

NASA Astrophysics Data System (ADS)

In the present paper, we are reporting the studies on dielectric properties of Lanthanum (La) and Samarium (Sm) substituted Lead Zirconate Titanate with compositional formula Pb(1.02-x)SmxZr0.55Ti0.45O3 and Pb(1.02-x)LaxZr0.55Ti0.45O3 with x = 0.00, 0.01, 0.02, 0.03. The materials were synthesized by solid state reaction route. XRD analysis shows that all the samples be in single phase with tetragonal structure. Dielectric properties were studied as a function of temperature.

Dipti; Singh, Sangeeta; Juneja, J. K.; Raina, K. K.; Prakash, Chandra

2013-06-01

9

Lead zirconate titanate ceramics  

SciTech Connect

This patent describes a lead zirconate titanate (PZT) piezoelectric ceramic composition which, based on total composition weight, consists essentially of a solid solution of lead zirconate and lead titanate in a PbZrO/sub 3/:PbTiO/sub 3/ ratio from about 0.505:0.495 to about 0.54:0.46; a halide salt selected from the group consisting of fluorides and chlorides of alkali metal and alkaline earth elements and mixtures thereof except for francium and radium in an amount from about 0.5 to 2 weight percent; and an oxide selected from the group consisting of magnesium, barium, scandium, aluminum, lanthanum, praesodynium, neodymium, samarium, and mixtures thereof in an amount from about 0.5 to about 6 weight percent, the relative amount of oxide being from about 1 to about 4 times that of the halide.

Walker, B.E. Jr.

1986-12-02

10

Electrohydrodynamic deposition of nanostructured lead zirconate titanate.  

PubMed

The deposition of a propanol-based lead zirconate titanate (PZT) sol using electrohydrodynamic atomization (EHDA) in the stable cone-jet mode was investigated. The droplets generated were deposited onto a copper substrate as a film, which was investigated using X-ray diffraction and scanning electron microscopy. The PZT film was shown to contain uniform nano-particles of PZT, which maintained their shape on sintering (650 degrees C, 1 hour) while forming the perovskite phase of PZT. PMID:16433420

Sun, D; Rocks, S A; Edirisinghe, M J; Dorey, R A; Wang, Y

2005-11-01

11

Sound velocity variation as function of polarization state in Lead Zirconate Titanate (PZT) Ceramics  

NASA Astrophysics Data System (ADS)

There are several ultrasonic techniques to measure the sound velocity, for example, the pulse-echo method. In such method, the size of transducer used to measure the sound velocity must be in the same order of the sample size. If not, the incompatibility of sizes becomes an error source of the sound velocity measurement. In this work, the Laser Induced Pressure Pulse (LIPP) method is used as ultrasonic method. This method has been very useful for studying the spatial distribution of charges and polarization in dielectrics. We take advantage of the fact that the method allows the sound velocity measurement, to study its variation as function of polarization state in (PZT) ceramics. In a sample with a known thickness e, the sound velocity ? is deduced from the measurement of the transit time T. The sound velocity depends on the elastic constants which in turn they depend on poling conditions. Thus, the variation of the sound velocity is related to the direction and the amplitude of the polarization.

Essolaani, W.; Farhat, N.

2012-02-01

12

Formation of microstructure and ferroelectric domains in lead zirconate titanate (PZT) thin films  

NASA Astrophysics Data System (ADS)

The growth and microstructural development of PZT ferroelectric thin films has been investigated using both processing and theoretical approaches. Typically, excess Pb is added to films to compensate for PbO volatilization during heat treatment. Here, it is shown that the use of stoichiometric precursors with either a PbO atmosphere powder or a PbO overcoat during the crystallization heat treatment are attractive and viable alternative methods for control of film stoichiometry. Using these approaches, single phase perovskite thin films have been fabricated with microstructures and electrical properties (Psbr ˜36 muC/cmsp2 and Esbc ˜45 kV/cm) comparable to those of films using optimized solution chemistries and excess Pb additions. The addition of excess Pb to precursors was shown to increase the nucleation and growth kinetics of the perovskite phase during crytallization. Additionally, it was shown that it often necessary to control the PbO activity of the system during firing despite these Pb additions to fully compensate for volatilization because the processing "window" is narrow. The possible domain patterns are developed for (001) oriented epitaxial rhombohedral (FsbR) and (111) tetragonal (FsbT) oriented perovskite ferroelectric films. The domain patterns form to minimize elastic energy in the film, at the energetic expense of both forming domain boundaries and developing local stresses in the substrate. FsbR domain patterns may develop with either \\{100\\} or \\{101\\} boundaries, where as FsbT have either \\{101\\} or \\{101\\} boundaries. In all cases, the individual domains in the patterns are energetically degenerate and thus equal width lamellar patterns are predicted. The \\{100\\} and \\{101\\} boundary patterns have no normal component of the net polarization whereas the \\{101\\} boundary patterns in both films correspond to the fully poled state. The coherency defect technique is developed for the domain pattern energetics in both sets of films. The coherency defects that are necessary to maintain the epitaxy during the ferroelectric phase transition are considered to be the only sources of elastic strains and stresses (and, correspondingly energy) in the film/substrate system. It is predicted that there is no critical thickness for domain pattern formation in either (001) rhombohedral or (111) tetragonal ferroelectric epitaxial films. Agreement is shown between experimentally observed domain widths and theoretically predicted values. The voltage contrast technique was used to observe domain patterning, including 180sp° boundaries and tiling, in various ferroelectric films. This method is believed to be applied to thin films for the first time here. Because the technique is nondestructive, it allows the domains to be imaged in their equilibrium state.

Lefevre, Matthew James, I.

13

Phase evolution studies of sol-gel derived lead zirconate titanate (PZT) nanopowder using X-ray diffraction and X-ray photoelectron spectroscopy  

NASA Astrophysics Data System (ADS)

We report here the formation of single phase lead zirconate titanate (PZT) nanopowder with composition Pb(Zr0.52Ti0.48)O3 and average crystallite size 12-20 nm, synthesized by sol-gel process. The phase evolution of PZT gel powder, heat treated at temperatures 550, 650 and 800°C was monitored by X-ray diffraction (XRD) and X-ray photo-electron spectroscopy (XPS). The high resolution XPS spectra of Pb4f, Zr3d, Ti2p and O1s show that PZT with pure perovskite structure is obtained at 800°C while at lower temperatures pyrochlore phase co-exists with perovskite phase. The XRD results also support this analysis. We have also identified the pyrochlore phase using XPS by analyzing the corresponding variations in the FWHM values, peak positions and the separation between the spin doublets of Pb, Zr and Ti associated with it. The composition of the final powder obtained with pure perovskite structure is calculated and is close to the designed value.

Sachdeva, Anupama; Kumar, Mahesh; Luthra, Vandna; Tandon, R. P.

2011-07-01

14

Hydrothermal synthesis of vertically aligned lead zirconate titanate nanowire arrays  

NASA Astrophysics Data System (ADS)

A hydrothermal method is employed for the growth of single crystal vertically aligned lead zirconate titanate (PZT) nanowire arrays. The resulting PZT nanowires were grown from a TiO2 film and are shown to be single crystal with growth in the [110] axis. PZT has a coupling coefficient up to two orders of magnitude higher than ZnO, which should provide many opportunities for the creation of active nanodevices and systems.

Lin, Yirong; Liu, Yingtao; Sodano, Henry A.

2009-09-01

15

Lead Zirconate Titanate (LZT) Ceramics.  

National Technical Information Service (NTIS)

A method of producing fully reacted, homogeneous lead zirconate titanate powders including all the technologically important property modifying additives is described. The method involves reacting mixture of powders of the components together with a eutec...

J. H. Rosolowski R. H. Arendt J. W. Szymaszek

1977-01-01

16

Electrooptic Properties of Epitaxial Lead Zirconate Titanate Films on Silicon Substrates  

Microsoft Academic Search

Electrooptic (EO) properties and propagation losses of the lead zirconate titanate (PZT) films grown on silicon (Si) substrates have been investigated. PZT films were prepared on Si substrates by chemical solution method. Refractive index changes and propagation losses of PZT films were evaluated by prism coupling method. A (100)-oriented 8.9-mum-thick epitaxial PZT film grown on a Si substrate with strontium

Kazuaki Kurihara; Masao Kondo; Keisuke Sato; Masatoshi Ishii; Naoki Wakiya; Kazuo Shinozaki

2007-01-01

17

Piezoelectricity in lead zirconate titanate nanowires: A theoretical study  

NASA Astrophysics Data System (ADS)

The piezoelectric coefficients for lead zirconate titanate (PZT) being an order of magnitude higher than the piezoelectric semiconductors, it is expected that this piezoceramic would be very promising for mechanical energy harvesting. This paper presents a systematic evaluation of the piezoelectric potential generated in charge-free PZT nanowires upon application of mechanical strain in different directions. Similar to wurtzite semiconductor nanowires, in case of PZT wires of rocksalt crystal structure, it is found that the stretching modes generate higher potential than the bending mode. However, in spite of high piezoelectric coefficients, the piezoelectric potential generated from these piezoceramic wires is much lower than the semiconductor nanowires because of their high dielectric constant.

Sen, Banani; Stroscio, Michael; Dutta, Mitra

2012-07-01

18

Self-limiting behavior of the grain growth in lead zirconate titanate thin films  

Microsoft Academic Search

During the lateral grain-growth process in lead zirconate titanate (PZT) thin films by selectively nucleated lateral crystallization using PZT seed, it was found that the lateral growth was saturated with the annealing temperature. The saturation of lateral growth was analyzed by the interface energy, which appeared during the crystallization process. The factors affecting the saturation of lateral growth were found

Jang-Sik Lee; Seung-Ki Joo

2002-01-01

19

Laboratory calibration measurements of a piezoelectric lead zirconate titanate cosmic dust detector at low velocities  

Microsoft Academic Search

A cosmic dust monitor for use onboard a spacecraft is currently being developed using a piezoelectric lead zirconate titanate element (PZT). Its characteristics of the PZT sensor is studied by ground-based laboratory impact experiments using hypervelocity particles supplied by a Van de Graaff accelerator. The output signals obtained from the sensor just after the impact appeared to have a waveform

S. Takechi; K. Nogami; T. Miyachi; M. Fujii; N. Hasebe; T. Iwai; S. Sasaki; H. Ohashi; H. Shibata; E. Grün; R. Srama; N. Okada

2009-01-01

20

Dielectrophoretic assembly of lead zirconate titanate microtubes  

NASA Astrophysics Data System (ADS)

Lead zirconate titanate (PZT) microtubes were assembled onto pre-patterned substrates using dielectrophoresis of a colloidal suspension of microtubes dispersed in isopropyl alcohol. High aspect ratio tubes with an outer diameter of 2 ?m and length of about 30 ?m were prepared by vacuum infiltration of mesoporous silicon templates. An interdigitated electrode structure with gap sizes ranging from 2 ?m to 15 ?m was patterned on a silicon substrate via conventional lithography. This allowed a non-uniform alternating electric field to be generated. The influence of the electrode gap along with the effects of the waveform, amplitude and frequency of an applied signal on the dielectrophoretic assembly of PZT microtubes was investigated. A square wave signal of 5 V and 10 Hz was found to be the most effective in assembling the microtubes on a 12 ?m electrode gap. The results show potential for the dielectrophoretic technique in realizing integrated 3D devices using the high aspect ratio piezoelectric tube structures as building blocks. A vacuum infiltration technique was employed to fabricate PZT microtubes. Microtubes were aligned and positioned by dielectrophoresis. A square wave signal of 5 V/10 Hz was the most effective in assembling the tubes.

Koval, V.; Bharadwaja, S. S. N.; Li, M.; Mayer, T. S.; Trolier-McKinstry, S.

2011-12-01

21

Lead zirconate titanate behaviors in an LDMOS  

NASA Astrophysics Data System (ADS)

The behaviors of lead zirconate titanate (PZT) deposited as the dielectric for high-voltage devices are investigated experimentally and theoretically. The devices demonstrate not only high breakdown voltages above 350 V, but also excellent memory behaviors. A drain current—gate voltage (ID—VG) memory window of about 2.2 V is obtained at the sweep voltages of ±10 V for the 350-V laterally diffused metal oxide semiconductor (LDMOS). The retention time of about 270 s is recorded for the LDMOS through a controlled ID—VG measurement. The LDMOS with memory behaviors has potential to be applied in future power conversion circuits to boost the performance of the energy conversion system.

Zhai, Ya-Hong; Li, Wei; Li, Ping; Li, Jun-Hong; Hu, Bin; Huo, Wei-Rong; Fan, Xue; Wang, Gang

2013-07-01

22

Ultrahigh resolution of lead zirconate titanate 30/70 domains as imaged by piezoforce microscopy  

NASA Astrophysics Data System (ADS)

Piezoforce microscopy (PFM) has been used to determine the domain structure of lead zirconate titanate (PZT) (30/70) on an indium tin oxide (ITO)/glass substrate with a TiO2 boundary layer. The PZT nucleates into the perovskite form in a random crystallographic manner, which leads to a random domain structure in the final film. Using PFM it has been possible to visualize the domain structure of the PZT and determine that the domain structure has features as fine as 8 nm herringbone patterns. The possible impact of these structures for future devices utilizing nanoscale features of PZT and especially FeRAM developments is highlighted.

Dunn, S.; Shaw, C. P.; Huang, Z.; Whatmore, R. W.

2002-08-01

23

Measurement of incident position of hypervelocity particles on piezoelectric lead zirconate titanate detector  

SciTech Connect

A cosmic dust detector for use onboard a satellite is currently being developed by using piezoelectric lead zirconate titanate (PZT). The characteristics of the PZT detector have been studied by bombarding it with hypervelocity iron (Fe) particles supplied by a Van de Graaff accelerator. One central electrode and four peripheral electrodes were placed on the front surface of the PZT detector to measure the impact positions of the incident Fe particles. It was demonstrated that the point of impact on the PZT detector could be identified by using information on the time at which the first peak of the output signal obtained from each electrode appeared.

Takechi, Seiji; Onishi, Toshiyuki; Minami, Shigeyuki [Graduate School of Engineering, Osaka City University, Osaka 558-8585 (Japan); Miyachi, Takashi; Fujii, Masayuki; Hasebe, Nobuyuki [Advanced Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555 (Japan); Nogami, Ken-ichi [Department of Physics, Dokkyo University School of Medicine, Tochigi 321-0293 (Japan); Ohashi, Hideo [Faculty of Marine Science, Tokyo University of Marine Science and Technology, Tokyo 108-8477 (Japan); Sasaki, Sho [National Astronomical Observatory of Japan, Iwate 023-0861 (Japan); Shibata, Hiromi [Graduate School of Engineering, Kyoto University, Kyoto 606-8501 (Japan); Iwai, Takeo [Research Center for Nuclear Science and Technology, The University of Tokyo, Ibaraki 319-1106 (Japan); Gruen, Eberhard; Srama, Ralf [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Okada, Nagaya [Honda Electronics Co., Ltd., Aichi 441-3193 (Japan)

2008-04-15

24

Measurement of incident position of hypervelocity particles on piezoelectric lead zirconate titanate detector.  

PubMed

A cosmic dust detector for use onboard a satellite is currently being developed by using piezoelectric lead zirconate titanate (PZT). The characteristics of the PZT detector have been studied by bombarding it with hypervelocity iron (Fe) particles supplied by a Van de Graaff accelerator. One central electrode and four peripheral electrodes were placed on the front surface of the PZT detector to measure the impact positions of the incident Fe particles. It was demonstrated that the point of impact on the PZT detector could be identified by using information on the time at which the first peak of the output signal obtained from each electrode appeared. PMID:18447524

Takechi, Seiji; Onishi, Toshiyuki; Minami, Shigeyuki; Miyachi, Takashi; Fujii, Masayuki; Hasebe, Nobuyuki; Nogami, Ken-ichi; Ohashi, Hideo; Sasaki, Sho; Shibata, Hiromi; Iwai, Takeo; Grün, Eberhard; Srama, Ralf; Okada, Nagaya

2008-04-01

25

Characterization of lead zirconate titanate ceramics for use in miniature high-frequency (20-80 MHz) transducers  

Microsoft Academic Search

The material properties of lead zirconate titanate (PZT) ceramics for operation in the thickness mode at frequencies as high as 80 MHz are reported. Each of the ceramics tested showed a reduction in k t with increasing frequency. In a fine-grained PZT, values of kt as high as 0.44 were measured at 80 MHz. The effects of grain size were

F. Stuart Foster; Linda K. Ryan; Daniel H. Turnbull

1991-01-01

26

A new perspective of high Zr-content lead zirconate titanate  

Microsoft Academic Search

Lead zirconate titanate (PZT) ceramics with Zr\\/Ti ratios between 95\\/5 and 55\\/45 have been examined by transmission electron microscopy (TEM) and dielectric spectroscopy. It is believed that in the high Zr-content end of the PZT phase diagram that the relative phase stability is directly related to a coupling of the polarization to various oxygen octahedral rotational systems. The transformation between

Dwight Viehland; Jie-Fang Li; X. H. Dai; Z. Xu

1996-01-01

27

Structural and property studies of high Zr-content lead zirconate titanate  

Microsoft Academic Search

Lead zirconate titanate (PZT) ceramics with ZrTi ratios between 955 and 5545 have been examined by transmission electron microscopy (TEM), dielectric spectroscopy, and Sawyer-Tower polarization measurements. It is believed that in the high Zr-content end of PZT phase diagram, that the relative phase stability is directly related to a coupling of the polarization to various oxygen octahedral rotational systems. The

Dwight Viehland; Jie-Fang Li; Xunhu Dai; Z. Xu

1996-01-01

28

Effects of electric field and biaxial flexure on the failure of poled lead zirconate titanate  

Microsoft Academic Search

Reliable design of lead zirconate titanate (PZT) piezo stack actuators demands that several issues, including electromechanical coupling and ceramic strength-size scaling, be scrutinized. This study addresses those through the use of ball-on-ring (BoR) biaxial flexure strength tests of a PZT piezoelectric material that is concurrently subjected to an electric field. The Weibull strength distributions and fracture surfaces were examined. The

Hong Wang; Andrew A Wereszczak

2008-01-01

29

Response of Piezoelectric Lead-Zirconate-Titanate to Hypervelocity Silver Particles  

Microsoft Academic Search

A lead-zirconate-titanate (PZT) element was studied by bombarding silver particles in the mass range from 1 to 100 pg, and the velocity from 2 to 6 km\\/s. Output signals were uniquely identified on impact and characterized by Fourier analysis. It was found that incident energies above 100 nJ were uniquely determined by a single PZT element. We discussed its potential

Takashi Miyachi; Nobuyuki Hasebe; Hiroshi Ito; Takahiro Masumura; Hiroyuki Okada; Hideki Yoshioka; Masato Higuchi; Tadayoshi Matsuyama; Ken-ichi Nogami; Takeo Iwai; Hiromi Shibata; Yoshimi Hamabe; Sho Sasaki; Seiji Sugita; Hideo Ohashi; Sunao Hasegawa; Hajime Yano; Masanori Sato; Tonshaku Tou

2003-01-01

30

Ferroelectric\\/ferroelastic behavior and piezoelectric response of lead zirconate titanate thin films under nanoindentation  

Microsoft Academic Search

The electromechanical response of pure lead zirconate titanate (PZT) and Mn-doped PZT thin ferroelectric films under nanoindentation forces of up to 500 mN was investigated. The stress-induced current transients were measured as a function of the externally applied load on films of different thicknesses using a spherical WC–Co cermet indenter of 500 ?m nominal radius. It was found that the

V. Koval; M. J. Reece; A. J. Bushby

2005-01-01

31

Ferroelectric\\/ferroelastic behavior and piezoelectric response of lead zirconate titanate thin films under nanoindentation  

Microsoft Academic Search

The electromechanical response of pure lead zirconate titanate (PZT) and Mn-doped PZT thin ferroelectric films under nanoindentation forces of up to 500 mN was investigated. The stress-induced current transients were measured as a function of the externally applied load on films of different thicknesses using a spherical WC-Co cermet indenter of 500 mum nominal radius. It was found that the

V. Koval; M. J. Reece; A. J. Bushby

2005-01-01

32

Fabrication of Lead Zirconate Titanate Films by Inkjet Printing  

NASA Astrophysics Data System (ADS)

In this study, a finely patterned lead zirconate titanate (PZT) film is fabricated by a combination of inkjet printing (IJP), chemical solution deposition (CSD), and surface energy controlling technology. We used patterned multilayer lower electrodes, which easily enable high surface energy contrast on the lower electrode area and achieved high accuracy patterning in the inkjet deposition process. The PZT film, which can be used as an actuator, has 2 ?m thickness after iterating the set of surface treatment, inkjet deposition, and baking. This film has a dielectric constant (\\varepsilonr) of 1700, loss tangent (\\tan?) of 0.05, remanent polarization (Pr) of 10 ?C/cm2, and coercive field (Ec) of 23 kV/cm. Piezoelectric coefficient d31 estimated from a displacement of the membrane was determined to be 77 pm/V. These results suggest that this method is a candidate for piezo microelectromechanical system (MEMS) fabrication.

Machida, Osamu; Shimofuku, Akira; Tashiro, Ryo; Takeuchi, Atsushi; Akiyama, Yoshikazu; Ohta, Eiichi

2012-09-01

33

Thickness dependence of the poling and current-voltage characteristics of paint films made up of lead zirconate titanate ceramic powder and epoxy resin  

Microsoft Academic Search

A specially prepared paint made up of lead zirconate titanate (PZT) ceramic powder and epoxy resin was coated on an aluminum plate and was cured at room temperature, thus forming the paint film of 25–300 ?m thickness with a PZT volume fraction of 53%. The paint film was then poled at room temperature, and the poling behavior was determined by

Shigenori Egusa; Naozumi Iwasawa

1995-01-01

34

A Yttrium Iron Garnet-Lead Zirconate Titanate Phase Shifter  

NASA Astrophysics Data System (ADS)

Tunable microwave phase shifters are of interest for miniature oscillators and phased array antenna systems. Traditional ferrite phase shifters use magnetic tuning systems that are slow, demand high power, and are not miniature in size. Here we discuss the design, fabrication and characterization of a novel electric field tunable phase shifter based on a yttrium iron garnet (YIG) -- lead zirconate titanate (PZT) bilayer. The electrical control of the phase shift is realized through magnetoelectric (ME) interaction. The phase shifter consisted of a microstrip transmission line with stubs of ?/8 and 3?/8 lengths for generating circularly polarized microwave magnetic field in the YIG-PZT resonator. The ME resonator was made from 124 micron thick (100) YIG film on GGG and 0.5 mm thickness PZT with electrodes. The operating frequency of the phase shifter was set by applying appropriate bias magnetic field. The phase shift vs. electric field E characteristics was linear or quadratic in E, depending on the operating frequency. The maximum phase shift was 180 deg. and showed an insertion loss of 1.5-2.0 dB at 5 GHz and 3-4 dB at the frequency 10 GHz. The ME phase shifter is capable of rapid tuning, miniature in size and dissipates practically zero power. -- The work was supported by grants from ONR, ARO and NSF.

Srinivasan, G.; Tatarenko, A. S.; Bichurin, M. I.

2006-03-01

35

Simulation and calculation of the piezoelectric modulus of a lead zirconate-titanate thin film in a test microstructure  

SciTech Connect

Results of simulation of stresses in the test structure of a silicon beam and analytical calculation of piezoelectric modulus d{sub 31} of a lead zirconate-titanate (PZT) thin film arranged in the region of an elastic element are presented. The characteristics of the sensitive element of acceleration are calculated based on a PZT thin film with an inertial mass made of silicon.

Amelichev, V. V., E-mail: V.Amelichev@tcen.ru [Moscow State Institute of Electronic Engineering, NPK Technological Center (Russian Federation); Saikin, D. A.; Roshchin, V. M.; Silibin, M. V. [Moscow State Institute of Electronic Engineering (Technical University) (Russian Federation)

2010-12-15

36

Intrinsic and Extrinsic Size Effects in Fine-Grained Morphotropic-Phase-Boundary Lead Zirconate Titanate Ceramics  

Microsoft Academic Search

The processing, electromechanical properties, and micro- structure of lead zirconate titanate (PZT) ceramics over the grain-size range of 0.1-10 µm were studied. Using measure- ments over a large temperature range (15-600 K), the rela- tive role of extrinsic contribution (i.e., domain-wall motion) was deduced to be influenced strongly by the grain size, particularly for donor-doped PZT. Analytical transmission electron microscopy

Clive A. Randall; Namchul Kim; John-Paul Kucera; Wenwu Cao; Thomas R. Shrout

2005-01-01

37

Constriction of the polarization by incoherent oxygen octahedral tilting in rhombohedral-structured lead zirconate titanate  

Microsoft Academic Search

Double hysteresis loops have been observed in ferroelectric lead zirconate titanate ceramics with a Zr\\/Ti ratio of 65\\/35 (PZT 65\\/35). In addition, dielectric dispersion was found near 50 °C, corresponding to the high-temperature to low-temperature rhombohedral ferroelectric [FER(HT)-FER(LT)] transformation. Structurally this transformation is an oxygen octahedra tilting along the ?111?. It is proposed that an inability of the oxygen octahedra

Xunhu Dai; Z. Xu; Jie-Fang Li; Dwight Viehland

1995-01-01

38

Nonlinearity and scaling behavior in a soft lead zirconate titanate piezoceramic  

Microsoft Academic Search

Lead oxide-based ferroelectrics, represented by lead zirconate titanate [Pb(Zr,Ti)O3] or PZT), are the most widely used materials for piezoelectric actuators, sensors, and transducers due to their excellent piezoelectric properties. Most of these piezoelectric materials are employed under a variety of strains (stress, electrical field, and temperature). It would thus be interesting to predict their behaviors under different excitations without having

Abdelowahed Hajjaji; Daniel Guyomar; Samira Touhtouh; Sebastien Pruvost; Yahia Boughaleb; Mohamed Rguiti; Christian Courtois; Anne Leriche; Khalil Benkhouja

2010-01-01

39

Detection of high-energy heavy ions using piezoelectric lead zirconate titanate  

SciTech Connect

The characteristics of a radiation detector fabricated with stacks of piezoelectric lead zirconate titanate (PZT) elements were studied by irradiating it with a 400 MeV/n xenon (Xe) beam for various beam pulse durations. This detector is referred to as the multilayered detector (MD). To understand the production mechanism behind the output voltage obtained from the MD, measurement of the spatial distribution of the output signals generated in the MD was attempted. It was found that the amplitude observed was dependent on the number of Xe ions per unit time and the amount of ionization loss energy of Xe ions in PZT.

Takechi, Seiji; Morinaga, Shin-ya; Kurozumi, Atsuma [Graduate School of Engineering, Osaka City University, Osaka 558-8585 (Japan); Miyachi, Takashi; Fujii, Masayuki; Hasebe, Nobuyuki [Advanced Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555 (Japan); Shibata, Hiromi [Graduate School of Engineering, Kyoto University, Kyoto 606-8501 (Japan); Murakami, Takeshi; Uchihori, Yukio [National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Okada, Nagaya [Honda Electronics Co., Ltd., Aichi 441-3193 (Japan)

2009-04-15

40

Position-Dependent Behavior of Piezoelectric Lead--Zirconate--Titanate Cosmic Dust Detector  

NASA Astrophysics Data System (ADS)

A possible position dependence of the signal amplitudes generated by a piezoelectric lead--zirconate--titanate (PZT) detector was studied by bombarding the PZT element with hypervelocity microparticles. The detector was equipped with a set of asymmetrically arranged electrodes. The characteristic features of the element were analyzed using the amplitudes of the fundamental resonant component caused by collisions. As a result, the sensitivity of the element measured with direct collisions onto the collector was found to be one order of magnitude greater than that in the external area of the collector.

Hattori, Maki; Kobayashi, Masanori; Miyachi, Takashi; Takechi, Seiji; Okudaira, Osamu; Iwai, Takeo; Sugita, Seiji

2012-09-01

41

Niobium doped lead zirconate titanate films for infrared sensor application  

NASA Astrophysics Data System (ADS)

Nb-doped lead zirconate titanate with formula Pb1-x/2 Nbx(Zr0.2Ti0.8)1-xO 3 (x=0, 0.01, 0.02, 0.03, 0.04, and abbreviated as PNZT) films with two thicknesses: one of approximately 200 nm and the other of 1 mum, were grown on platinized silicon (Pt/TiOx/SiO2/Si) substrates using the method of chemical solution deposition. These chemical precursors were prepared in-house, and through careful control of the processing procedures high quality films were grown. All the films exhibit highly preferred (111) orientation without any presence of the impurity phase. We systematically investigated the Nb doping effect on the electrical properties of PZT films. Results indicate that Nb belongs to a class of soft dopants for lead zirconate titanate films, and as a result it increases the ferroelectric polarization, pyroelectric coefficient, dielectric constant and tan delta loss. In the capacitors with the configuration of Pt/PNZT/Pt, the leakage current at low electric fields is dominated by the interface-controlled Schottky emission, whereas bulk-controlled Frenkel-Poole emission dominates at high electric fields. Nb-doping up to 2 atomic % can remarkably suppress the Frenkel-Poole emission process. The suppression of mobile oxygen vacancies by Nb donor dopants lowered the leakage current and increases the domain wall mobility. Study also shows that 1% Nb doped PZT films exhibit the highest pyroelectric coefficient, figure of merit and voltage response among all the samples. Therefore these films with such superior properties are potential candidates for applications, especially for fabrication of uncooled pyroelectric IR sensors with better performance.

Han, Hui

42

Effect of surface modification of lead zirconate titanate particles on the properties of piezoelectric composite sensors  

NASA Astrophysics Data System (ADS)

Piezoelectric composite sensors which consist of a ferroelectric ceramic phase and a polymer binder have been the center of interest for offering a distributed sensing mechanism in many industrial applications. This study investigates the effect of PZT surface modification on the mechanical and piezoelectric properties of PZT/epoxy composite sensors. Lead zirconate titanate ceramic powder (PZT-5H) was surface modified to prepare a high PZT content (0-3) piezoelectric composite sensor. Functional groups of the modifiers grafted onto the PZT particle surface served as a bridge into the epoxy matrix, thus creating strong bonds between the matrix and PZT particles. This noticeably improved the dispersion of the PZT phase, allowing the use of large fractions of piezoactive component in the composite. It is demonstrated that the produced piezo-film shows an enhanced poling behavior in that it can be poled with lower voltages under reduced poling times. This is caused by greater levels of microstructural homogeneity in the modified films as well as alteration of interfacial charge characteristics using modifiers' functional groups.

Saber, Nasser; Ma, Jun; Hsu, Hung-Yao; Lee, Sang-Heon; Marney, Donavan

2013-08-01

43

Notes of the recent structural studies on lead zirconate titanate.  

PubMed

Atomic scale structure has a central importance for the understanding of functional properties of ferroelectrics. The X-ray and neutron diffraction studies used for the average symmetry determination of lead zirconate titanate [Pb(ZrxTi(1- x))O3, PZT] ceramics and powders are reviewed. The results obtained through two frequently used local probes, transmission electron microscopy (TEM) combined with electron diffraction (ED) and Raman scattering measurements, are summarized. On the basis of these studies, structural trends as a function of composition x and temperature are outlined. There are two distinguished intrinsic structural features, (i) lead-ion shifts and (ii) local structural distortions related to different B cations and the spatial composition variation of x, which have a pronounced effect on the functional properties of PZT. Particular attention is paid to the morphotropic phase boundary (MPB) compositions for which a large number of different structural models have been proposed. Earlier symmetry considerations show that the monoclinic phase cannot serve as a continuous bridge between tetragonal and rhombohedral phases. This suggests that the two-phase coexistence has an important role for the piezoelectric properties. Near the MPB, the extrinsic contribution to piezoelectricity includes pressure (or electric-field)-induced changes in phase fractions and domain wall motion. It was recently shown that the domain contribution is crucial for the electromechanical properties of PZT in the vicinity of the MPB. The dependence of domain widths on crystal size and shape should also be properly accounted for when TEM/ED measurements complement X-ray and/or neutron diffraction experiments. The structure-piezoelectric property relations are summarized. PMID:18433161

Frantti, J

2008-04-24

44

Fabrication of lead zirconate titanate actuator via suspension polymerization casting  

NASA Astrophysics Data System (ADS)

The research presented herein has focused on the fabrication of a lead zirconate titanate (PZT) telescopic actuator from Suspension Polymerization Casting (SPC). Two systems were studied: an acrylamide-based hydrogel, and an acrylate-based nonaqueous system. Analytical tools such as thermomechanical analysis (TMA), differential scanning calorimetry (DSC), chemorheology, thermogravimetric analysis (TGA), and differential thermal analysis (DTA) were used to investigate the polymerization and burnout processes. The acrylamide hydrogel polymerization casting process used hydroxymethyl acrylamide (HMAM) monofunctional monomer with methylenebisacrylamide (MBAM) difunctional monomer, or used methacrylamide (MAM) as monofunctional monomer. High solid loading PZT slurries with low viscosities were obtained by optimizing the amounts of dispersant and the PZT powders. The overall activation energy of gelation was calculated to be 60--76 kJ/mol for the monomer solution, this energy was increased to 91 kJ/mol with the addition of PZT powder. The results show that the PZT powder has a retardation effect on gelation. Although several PZT tubes were made using the acrylamide-based system, the demolding and drying difficulties made this process unsuitable for building internal structures, such as the telescopic actuator. The acrylate-based system was used successfully to build telescopic actuator. Efforts were made to study the influence of composition and experimental conditions on the polymerization process. Temperature was found to have the largest impact on polymerization. To adjust the polymerization temperature and time, initiator and/or catalyst were used. PZT powder has a catalytic effect on the polymerization process. Compared with acrylamide systems, acrylate provided a strong polymer network to support the ceramic green body. This high strength is beneficial for the demolding process, but it can easily cause cracks during the burnout process. To solve the burnout issue, non-reactive decalin was used as a solvent to lower the stress inside the green body. The addition of decalin has no large impact on the polymerization process. With 15 wt% decalin in the monomer solution, the burnout process was successfully solved. The burnout process was monitored by TGA/DTA and TMA. A 51 vol% PZT filled acrylate slurry was cast into a mold made by Stereolithography (SLA), and after curing, the telescopic actuator was removed from the mold. This indirect SLA method provides an efficient way to build ceramic parts. PZT samples were sintered at 1275°C for 4 hours, with density over 98%. SEM analysis showed the sample made by SPC has a uniform microstructure, which may be beneficial to the electric properties. The sample made by polymerization has a d33 value about 680 pm/V, which is better than the literature value (580 pm/V). The electric tests showed this telescopic actuator produced a maximum deflection of 24.7 mum at 250 kV/m, in line with theoretical calculations. Compared with actuators made by other methods, the actuator made by SPC provides a comparable structural factor (187.5). The distortion in actuators is caused by fabrication and sintering.

Miao, Weiguo

2000-10-01

45

Estimating the impact parameters of cosmic dust particles using a piezoelectric lead zirconate titanate detector  

NASA Astrophysics Data System (ADS)

A cosmic dust detector for installation on a satellite is currently being developed using piezoelectric lead zirconate titanate (PZT), which can possess both functions of the collector and the transducer. The characteristics of the PZT detector have been studied by bombarding it with hypervelocity particles supplied by a Van de Graaff accelerator. The front surface of the detector used in this study was covered with a white paint to reduce any increase in the temperature due to the solar radiation. There was a linear relationship between the rise time of the signal produced by the detector and the particle's velocities, which were above 10 km/s on impact. This implies that individual particle velocities on impact can be inferred through the empirical formula derived from the data obtained from the PZT detector.

Takechi, S.; Miyachi, T.; Fujii, M.; Hasebe, N.; Nogami, K.; Ohashi, H.; Sasaki, S.; Shibata, H.; Iwai, T.; Grün, E.; Srama, R.; Okada, N.

2009-02-01

46

Effect of (Mn, F) and (Mg, F) co-doping on dielectric and piezoelectric properties of lead zirconate titanate ceramics  

NASA Astrophysics Data System (ADS)

The influence of (Mn, F) and (Mg, F) dopants on the piezoelectric properties of lead zirconate titanate (PZT) ceramic compositions close to the morphotropic phase boundary is investigated. PZT ceramics are prepared by a chemical route based on co-precipitation of oxalates and hydroxides. The acceptor is incorporated into the B site of the materials and the fluorine ion is introduced into anionic sites. The d33 coefficient, the mechanical quality factor Qm and other properties are measured. Scanning electron microscopy is used to determine the grain size of the materials. Electron spin resonance is used to determine the valency state of Mn in fluorinated PZT ceramics. In Mn doped PZT, the introduction of a fluorine ion makes the poling process easier and increases the piezoelectric coefficients whereas the fluorination of Mg doped PZT constantly leads to hard materials with a lower piezoelectric response. This study shows that (Mn, F) co-doping produces semihard materials with high piezoelectric coefficients.

Boucher, E.; Guyomar, D.; Lebrun, L.; Guiffard, B.; Grange, G.

2002-11-01

47

Dust detector using piezoelectric lead zirconate titanate with current-to-voltage converting amplifier for functional advancement  

NASA Astrophysics Data System (ADS)

This paper describes the concept of a dust monitor using lead zirconate titanate (PZT) ceramics with a large detection area. Its potential as a dust detector is experimentally demonstrated. The dust monitor has a small volume compared to an impact ionization detector with the same detection area, due to the PZT sensor. The PZT sensor, as a traditional device for the in-situ observation of hypervelocity dust particles, has been used for momentum measurement. The hypervelocity impact signals of PZT sensors are typically read by charge-sensitive amplifiers. Instead, we suggest a new method that a current-to-voltage converting amplifier is useful for interpreting the impact signal of a PZT sensor arising from dust particles down to 0.5 ?m in radius. We propose that datasets of dust impacts can be obtained with a higher statistical accuracy, if the new method is applied to instruments on forthcoming interplanetary-space-cruising spacecrafts.

Kobayashi, M.; Miyachi, T.; Hattori, M.; Sugita, S.; Takechi, S.; Okada, N.

2013-03-01

48

Effects of deposition temperature and seed layer on the optical properties of lead zirconate titanate films  

NASA Astrophysics Data System (ADS)

Lead zirconate titanate (PZT) films were deposited on indium tin oxide coated Corning 7059 glass by rf magnetron sputtering at the temperatures ranging from room temperature to 500 degC. The crack-free PZT films with pure perovskite phase could be successfully fabricated through postannealing at 650 degC for 10 min. The films deposited at 400 degC and subsequently postannealed at 650 degC showed the best optical properties with a linear electro-optic coefficient of 80 pm/V and a propagation loss of 2 dB/cm. It was found from our study on the change of crystalline orientation with film thickness that the 50 nm thick PZT thin film annealed at 650 degC exhibited (100) preferred orientation. Using this thin film as a seed layer, we could fabricate PZT films with (100) preferred orientation that showed higher remnant polarization (2Pr=46 muC/cm2) and dielectric constant (epsilon=1400) compared with randomly oriented films. This highly oriented PZT film also showed an excellent linear electro-optic coefficient of 109 pm/V that is comparable with the value of the PZT film epitaxially grown on the single crystal substrate. copyright 2002 American Vacuum Society.

Kang, Hee-Soo; Lee, Won-Jong

2002-07-01

49

Effects of Electric Field and Biaxial Flexure on the Failure of Poled Lead Zirconate Titanate  

SciTech Connect

Reliable design of lead zirconate titanate (PZT) piezo stack actuators demands that a number of issues, including electromechanical coupling and ceramic strength-size scaling, be scrutinized. This study addresses those through the use of ball-on-ring (BoR) biaxial flexure strength tests of a PZT piezoelectric material that is concurrently subjected to an electric field. The Weibull strength distributions and fracture surfaces were examined. The mechanical failures were further analyzed in terms of internal stress, energy release rate, and domain-switching toughening. Both the sign and the magnitude of an electric field had a significant effect on the strength of poled PZT within the tested range. A surface flaw type with a depth of ~18 m was identified to be the strength limiter and responsible for the failure of the tested PZT under both mechanical and electromechanical loadings. With ~0.74 in the absence of electric field, the fracture toughness of the poled PZT was affected by an applied electric field just as the strength was affected. These results and observations have the potential to serve probabilistic reliability analysis and design optimization of multilayer PZT piezo actuators.

Wang, Hong [ORNL; Wereszczak, Andrew A [ORNL

2008-01-01

50

Effects of electric field and biaxial flexure on the failure of poled lead zirconate titanate.  

PubMed

Reliable design of lead zirconate titanate (PZT) piezo stack actuators demands that several issues, including electromechanical coupling and ceramic strength-size scaling, be scrutinized. This study addresses those through the use of ball-on-ring (BoR) biaxial flexure strength tests of a PZT piezoelectric material that is concurrently subjected to an electric field. The Weibull strength distributions and fracture surfaces were examined. The mechanical failures were further analyzed in terms of internal stress, energy release rate, and domain-switching toughening. Both the sign and the magnitude of an electric field had a significant effect on the strength of poled PZT within the tested range. A surface flaw type with an average depth of around 18 microm was identified to be the strength limiter and responsible for the failure of the tested PZT under both mechanical and electromechanical loadings. With a value of 0.74 MPa.m(1/2) in the absence of electric field, the fracture toughness of the poled PZT was affected by an applied electric field just as the strength was affected. These results and observations have the potential to serve probabilistic reliability analysis and design optimization of multilayer PZT piezo actuators. PMID:19126481

Wang, Hong; Wereszczak, Andrew A

2008-12-01

51

Vibration Velocity Limitation of Transducer Using Titanium-Based Hydrothermal Lead Zirconate Titanate Thick Film  

NASA Astrophysics Data System (ADS)

High-intensity vibration operation of a titanium based lead zirconate titanate (PZT) thick film longitudinal vibrator fabricated using a hydrothermal method is described in this paper. Higher limitation of vibration velocity is very important for high output power actuators. For sensors, linearity of the frequency response is an important factor. To investigate the performance of the PZT film material, we changed the deposition process of the hydrothermal method and increased the thickness of the PZT film. As a result, the maximum vibration velocity of the longitudinal vibrator was 2.5 m/s (0 to peak value). This value was almost 3-fold that of bulk PZT material. The vibration velocity was limited by the value of maximum stress. The maximum stress of the hydrothermal PZT transducer was larger than that of the bulk PZT transducer. At such high-intensity vibration of over 2 m/s or driving voltage of 150 Vp-p, the frequency response curves were not linear and the jumping phenomenon was observed.

Kanda, Takefumi; Kobayashi, Yutaka; Kurosawa, Minoru Kuribayashi; Higuchi, Toshiro

2003-05-01

52

Effect of manganese doping on the size effect of lead zirconate titanate thin films and the extrinsic nature of 'dead layers'  

Microsoft Academic Search

We have investigated the size effect in lead zirconate titanate (PZT) thin films with a range of manganese (Mn) doping concentrations. We found that the dynamic size effect in the conventional Pt\\/PZT\\/Pt thin-film capacitors could be systematically reduced and almost completely eliminated by increasing Mn doping concentration. The interfacial layer at the electrode-film interface appears to disappear almost entirely for

X. J. Lou; J. Wang

2010-01-01

53

Development of a stress sensor based on the piezoelectric lead zirconate titanate for impact stress measurement  

NASA Astrophysics Data System (ADS)

The measurement of stress of concrete structures under impact loading and other strong dynamic loadings is crucial for the monitoring of health and damage detection. Due to its main advantages including availability, extremely high rigidity, high natural frequency, wide measuring range, high stability, high reproducibility, high linearity and wide operating temperature range, piezoelectric (Lead Zirconate Titanate, PZT) ceramic materials has been a widely used smart material for both sensing and actuation for monitoring and control in engineering structures. In this paper, a kind of stress sensor based on piezoelectric ceramics for impact stress measuring of concrete structures is developed. Because the PZT is fragile, in order to employ it for the health monitoring of concrete structures, special handling and treatment should be taken to protect the PZT and to make it survive and work properly in concrete. The commercially available PZT patch with lead wires is first applied with an insulation coating to prevent water and moisture damage, and then is packaged by jacketing it by two small precasted cylinder concrete blocks with enough strength to form a smart aggregate (SA). The employed PZT patch has a dimension of 10mm x 10mm x 0.3mm. In order to calibrate the PZT based stress sensor for impact stress measuring, a dropping hammer was designed and calibration test on the sensitivity of the proposed transducer was carried out with an industry charge amplifier. The voltage output of the stress sensor and the impact force under different free falling heights and impact mass were recorded with a high sampling rate data acquisition system. Based on the test measurements, the sensibility of the PZT based stress sensor was determined. Results show that the output of the PZT based stress sensor is proportional to the stress level and the repeatability of the measurement is very good. The self-made piezoelectric stress sensor can be easily embedded in concrete and provide reliable stress sensing under dynamic loadings.

Liu, Yiming; Xu, Bin; Li, Lifei; Li, Bing

2011-11-01

54

Determination of optimal experimental conditions for the preparation of lead zirconate titanate via sol-precipitate process by applying statistical methods  

Microsoft Academic Search

A fractional factorial design was implemented to optimize the experimental conditions for the preparation of lead zirconate titanate (PZT) from acetate precursors. The effects of such preparatory conditions as the molar ratio of acetic acid to metal alkoxide, the water to alkoxide ratio, the pH value, reaction temperature and the stirring speed, were systematically studied by using a Taguchi orthogonal

Wein-Duo Yang; Kun-Ming Hung; Ching-Shieh Hsieh

2002-01-01

55

Fracture mechanisms in ferroelectric-ferroelastic lead zirconate titanate (Zr:Ti = 0. 54:0. 46) ceramics  

Microsoft Academic Search

Fracture toughness, {ital K}{sub IC}, of a single-phase commercial lead zirconate titanate (PZT) ceramic of tetragonal structure was measured using the single edge notched beam method above and below the Curie temperature. Domain switching (poling) under electrical and mechanical loading was examined using x-ray diffraction. Surface grinding, electrical poling, and mechanical poling caused crystallographic texture. Similar texture, indicative of domain

Karun Mehta; Anil V. Virkar

1990-01-01

56

Lead zirconate titanate-nickel zink ferrite thick-film composites: obtaining by the screen printing technique and magnetoelectric properties  

NASA Astrophysics Data System (ADS)

Layered thick-film composites containing one lead zirconate titanate (PZT) layer, one nickel zinc ferrite (NZF) layer, two PZT-NZF layers, or three PZT-NZF-PZT layers each 40-50 ?m thick are prepared. The layers are applied by screen printing on a ceramic aluminum oxide substrate with a preformed contact (conducting) layer. The dielectric properties of the composites are studied in the temperature interval 80-900 K and the frequency interval 25 Hz-1 MHz. Polarized samples exhibit piezoelectric, pyroelectric, and magnetoelectric effects. In tangentially magnetized two- and three-layer composites, the magnetoelectric conversion factor equals 57 kV/(m T) at low frequencies and reaches 2000 kV/(m T) at the mechanical resonance frequency.

Bush, A. A.; Shkuratov, V. Ya.; Chernykh, I. A.; Fetisov, Y. K.

2010-03-01

57

Piezoelectric Properties of Polycrystalline Lead Titanate Zirconate Compositions  

Microsoft Academic Search

Detailed data are given for the piezoelectric, elastic, and dielectric properties of lead titanate zirconate ceramic compositions near the rhombohedral-tetragonal phase boundary. These compositions have markedly higher electromechanical coupling factors, remanent ferroelectric charge, and coercive field, than ceramic barium titanate. Another interesting feature is a pronounced change in the free permittivity ¿33T by the poling process; this change is in

D. A. Berlincourt; C. Cmolik; H. Jaffe

1960-01-01

58

Hydrogen diffusion in Lead Zirconate Titanate and Barium Titanate  

SciTech Connect

Hydrogen is a potential clean-burning, next-generation fuel for vehicle and stationary power. Unfortunately, hydrogen is also well known to have serious materials compatibility issues in metals, polymers, and ceramics. Piezoelectric actuator materials proposed for low-cost, high efficiency high-pressure hydrogen internal combustion engines (HICE) are known to degrade rapidly in hydrogen. This limits their potential use and poses challenges for HICE. Hydrogen-induced degradation of piezoelectrics is also an issue for low-pressure hydrogen passivation in ferroelectric random access memory. Currently, there is a lack of data in the literature on hydrogen species diffusion in piezoelectrics in the temperature range appropriate for the HICE as charged via a gaseous route. We present 1HNMR quantification of the local hydrogen species diffusion within lead zirconate titanate and barium titanate on samples charged by exposure to high-pressure gaseous hydrogen ?32?MPa. Results are discussed in context of theoretically predicted interstitial hydrogen lattice sites and aqueous charging experiments from existing literature.

Alvine, Kyle J.; Vijayakumar, M.; Bowden, Mark E.; Schemer-Kohrn, Alan L.; Pitman, Stan G.

2012-08-28

59

Hydrogen diffusion in lead zirconate titanate and barium titanate  

NASA Astrophysics Data System (ADS)

Hydrogen is a potential clean-burning, next-generation fuel for vehicle and stationary power. Unfortunately, hydrogen is also well known to have serious materials compatibility issues in metals, polymers, and ceramics. Piezoelectric actuator materials proposed for low-cost, high efficiency high-pressure hydrogen internal combustion engines (HICE) are known to degrade rapidly in hydrogen. This limits their potential use and poses challenges for HICE. Hydrogen-induced degradation of piezoelectrics is also an issue for low-pressure hydrogen passivation in ferroelectric random access memory. Currently, there is a lack of data in the literature on hydrogen species diffusion in piezoelectrics in the temperature range appropriate for the HICE as charged via a gaseous route. We present 1HNMR quantification of the local hydrogen species diffusion within lead zirconate titanate and barium titanate on samples charged by exposure to high-pressure gaseous hydrogen ~32 MPa. Results are discussed in context of theoretically predicted interstitial hydrogen lattice sites and aqueous charging experiments from existing literature.

Alvine, K. J.; Vijayakumar, M.; Bowden, M. E.; Schemer-Kohrn, A. L.; Pitman, S. G.

2012-08-01

60

Energy conversion with Zr-rich lead zirconate/titanate ceramics  

SciTech Connect

The conversion efficiency and power output to convert thermal energy to electrical energy by means of a ferroelectric{endash}ferroelectric phase transition has been investigated. The material used was the ceramic mixed system lead zirconate/titanate (PZT) with a very Zr-enriched composition (Zr/Ti=97/3{percent}). We have studied the performance dependence on sample thickness and working frequency, the main relevant parameters for a given PZT composition. The observed optimum values of efficiency and power output are analyzed in terms of the two main characteristic relaxation times of the process, the thermal time (sample thickness dependent) and the electric time (thickness independent). Possible ways of improving the overall performance are discussed. {copyright} {ital 1997 American Institute of Physics.}

Duan, N.; Cereceda, N.; Noheda, B.; Raul Fernandez-del-Castillo, J.; Gonzalo, J.A. [Departamento de Fisica de Materiales, Universidad Autonoma de Madrid, 28049 Madrid (Spain)

1997-09-01

61

Phase characterization of lead zirconate titanate obtained from organic solutions of citrates  

SciTech Connect

This paper reports that lead zirconate titanate (PZT) with several Zr/Ti ratios was prepared by the organic solution of citrates of the respective cations. The Rietveld method was applied to perform quantitative analysis of the coexisting phases. The ratio of tetragonal/rhombohedral phases increased with calcination temperature. For the composition where Zr/Ti = 53/47, the tetragonal quantity varied from 25% to 35% for temperatures ranging from 600[degrees] to 800[degrees]C. For the powder with Zr/Ti = 57/43, only the rhombohedral phase was observed after calcination at 700[degrees]C. For the powder with Zr/Ti = 49/51, only the tetragonal phase was observed after calcination at 800[degrees]C. The amount of tetragonal phase was controlled in Zr/Ti = 55/45 by seeding the powder with the tetragonal phase of PZT.

Zaghete, M.A.; Vanela, J.A. (Sao Paulo Univ., SP (Brazil). Inst. de Quimica); Santos, C.O.P. (Sao Paulo Univ., SP (Brazil)); Longo, E. (Sao Carlos Univ., SP (Brazil). Dept. de Quimica); Mascarenhas, Y.P. (Sao Paulo Univ., SP (Brazil). Inst. de Fisica)

1992-08-01

62

Pressure-temperature phase diagram for a tin modified lead zirconate titanate ceramic.  

SciTech Connect

Structural phase transformations between ferroelectric (FE), antiferroelectric (AFE), and paraelectric (FE) phases are frequently observed in the zirconia-rich phase region on the lead zirconate-titanate (PZT) phase diagram. Since the free energy difference among these phases is small, phase transformation can be easily induced by temperature, pressure and electric field. These induced transformation characteristics have been used for many practical applications. This study focuses on a hydrostatic pressure induced FE-to-AFE phase transformation in a tin modified PZT ceramic (PSZT). The relative phase stability between FE and AFE phases is determined by the dielectric permittivity measurement as a function of temperature from -60 C to 125 C. A pressure-temperature phase diagram for the PSZT system will be presented.

Grubbs, Robert K.; DiAntonio, Christopher Brian; Yang, Pin; Roesler, Alexander William; Montgomery, Stephen Tedford; Moore, Roger Howard

2010-06-01

63

Fatigue responses of lead zirconate titanate stacks under semibipolar electric cycling with mechanical preload  

NASA Astrophysics Data System (ADS)

Lead zirconate titanate (PZT) stacks that had an interdigital internal electrode configuration were tested to more than 108 cycles. A 100 Hz semibipolar sine wave with a field range of +4.5/-0.9 kV/mm was used in cycling with a concurrently-applied 20 MPa preload. Significant reductions in piezoelectric and dielectric responses were observed during the cycling depending on the measuring condition. Extensive partial discharges were also observed. These surface events resulted in the erosion of external electrode and the exposure of internal electrodes. Sections prepared by sequential polishing technique revealed a variety of damage mechanisms including delaminations, pores, and etch grooves. The scale of damage was correlated with the degree of fatigue-induced reduction in piezoelectric and dielectric responses. The results from this study demonstrate the feasibility of using a semibipolar mode to drive a PZT stack under a mechanical preload and illustrate the potential fatigue and damages of the stack in service.

Wang, Hong; Cooper, Thomas A.; Lin, Hua-Tay; Wereszczak, Andrew A.

2010-10-01

64

Lead zirconate titanate fiber/polymer composites prepared by a replication process  

SciTech Connect

The woven replication process was used to fabricate lead zirconate titanate (PZT)/polymer composites with 1-3, 2-3, and 3-3 connectivities by starting with novoloid-derived carbon fiber, woven fabric, and nonwoven felt templates, respectively. Activated carbon-fiber template material was impregnated with PZT by soaking it in a solution containing stoichiometric amounts of dissolved lead, zirconium, titanium, and niobium ions. Heat treatment burned out the carbon, leaving a PZT replica with the same form as the template material. Replicas were sintered in a controlled atmosphere and back-filled with an epoxy polymer to form final composites. This method, which is believed to be adaptable for mass production, is capable of producing composites and extremely fine microstructures. Woven composite samples have fiber tow diameters of 200 to 250 {mu}m and spacings between tows of about 150 to 250 {mu}m. Average d{sub 33} = 90 pC/N, g{sub 33} = 211 mV {center dot} m/N, and d{sub h}g{sub h} hydrophone figure of merit of 2100 {times} 10{sup {minus}15} m{sup 2}/N values are reported for woven PZT/polymer composites.

Waller, D.J.; Safari, A. (Dept. of Ceramic Engineering, Rutgers, State Univ. of New Jersey, Piscataway, NJ (US)); Card, R.J.; O'Toole, M.P. (Chemical Research Div., American Cyanamid Co., Stamford, CT (US))

1990-11-01

65

The development of lead zirconate titanate thin films for piezoelectric microactuators  

NASA Astrophysics Data System (ADS)

Piezoelectric actuation of a thin film is one means used for electrical-mechanical transduction in Microelectromechanical systems (MEMS). Currently, the most commonly employed piezoelectric thin-film material is ZnO. Replacing ZnO with certain compositions of lead zirconate titanate (PZT) should improve the performance of many MEMS devices due to the significantly greater piezoelectric coefficients of PZT (˜20 times greater than ZnO). In this dissertation I investigate the growth and properties---particularly piezoelectric properties---of PZT thin films. I also fabricate a PZT-based MEMS structure, a flexural plate wave (FPW) pump, and compare its performance with similar ZnO-based devices. PZT films of two compositions, Pb(Zr0.7Ti0.3)O 3 and Pb(Zr0.5Ti0.5)O3, were grown using reactive, multi-target, RF-magnetron sputtering on Pt-coated silicon wafers. Films were deposited at temperatures from 200°C to 400°C and rapid thermally annealed between 450°C and 700°C to crystallize perovskite PZT. The effects of as-deposited lead excess and deficiency on perovskite phase formation and film properties were studied. Films of composition Pb(Zr 0.5Ti0.5)O3, with relative dielectric constants of 1000, remanent polarizations of 20°C/cm2, coercive fields of 60 kV/cm, and effective piezoelectric d33 coefficients of 50 pm/V were obtained. These films show promise for use in MEMS. PZT films also were grown on a series of substrates using pulsed laser deposition (PLD). Epitaxial (100) films were obtained on LaAlO3 single crystal substrates, and randomly oriented films were obtained on Pt-coated silicon wafers. A conducting oxide electrode, (La0.5Sr0.5 )CoO3, was used for these films. Good structural and ferroelectric properties were obtained, however these films have limitations for use in MEMS. An FPW pump was fabricated using a sol-gel PZT thin film. Measured wave amplitudes were significantly higher than those of a similar ZnO-based device at the same driving voltage---250 A on a 5-finger pair PZT device as compared to 145 A on a 25-finger pair ZnO device. Estimations of pumping speed indicate that the PZT device should have a pumping speed more than an order of magnitude greater than the ZnO device.

Nickles, Annabel Susan

66

Characterization of PZT Films Fatigued at Low Frequency.  

National Technical Information Service (NTIS)

We report a method using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX) Analysis, Scanning Ion Microscopy (SIM), and polarization-voltage hysteresis data to investigate changes that occur in lead zirconate titanate (PZT) thin films fati...

R. A. Lipeles B. A. Morgan M. S. Leung

1992-01-01

67

Strain-Induced Electrical Properties of Lead Zirconate Titanate Thin Films on a Si wafer with Controlled Oxide Electrode Structure  

NASA Astrophysics Data System (ADS)

This paper shows the electrical properties of ferroelectric thin films with large compressive residual stress. In this study, the large compressive strain was applied to lead zirconate titanate (PZT) thin films by designing the bottom electrode structure on a Si wafer. The materials selected for the bottom electrode were lanthanum nickel oxide (LNO) and lanthanum strontium cobalt oxide [LSCO; (La0.5Sr0.5)CoO3] from the viewpoint of thermal expansion coefficients. As a result, the PZT thin films with morphotropic phase boundary (MPB) composition received compressive residual stress up to approximately 0.8 GPa from the bottom electrode even on a Si wafer. The compressive residual stress concomitantly increased with increasing LSCO layer thickness. In addition, the remanent polarization of the PZT thin films increased with increasing compressive residual stress.

Ohno, Tomoya; Ishiduka, Masaaki; Arai, Takashi; Yanagida, Hiroaki; Matsuda, Takeshi; Sakamoto, Naonori; Wakiya, Naoki; Suzuki, Hisao

2012-09-01

68

Strength Properties of Aged Poled Lead Zirconate Titanate Subjected to Electromechanical Loadings  

SciTech Connect

Electric field and aging time are two important factors that affect the mechanical strength and long-term reliability of lead zirconate titanate or PZT actuators. In the present work, a commercial PZT-5A aged four years was examined using ball-on-ring (BoR) mechanical testing under coupled electric fields. The electric field range of -3E{sub c} to +3E{sub c} (E{sub c}, coercive electric field) was studied (i.e., -3E{sub c}, -E{sub c}, 0, +E{sub c}, +2E{sub c}, and +3E{sub c}) with a controlled electric loading path. A Weibull distribution was used to interpret the mechanical strength data. With an electric field preloaded from 0 to -3E{sub c}, it was found that subsequent increases in the electric field resulted in an asymmetrical V-shaped curve of mechanical strength against the electric field. The bottom of the V curve was located near the zero electric field level. Microscopy analysis showed that pores were the strength limiter for the tested PZT under electromechanical loadings.

Zhang, Kewei [ORNL; Zeng, Fan W [ORNL; Wang, Hong [ORNL; Lin, Hua-Tay [ORNL

2012-01-01

69

Electronic properties of A -site substituted lead zirconate titanate: Density functional calculations  

NASA Astrophysics Data System (ADS)

First-principles density functional theory calculations have been applied to study the electronic and optical properties of A -site substituted lead zirconate titanate (PZT), where group IIIA and group VB elements partially substitute Pb sites. The conduction band minima in the group IIIA element substituted PZT systems are found to be shared by Ti3d and dopant states, which reduce the occupation on Ti3d states by the electrons. Moreover, correlations between dopant electrons introduce the Mott-Hubbard band gap into PZT, which is intrinsically a charge-transfer insulator. This leads to a systematic reduction of energy and optical band gaps with increased atomic number of group IIIA substitutes. Similar chemical trend was found for group VB substitutes, which is, however, closely related to the electron bandwidth of Ti3d states in the charge-transfer band gaps. All the trivalent substitutes are confirmed to effectively dilute the concentration of the oxygen vacancies under Pb-deficient conditions by our theoretical calculations.

Zhang, Zhen; Wu, Ping; Ong, Khuong P.; Lu, Li; Shu, Chang

2007-09-01

70

Strength properties of aged poled lead zirconate titanate subjected to electromechanical loadings  

NASA Astrophysics Data System (ADS)

Electric field and aging time are two important factors that affect the mechanical strength and long-term reliability of lead zirconate titanate or PZT actuators. In the present work, a commercial PZT-5A aged four years was examined using ball-on-ring (BoR) mechanical testing under coupled electric fields. The electric field range of -3Ec to +3Ec (Ec, coercive electric field) was studied (i.e., -3Ec, -Ec, 0, +Ec, +2Ec, and +3Ec) with a controlled electric loading path. A Weibull distribution was used to interpret the mechanical strength data. With an electric field preloaded from 0 to -3Ec, it was found that subsequent increases in the electric field resulted in an asymmetrical V-shaped curve of mechanical strength against the electric field. The bottom of the V curve was located near the zero electric field level. Microscopy analysis showed that pores were the strength limiter for the tested PZT under electromechanical loadings.

Zhang, Kewei; Zeng, Fan Wen; Wang, Hong; Lin, Hua-Tay

2012-11-01

71

A statistical model approximation for perovskite solid-solutions: A Raman study of lead-zirconate-titanate single crystal  

NASA Astrophysics Data System (ADS)

Lead titanate (PbTiO3) is a classical example of a ferroelectric perovskite oxide illustrating a displacive phase transition accompanied by softening of a symmetry-breaking mode. The underlying assumption justifying the soft-mode theory is that the crystal is macroscopically sufficiently uniform that a meaningful free energy function can be formed. In contrast to PbTiO3, experimental studies show that the phase transition behaviour of lead-zirconate-titanate solid solution (PZT) is far more subtle. Most of the studies on the PZT system have been dedicated to ceramic or powder samples, in which case an unambiguous soft-mode study is not possible, as modes with different symmetries appear together. Our Raman scattering study on titanium-rich PZT single crystal shows that the phase transitions in PZT cannot be described by a simple soft-mode theory. In strong contrast to PbTiO3, splitting of transverse E-symmetry modes reveals that there are different locally ordered regions. The role of crystal defects, random distribution of Ti and Zr at the B-cation site and Pb ions shifted away from their ideal positions, dictates the phase transition mechanism. A statistical model explaining the observed peak splitting and phase transformation to a complex state with spatially varying local order in the vicinity of the morphotropic phase boundary is given.

Frantti, J.; Fujioka, Y.; Puretzky, A.; Xie, Y.; Ye, Z.-G.; Glazer, A. M.

2013-05-01

72

A statistical model approximation for perovskite solid-solutions: a Raman study of lead-zirconate- titanate single crystal  

SciTech Connect

Lead titanate (PbTiO3) is a classical example of a ferroelectric perovskite oxide illustrating a displacive phase transition accompanied by a softening of a symmetry-breaking mode. The underlying assumption justifying the soft-mode theory is that the crystal is macroscopically sufficiently uniform so that a meaningful free energy function can be formed. In contrast to PbTiO3, experimental studies show that the phase transition behaviour of lead-zirconate-titanate solid solution (PZT) is far more subtle. Most of the studies on the PZT system have been dedicated to ceramic or powder samples, in which case an unambiguous soft-mode study is not possible, as modes with different symmetries appear together. Our Raman scattering study on titanium-rich PZT single crystal shows that the phase transitions in PZT cannot be described by a simple soft-mode theory. In strong contrast to PbTiO3, splitting of transverse E-symmetry modes reveals that there are different locally-ordered regions. The role of crystal defects, random distribution of Ti and Zr at the B- cation site and Pb ions shifted away from their ideal positions, dictates the phase transition mechanism. A statistical model explaining the observed peak splitting and phase transformation to a complex state with spatially varying local order in the vicinity of the morphotropic phase boundary is given.

Frantti, Johannes [Aalto University, Finland; Fujioka, Y [Aalto University, Finland; Puretzky, Alexander A [ORNL; Xie, Y [Simon Fraser University, Canada; Glazer, A [Clarendon Laboratory, Department of Physics, University of Oxford

2013-01-01

73

Substrate Clamping Effects on Irreversible Domain Wall Dynamics in Lead Zirconate Titanate Thin Films  

SciTech Connect

The role of long-range strain interactions on domain wall dynamics is explored through macroscopic and local measurements of nonlinear behavior in mechanically clamped and released polycrystalline lead zirconate-titanate (PZT) films. Released films show a dramatic change in the global dielectric nonlinearity and its frequency dependence as a function of mechanical clamping. Furthermore, we observe a transition from strong clustering of the nonlinear response for the clamped case to almost uniform nonlinearity for the released film. This behavior is ascribed to increased mobility of domain walls. These results suggest the dominant role of collective strain interactions mediated by the local and global mechanical boundary conditions on the domain wall dynamics. The work presented in this Letter demonstrates that measurements on clamped films may considerably underestimate the piezoelectric coefficients and coupling constants of released structures used in microelectromechanical systems, energy harvesting systems, and microrobots.

Griggio, Flavio [ORNL; Jesse, Stephen [ORNL; Kumar, Amit [ORNL; Ovchinnikov, Oleg S [ORNL; Kim, H. [Pennsylvania State University, University Park, PA; Jackson, T. N. [Pennsylvania State University, University Park, PA; Damjanovic, Dragan [ORNL; Kalinin, Sergei V [ORNL; Trolier-Mckinstry, Susan E [ORNL

2012-01-01

74

Piezoelectric and Dielectric Performance of Poled Lead Zirconate Titanate Subjected to Electric Cyclic Fatigue  

SciTech Connect

Poled lead zirconate titanate (PZT) material as a single-layer plate was tested using piezodilatometer under electric cyclic loading in both unipolar and bipolar modes. Their responses were evaluated using unipolar and bipolar measurements on the same setup. Mechanical strain and charge density or polarization loops exhibited various variations when the material was cycled to more than 10^8 cycles. Important quantities including loop amplitude, hysteresis, switchable polarization, coercive field have been characterized accordingly under corresponding measurement conditions. At the same time, offset polarization and bias electric field of the material were observed to be changed and the trend was found to be related to the measurement condition also. Finally, the piezoelectric and dielectric coefficients were analyzed and their implications to the application of interest have been discussed.

Wang, Hong [ORNL; Matsunaga, Tadashi [ORNL; Lin, Hua-Tay [ORNL; Mottern, Alexander M [ORNL; Wereszczak, Andrew A [ORNL

2012-01-01

75

Electrical fatigue behaviour in lead zirconate titanate: an experimental and theoretical study  

NASA Astrophysics Data System (ADS)

A systematic investigation on electrical fatigue in lead zirconate titanate (PZT) is carried out for different loading frequencies. Experiments are conducted up to 106 cycles to measure the electrical displacement and longitudinal strain on bulk ceramics in the bipolar mode with large electrical loading conditions. A simplified macroscopic model based on physical mechanisms of domain switching is developed to predict the non-linear behaviour. In this model, the volume fraction of a domain is used as the internal variable by considering the mechanisms of domain nucleation and propagation (domain wall movement). The measured material properties at different fatigue cycles are incorporated into the switching model as damage parameters and the classical strain versus electric field and electric displacement versus electric field curves are simulated. Comparison between the experiments and simulations shows that the proposed model can reproduce the characteristics of non-linear as well as fatigue responses.

Bhattacharyya, Mainak; Arockiarajan, A.

2013-08-01

76

THz Emission from PZT Nanotubes  

Microsoft Academic Search

We report THz emission from lead zirconate-titanate (PZT) nanotube arrays, which is totally absent in flat films or bulk PZT; hence the effect is due to the nano-scale geometry of the tubes, which are 1 ? m in total diameter, 40 nm in wall thickness and standing normal to the Si substrates. The THz radiation is emitted within 0.2 ps

J. Banys; M. Ivanov; J. Macutkevic; A. Krotkus; H. J. Fan; S. Kawasaki; J. F. Scott

2009-01-01

77

Fatigue and failure responses of lead zirconate titanate multilayer actuator under unipolar high-field electric cycling  

SciTech Connect

Lead zirconate titanate (PZT) multilayer actuators with an interdigital electrode design were studied under high electric fields (3 and 6 kV/mm) in a unipolar cycling mode. A 100 Hz sine wave was used in cycling. Five specimens tested under 6 kV/mm failed from 3.8 10^5 to 7 10^5 cycles, whereas three other specimens tested under 3 kV/mm were found to be still functional after 10^8 cycles. Variations in piezoelectric and dielectric responses of the tested specimens were observed during the fatigue test, depending on the measuring and cycling conditions. Selected fatigued and damaged actuators were characterized using an impedance analyzer or small signal measurement. A scanning acoustic microscope also was employed as a nondestructive tool to detect the presence of defects. Failed plates were subsequently sectioned, and the extensive cracks and porous regions were observed to be across the PZT layers. The results from this study have demonstrated that the high-field cycling can accelerate the fatigue of PZT stacks as long as the partial discharge is controlled. The small signal measurement can also be integrated into the large signal measurement to characterize the fatigue response of PZT stacks in a more comprehensive basis. The former can further serve as an experimental method to monitor the behavior of PZT stacks.

Zeng, Fan W [ORNL; Wang, Hong [ORNL; Lin, Hua-Tay [ORNL

2013-01-01

78

Study of the characteristics of a piezoelectric lead zirconate titanate radiation detector using a pulsed xenon source  

SciTech Connect

The detector characteristics of piezoelectric lead zirconate titanate (PZT) were studied by directly irradiating a multilayered PZT detector with 400 MeV/n xenon ions. An extracted beam was processed with a rotating slit. Thus, passed through {approx}10{sup 3} xenon ions were available for 50 to 250 {mu}s. The effect of polarization on the output signal was discussed, and the optimal electrode configuration was determined. The output signal appeared as an isolated pulse whose amplitude was qualitatively understood by the Bethe-Bloch formula. However, the calculated and the observed values differed depending on the rotation speed of the slit. A process that can explain the differences is presented here. The output signal appearing beyond the range of 400 MeV/n xenon ion beam was discussed. The sensitivity was compared with that obtained with hypervelocity collision of dust.

Miyachi, Takashi [Research Institute of Science and Engineering, Waseda University, Tokyo 169-8555 (Japan); Planetary Exploration Research Center, Chiba Institute of Technology, Narashino, Chiba 275-0016 (Japan); Fujii, Masayuki; Hasebe, Nobuyuki; Okudaira, Osamu [Research Institute of Science and Engineering, Waseda University, Tokyo 169-8555 (Japan); Takechi, Seiji; Kurozumi, Atsuma; Morinaga, Shinya; Uno, Takefumi [Graduate School of Engineering, Osaka-City University, Osaka 558-8585 (Japan); Shibata, Hiromi [Graduate School of Engineering, Kyoto-University, Kyoto-606-8501 (Japan); Kobayashi, Masanori [Planetary Exploration Research Center, Chiba Institute of Technology, Narashino, Chiba 275-0016 (Japan); Murakami, Takeshi; Uchihori, Yukio [National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Okada, Nagaya [Honda Electronics Co. Ltd., Toyohashi, Aichi 441-3193 (Japan)

2010-05-15

79

Phase Shift of a Coplanar Waveguide by Bias Voltage on Thick Lead Zirconate Titanate Film at Microwave Frequency  

NASA Astrophysics Data System (ADS)

A coplanar waveguide was fabricated by depositing a 1-?m-thick Au film on a multilayer dielectric, consisting of a 2-?m-thick lead zirconate titanate (PZT) film over an Al2O3 substrate, through etching. Following this, the reflection constant, transmission constant, and phase variation were measured for this transmission line as bias voltage was varied from 30 to 50 V. As a result, it was confirmed that the phase variation becomes about 15° at a 50 V bias at a frequency of 10 GHz. We then confirmed the basic input-output characteristics of this type of structure in the microwave band. Finally, the relative permittivity of a PZT thick film as a coplanar waveguide was estimated using the measurement results of relative permittivity according to the split cavity resonator method, and phase variation under the condition in which a bias voltage was applied.

Shibata, Kouji; Iijima, Takashi; Masuda, Yoichiro

2008-09-01

80

Electrode size dependence of piezoelectric response of lead zirconate titanate thin films measured by double beam laser interferometry  

NASA Astrophysics Data System (ADS)

The electrode size dependence of the effective large signal piezoelectric response coefficient (d33,f) of lead zirconate titanate (PZT) thin films is investigated by using double beam laser interferometer measurements and finite element modeling. The experimentally observed electrode size dependence is shown to arise from a contribution from the substrate. The intrinsic PZT contribution to d33,f is independent of electrode size and is equal to the theoretical value derived assuming a rigid substrate. The substrate contribution is strongly dependent on the relative size of the electrode with respect to the substrate thickness. For electrode sizes larger than the substrate thickness, the substrate contribution is positive and for electrode sizes smaller than the substrate thickness, the substrate contribution is negative. In the case of silicon substrates, if the electrode size is equal to the substrate thickness, the substrate contribution vanishes, and the measured value of d33,f is equal to the theoretical value under the rigid substrate assumption.

Sivaramakrishnan, S.; Mardilovich, P.; Mason, A.; Roelofs, A.; Schmitz-Kempen, T.; Tiedke, S.

2013-09-01

81

Effects of Hydrolysis on Metallo-Organic Solution Deposition of PZT Films.  

National Technical Information Service (NTIS)

The effects of hydrolysis on the degree of polymerization during metallo-organic solution deposition of lead zirconate titanate (PZT) films have been investigated. The reaction of lead 2-ethylhexanoate, zirconium n-tetrapropoxide, and titanium tetrabutoxi...

R. A. Lipeles D. J. Coleman M. S. Leung

1986-01-01

82

Study of Zinc and Niobium Modified Lead Zirconate Titanate Fiber/Epoxy 1-3 Composites  

NASA Astrophysics Data System (ADS)

Zinc and niobium modified lead zirconate titanate (PZN-PZT) fibers were prepared by the sol-gel method. After sintering at various temperatures the crystal structure of the ceramic fibers was determined by X-ray diffraction. The morphology of the ceramic fibers was studied using a scanning electron microscope. A bundle of ceramic fibers of 25 ?m diameter was placed in a plastic tube, which was then filled with epoxy. After curing, a PZN-PZT fiber/epoxy 1-3 composite rod was formed. The rod was sliced into disks which were then polished to a thickness of approximately 40 ?m. A composite disk with 0.62 ceramic volume fraction was poled under an electric field of 3.5 kV/mm at 120°C for 15 min. The electromechanical coupling coefficient kt, piezoelectric coefficient d33 and relative permittivity \\varepsilon of the disk were found to be 0.67, 403 pC/N and 1300, respectively. The hysteresis loop of the composite was also determined, and the remnant polarization Pr was found to be 12 ?C/cm2.

Li, Kun; Chan, Helen Lai-Wa; Choy, Chung-Loong

2002-11-01

83

In situ cell detection using piezoelectric lead zirconate titanate-stainless steel cantilevers  

NASA Astrophysics Data System (ADS)

We have investigated piezoelectric lead zirconate titanate (PZT)-stainless steel cantilevers as real-time in-water cell detectors using yeast cells as a model system. Earlier studies have shown that mass changes of a cantilever can be detected by monitoring the resonance frequency shift. In this study, two PZT-stainless steel cantilevers with different sensitivities were used to detect the presence of yeast cells in a suspension. The stainless steel cantilever tip was coated with poly-L-lysine that attracted yeast cells from the suspension, and immobilized them on the cantilever surface. After immersing the poly-L-lysine coated tip in a yeast suspension, the flexural resonance frequency of the cantilever was monitored with time. The flexural resonance frequency decreased with time in agreement with the optical micrographs that showed increasing amount of adsorbed yeast cells with time. The resonance frequency shifts are further shown to be consistent with both the mass of immobilized cells on the poly-L-lysine coated stainless steel surface and that deduced from the optical micrographs. Furthermore, under the present experimental conditions where the cell diffusion distance is smaller than the linear dimension of the adsorption area, it is shown that the rate of resonance frequency shift is linear with the cell concentration and the rate of resonance frequency shift can be used to quantify the cell concentration.

Yi, Jeong W.; Shih, Wan Y.; Mutharasan, R.; Shih, Wei-Heng

2003-01-01

84

Alternating-current-assisted poling of lead zirconate titanate PZT  

SciTech Connect

A modification of the conventional poling procedure for piezoelectric materials was investigated because of inconsistencies in the literature. Preliminary investigations appeared to support the theory of ac-assisted poling. However, a temperature study/limited duty cycle experiment seemed to indicate that the increase in piezoelectric response was probably due to heat produced by the body in resonance.

Gallo, C.A.; Schulze, W.A.

1987-02-01

85

Influence of the Niobium or Fluorine Dopant Concentration on the Properties of Mn-Doped Lead Zirconate Titanate Ceramics  

NASA Astrophysics Data System (ADS)

In this paper, we report on the effect of donor addition (Nb5+ or F-) on the electrical and piezoelectric properties and crystallographic characteristics of Mn-doped lead zirconate titanate (PZT) ceramics. Samples were prepared chemically by coprecipitation of oxalates and hydroxides. The niobium ion was incorporated in the B site whereas the fluorine ion was introduced in the anionic site. Structural analysis (XRD) and measurement of electrical properties were carried out. Electron spin resonance was used to determined the valency states of manganese in PZT ceramics. From the experimental results, the F-O substitution decreases the amount of oxygen vacancies in the Mn-doped PZT, and the valency states remain unchanged. However, a small number of oxygen vacancies may exist in PZT doped with 1 at.% manganese and 2 at.% fluorine. In the (Mn,Nb) co-doping case, the valency states vary from 4+ to 2+ and the number of oxygen vacancies is lower or even almost equal to zero. Thus the electroneutrality is achieved by lead vacancies.

Boucher, Eric; Guiffard, Benoit; Lebrun, Laurent; Guyomar, Daniel

2004-08-01

86

Crystallization of lead zirconate titanate films by laser annealing  

NASA Astrophysics Data System (ADS)

The structure of lead zirconate titanate Pb(Zr x Ti1 - x )O3 thin films grown by chemical solution deposition on Si-SiO2-Ti-Pt substrates has been studied using transmission electron microscopy and energy-dispersive analysis. Films crystallization has been performed using laser annealing. It has been found that, in contrast to isothermal annealing where nucleation on the platinum layer dominates, crystallization and growth of spherical perovskite crystals occur in the film bulk. The perovskite phase crystal size increases from 10 to 120 nm with increasing laser beam energy.

Khmelenin, D. N.; Zhigalina, O. M.; Vorotilov, K. A.; Lebo, I. G.

2012-05-01

87

Preparation of PZT powders and ceramics via a hybrid method of sol–gel and ultrasonic atomization  

Microsoft Academic Search

Lead zirconate titanate (PZT) (52\\/48) powders were synthesized by a hybrid method of sol–gel and ultrasonic atomization. X-ray diffraction (XRD) results showed that perovskite phase of PZT is formed at 400°C. This temperature is much lower than the calcination temperatures (500–900°C) required by other processes. Phase-pure PZT powders were obtained at 700°C. The PZT ceramics sintered at 1150°C for 4h

Z. J. Xu; R. Q. Chu; G. R. Li; Xin Shao; Q. R. Yin

2005-01-01

88

Piezoelectric properties of sputtered PZT films: influence of structure, micro structure, film thickness (Zr,Ti) ratio and Nb substitution  

Microsoft Academic Search

Lead titanate zirconate Pb(Zr,Ti)O3 (PZT) with different (Zr,Ti) ratio and Niobium (Nb) doped PZT thin films were deposited on silicon substrates by R.F. magnetron sputtering. The Zr\\/Ti ratio varied between the quadratic to the rhombohedric phases. For the thickness influence study, we have chosen PZT films with the 5446 composition. The Nb concentration incorporated in PZT films varied between 1at%

D. Remiens; E. Cattan; C. Soyer; T. Haccart

2002-01-01

89

Effect of Hydrogen Anneals on Niobium-Doped Lead Zirconate Titanate Capacitors with Lanthanum Strontium Cobalt Oxide/Platinum Electrodes  

NASA Astrophysics Data System (ADS)

Ferroelectric capacitors, being oxide ceramics, are very sensitive to the effects of hydrogen environments at elevated temperatures [H. Ashida et al..: Integr. Ferroelectr. 21 (1998) 97]. After a capacitor has been exposed directly to a annealing hydrogen environment at low hydrogen partial pressures, the electrical properties of the device can deteriorate and leakage currents can increase. At higher hydrogen concentration gradients, such as the formidable forming gas annealing, physical failure of the inter-layer dielectric (ILD) and/or top electrode adhesion can occur. The authors have examined various structural approaches to mitigate the effects of hydrogen damage on integrated ferroelectric lead zirconate titanate (PZT) capacitors. These approaches, including the use of a titanium dioxide barrier layer above the PZT to impede the reducing effect of hydrogen on the ceramic and the use of electrode layers other than platinum to eliminate the generation of free hydrogen ions by catalyst action [S. Aggarwal et al..: Appl. Phys. Lett. 73 (1998) 1973]. The authors have found that niobium-doped PZT capacitors using LSCO/platinum electrodes passivated with titanium dioxide will recover from 1% forming gas annealing within 30 minutes at 450°C in nitrogen.

Evans, Joe; Jr., Jr.; Boyer, Leonard; Velasquez, Geri; Ramesh, Ramamoorthy; Aggarwal, Sanjeev; Keramidas, Vassillis

1999-09-01

90

Ferroelectric/ferroelastic behavior and piezoelectric response of lead zirconate titanate thin films under nanoindentation  

NASA Astrophysics Data System (ADS)

The electromechanical response of pure lead zirconate titanate (PZT) and Mn-doped PZT thin ferroelectric films under nanoindentation forces of up to 500 mN was investigated. The stress-induced current transients were measured as a function of the externally applied load on films of different thicknesses using a spherical WC-Co cermet indenter of 500 ?m nominal radius. It was found that the quasi-static current generated through the direct piezoelectric effect is superimposed with a contribution from irreversible domain processes during the loading/unloading cycle. The film thickness dependency of the electrical transients and an asymmetry of the current-force curves are attributed to the in-plane clamping stress in the films produced by a dissimilar substrate. Analysis of corresponding charge-force hysteresis loops revealed a significant role for the residual stress state on the polarization switching in thin films. By the application of an indentation force, a portion of Barkhausen jumps was empirically estimated to increase as a consequence of reduction of the clamping effect on domains. The Rayleigh hysteretic charge-force curves showed recovery of the charge released during the load-unload stress cycle. For the thicker 700 nm films, the total charge released during loading was fully recovered with weak hysteresis. In contrast, strong in-plane clamping stresses in the 70 nm thick films are suggested to be reponsible for incomplete recovery upon unloading. A considerable domain-wall contribution to the electromechanical response was demonstrated by an enhanced polarization state, which was shown by an increase of the effective piezoelectric coefficient deff of about 35% of its initial value for the thin films at a maximum force of 500 mN.

Koval, V.; Reece, M. J.; Bushby, A. J.

2005-04-01

91

Effect of manganese doping on the size effect of lead zirconate titanate thin films and the extrinsic nature of 'dead layers'  

NASA Astrophysics Data System (ADS)

We have investigated the size effect in lead zirconate titanate (PZT) thin films with a range of manganese (Mn) doping concentrations. We found that the dynamic size effect in the conventional Pt/PZT/Pt thin-film capacitors could be systematically reduced and almost completely eliminated by increasing Mn doping concentration. The interfacial layer at the electrode-film interface appears to disappear almost entirely for the PZT films with ~2% Mn doping levels, confirmed by the fits using the conventional 'in-series capacitor' model. Our work indicates that the dynamic size effect in ferroelectrics is extrinsic in nature, supporting the work by Saad et al. Other implications of our results have also been discussed. By comparing a variety of experimental studies in the literature we propose a scenario that the 'dead layer' between PZT (or barium strontium titanate, BST) and metal electrodes such as Pt and Au might have a defective pyrochlore/fluorite-like structure (possibly with a small portion of ferroelectric perovskite phase). This scenario is then generalized by including the effect of the grain-boundary dead layer on the collapse of the dielectric constant in thinner films.

Lou, X. J.; Wang, J.

2010-02-01

92

Temperature dependence of a PZT piezoelectric sensor for Mercury Dust Monitor up to 150 °C  

Microsoft Academic Search

We have been developing a cosmic dust detector for BepiColombo Mercury exploration mission, called Mercury Dust Monitor (MDM). The MDM uses piezoelectric sensors made of lead zirconate titanate (PZT) ceramics for estimation of dust flux and momentum of incident particles. The PZT sensors of MDM, installed on the surface of a side panel of the MMO without a sunshade, will

Takeo Iwai

2008-01-01

93

Current—voltage characteristics of lead zirconate titanate/nickel bilayered hollow cylindrical magnetoelectric composites  

NASA Astrophysics Data System (ADS)

Current-voltage measurements obtained from lead zirconate titanate/nickel bilayered hollow cylindrical magnetoelectric composite showed that a sinusoidal current applied to the copper coil wrapped around the hollow cylinder circumference induces voltage across the lead zirconate titanate layer thickness. The current-voltage coefficient and the maximum induced voltage in lead zirconate titanate at 1 kHz and resonance (60.1 kHz) frequencies increased linearly with the number of the coil turns and the applied current. The resonance frequency corresponds to the electromechanical resonance frequency. The current-voltage coefficient can be significantly improved by optimizing the magnetoelectric structure geometry and/or increasing the number of coil turns. Hollow cylindrical lead zirconate titanate/nickel structures can be potentially used as current sensors.

Pan, De-An; Zhang, Shen-Gen; Tian, Jian-Jun; Sun, Jun-Sai; Alex, Volinsky A.; Qiao, Li-Jie

2010-02-01

94

Orientation of rapid thermally annealed lead zirconate titanate thin films on (111) Pt substrate.  

National Technical Information Service (NTIS)

The nucleation, growth and orientation of lead zirconate titanate thin films prepared from organometallic precursor solutions by spin coating on (111) oriented platinum substrates and crystallized by rapid thermal annealing was investigated. The effects o...

K. G. Brooks I. M. Reaney R. Klissurska Y. Huang L. A. Bursill

1994-01-01

95

Study of Temperature Stability of Properties of Lead Zirconate Titanate Piezoceramic.  

National Technical Information Service (NTIS)

A study of the effects of temperature on properties of several compounds of the lead zirconate titanate system was made. Compounds that have higher temperature stability were determined. A study was made of changes in their properties under the simultaneo...

G. N. Vitalinskaya V. A. Doroshenko M. A. Ugryumova

1976-01-01

96

Molten salt synthesis of lead lanthanum zirconate titanate ceramic powders  

Microsoft Academic Search

Lead lanthanum zirconate titanate (Pb0.95La0.03)(Zr0.52Ti0.48)O3 (PLZT) was synthesized by one step molten salt method with the starting materials of PbC2O4, La2O3, ZrO(NO3)2·2H2O and TiO2 in the NaCl–KCl eutectic mixtures in the temperature range of 700–1000°C. The single phase of (Pb0.95La0.03)(Zr0.52Ti0.48)O3 powders was prepared at a temperature as low as 850°C for 5h. The effects of process parameters, such as soaking

Zongying Cai; Xianran Xing; Lu Li; Yeming Xu

2008-01-01

97

In situ neutron diffraction studies of a commercial, soft lead zirconate titanate ceramic: response to electric fields and mechanical stress  

NASA Astrophysics Data System (ADS)

Structural changes in commercial lead zirconate titanate (PZT) ceramics (EC-65) under the application of electric fields and mechanical stress were measured using neutron diffraction instruments at the Australian Nuclear Science and Technology Organisation (ANSTO) and the Oak Ridge National Laboratory (ORNL). The structural changes during electric-field application were measured on the WOMBAT beamline at ANSTO and include non-180° domain switching, lattice strains and field-induced phase transformations. Using time-resolved data acquisition capabilities, lattice strains were measured under cyclic electric fields at times as short as 30 ?s. Structural changes including the (002) and (200) lattice strains and non-180° domain switching were measured during uniaxial mechanical compression on the NRSF2 instrument at ORNL. Contraction of the crystallographic polarization axis, (002), and reorientation of non-180° domains occur at lowest stresses, followed by (200) elastic strains at higher stresses.

Pramanick, Abhijit; Prewitt, Anderson D.; Cottrell, Michelle A.; Lee, Wayne; Studer, Andrew J.; An, Ke; Hubbard, Camden R.; Jones, Jacob L.

2010-06-01

98

Vibration Characteristics of Piezoelectric Lead Zirconate Titanate by Fluid Flow in Intravascular Oxygenator  

NASA Astrophysics Data System (ADS)

In this paper, we describe the enhancement in oxygen transfer rate in hollow-fiber-membrane (HFM) modules using a plumbum piezoelectric lead zirconate titanate (PZT) actuator and a piezoelectric poly vinylidene fluoride (PVDF) sensor. We developed a vibrating intravascular lung assist device (VIVLAD) for patients having chronic respiratory problems and performed experiments on hydrodynamic flow through a bundle of sinusoidal vibrating hollow fibers. These modules were used to provide some insight into how wall vibrations might enhance the performance of an intravascular lung assist device. The experimental design and procedure are then applied to the fabrication of a device used to assess the effectiveness of membrane vibrations. The test section was a cylindrical duct with an inner diameter of 30 mm. The flow rate was controlled by a pump and monitored by a built-in flowmeter. The vibration apparatus was composed of a piezovibrator, a function generator, and a power amplifier. The direction of vibration was radial to the fluid flow. Gas flow rates of up to 6 L/min through 120-cm-long hollow fibers were achieved by exciting the piezovibrator. The time and frequency responses of PVDF sensors were investigated through various frequencies in VIVLAD. In these devices, the flow of blood and the source of oxygen were separated by a semipermeable membrane that allows oxygen and carbon dioxide to diffuse into and out of the fluid, respectively. Results of the experiments have shown that a vibrating intravascular lung assist device performs effectively.

Kim, Gi?Beum; Hong, Chul?Un; Kwon, Tae?Kyu

2006-04-01

99

Nonlinearity and scaling behavior in a soft lead zirconate titanate piezoceramic  

NASA Astrophysics Data System (ADS)

Lead oxide-based ferroelectrics, represented by lead zirconate titanate [Pb(Zr,Ti)O3] or PZT), are the most widely used materials for piezoelectric actuators, sensors, and transducers due to their excellent piezoelectric properties. Most of these piezoelectric materials are employed under a variety of strains (stress, electrical field, and temperature). It would thus be interesting to predict their behaviors under different excitations without having to perform too much experimental work, i.e., just carry out a single experiment and still be able to provide the other experimental values. The purpose of this paper has thus been to propose several behavioral laws linking the electrical field, temperature and mechanical stress. The first law rendered it possible to express the mechanical stress by an equivalent electric field [?E???T×P(E,T0)]. Subsequently, a law linking the electrical field and temperature {?E?[2?×P(E,?0)]×??} was proposed. From these two laws, a third law was identified reflecting the mechanical stress as an equivalent temperature; each expressed by a temperature equivalent stress (T??×??). After experimental validation of these laws, the mapping could be extended in order to predict the polarization behavior in the tensile stress zone as well as that as a function of the negative temperature.

Hajjaji, Abdelowahed; Guyomar, Daniel; Touhtouh, Samira; Pruvost, Sebastien; Boughaleb, Yahia; Rguiti, Mohamed; Courtois, Christian; Leriche, Anne; Benkhouja, Khalil

2010-09-01

100

Neutron irradiation effects on domain wall mobility and reversibility in lead zirconate titanate thin films  

NASA Astrophysics Data System (ADS)

The effects of neutron-induced damage on the ferroelectric properties of thin film lead zirconate titanate (PZT) were investigated. Two sets of PbZr0.52Ti0.48O3 films of varying initial quality were irradiated in a research nuclear reactor up to a maximum 1 MeV equivalent neutron fluence of (5.16 +/- 0.03) × 1015 cm-2. Changes in domain wall mobility and reversibility were characterized by polarization-electric field measurements, Rayleigh analysis, and analysis of first order reversal curves (FORC). With increasing fluence, extrinsic contributions to the small-signal permittivity diminished. Additionally, redistribution of irreversible hysterons towards higher coercive fields was observed accompanied by the formation of a secondary hysteron peak following exposure to high fluence levels. The changes are attributed to the radiation-induced formation of defect dipoles and other charged defects, which serve as effective domain wall pinning sites. Differences in damage accumulation rates with initial film quality were observed between the film sets suggesting a dominance of pre-irradiation microstructure on changes in macroscopic switching behavior.

Graham, Joseph T.; Brennecka, Geoff L.; Ferreira, Paulo; Small, Leo; Duquette, David; Apblett, Christopher; Landsberger, Sheldon; Ihlefeld, Jon F.

2013-03-01

101

Determination of the Linear Electrooptic Coefficient of a Lead Zirconate Titanate Thin Film Using Two-Beam Polarization Interferometer with an Adaptive Photodetector  

NASA Astrophysics Data System (ADS)

A novel interferometric modulation technique for optical thin-film testing using a two-beam polarization (TBP) interferometer with GaAs:Cr adaptive photodetector is presented. The technique enables determination of Pockels coefficient of thin films with a strong Fabry-Perot effect and automatic adjustment and maintenance operation point of the interferometer. We use this method for measuring the effective differential linear electrooptic coefficient re = r33-(n0/ne)3r13 of lead zirconate titanate (PZT) thin film. A strong hysteresis effect with a slightly asymmetric form of the hysteresis loop was observed for the dependence of the effective differential Pockels coefficient of the PZT thin film on the DC electric field. The values of re are in agreement with known data.

Spirin, Vasilii; Lee, Changho; No, Kwangsoo; Sokolov, Igor

1998-05-01

102

Improved dielectric properties of lead zirconate titanate thin films deposited on metal foils with LaNiO3 buffer layers  

NASA Astrophysics Data System (ADS)

Improved dielectric properties of lead zirconate titanate (PZT) films deposited on a variety of foils using buffer layers are reported. Foils include titanium, stainless steel, and nickel with LaNiO3(LNO) buffer layers which were prepared by sol-gel processing. High dielectric constant (330 for stainless steel, 420 for titanium, and 450 for nickel foils), low dielectric loss (<2.2% for titanium and 8% for stainless steel), symmetric ferroelectric C-V characteristics and P-E curves were obtained. The LNO layers are shown to provide an effective diffusion barrier for Ni and Cr and to restrict oxide layer formation (i.e., TiOx or NiOx) between the PZT film and the metallic foils during annealing in air.

Zou, Q.; Ruda, H. E.; Yacobi, B. G.

2001-02-01

103

Bias Field Effects on Microwave Frequency Behavior of PZT\\/YIG Magnetoelectric Bilayer  

Microsoft Academic Search

Magnetoelectric behavior of a yttrium iron garnet (YIG)\\/zirconate titanate (PZT) magnetoelectric bilayer composite was studied over 1-7 GHz under different bias magnetic fields and electric fields by using a broadband air-gap microstrip with the PZT\\/YIG loaded in the air gap. Electrostatically induced ferrimagnetic resonance (FMR) frequency shifts of the YIG\\/PZT bilayer composite were studied. The FMR frequency shift was negligible

Carl Pettiford; Saumitro Dasgupta; Jin Lou; Soack D. Yoon; N. X. Sun

2007-01-01

104

Low Temperature Heteroepitaxial Growth of a New Phase Lead Zirconate Titanate Film on Si Substrate with an Epitaxial (ZrO2)1-x(Y2O3)x Buffer Layer  

NASA Astrophysics Data System (ADS)

We investigated the crystalline and electrical properties of heteroepitaxial lead zirconate titanate (PZT) films grown on Si covered with epitaxial (100) (ZrO2)1-x(Y2O3)x (YSZ) buffer layers. The PZT films were prepared by reactive sputtering. When the substrate temperature was between 400 and 485\\circC, we obtained a heteroepitaxial (110) oriented monoclinic PZT (m-PZT) film which was metastable. The lattice parameters were as follows: a=b=0.379 nm, c= 0.521 nm and ?=81.3\\circ. The m-PZT film had a larger oxygen composition ratio O/(Zr+Ti) of 3.2 to 3.8 than the perovskite phase. Although the resistivity of the as-grown m-PZT film was much lower than that of the normal perovskite phase, it was increased by two to five orders of magnitude by a step-annealing process of 300\\circC for 120 min, 325\\circC for 120 min and 350\\circC for 180 min in sequence. From the C-V characteristics of the step-annealed m-PZT/YSZ/Si structure, the relative dielectric constant was estimated to be about 45.

Horita, Susumu; Aikawa, Mami; Naruse, Tetsuya

2000-08-01

105

Poling characteristics of PZT\\/epoxy piezoelectric paints  

Microsoft Academic Search

Piezoelectric paints were prepared using lead zirconate titanate (PZT) ceramic powder as a pigment and epoxy resin as a binder. The PZT\\/epoxy composition was adjusted to 92\\/8 or 96\\/4 by weight in the pigment paste (an intermediary product of the final paint), while in the final paint the composition was adjusted to 88\\/12 by weight (53\\/47 by volume) for both

Shigenori Egusa; Naozumi Iwasawa

1993-01-01

106

Effects of strontium substitution in Nb-doped PZT ceramics  

Microsoft Academic Search

Nb-doped lead zirconate titanate (PZT) compositions (2.4 mol%) close to the morphotropic phase boundary (MPB) were investigated systematically as a function of Sr doping as well as Zr:Ti ratio. Sr substitution for Pb in PZT shifted compositions away from the MPB toward the tetragonal phase, greatly reducing the Curie temperature and broadening the dielectric constant maximum, but also decreasing the

H Zheng; I. M Reaney; W. E Lee; N Jones; H Thomas

2001-01-01

107

Piezoelectric Properties of PZT Films Prepared by Hydrothermal Method  

Microsoft Academic Search

Lead zirconate titanate (PZT) thin films of 5 mum thick were produced by a hydrothermal method on pure titanium substrates. ZrOCl2-8H2O, Pb(NO3)2 and TiO2 were used as precursors and KOH as a promoter. The hydrothermal synthesis of PZT includes nucleation and crystal growth processes at 120°C or 140°C. The crystallization states were investigated by using scanning electron microscopy and X-Ray

Nobuyoshi Fujiwara; Kazuhiro Kusukawa; Khairunisak Abdul Razak; Wei Gao

2006-01-01

108

Local ferroelectric properties in polyvinylidene fluoride/barium lead zirconate titanate nanocomposites: Interface effect  

NASA Astrophysics Data System (ADS)

The local piezoelectric properties of ferroelectric composites consisting of P(VDF-TrFE) copolymer matrix with barium lead zirconate titanate ceramic inclusions were addressed both experimentally using piezoresponse force microscopy technique and theoretically applying the Landau-Ginzburg-Devonshire formalism. A transient region with a width of approximately 40 nm has been found at the interface between the two constituents. It is shown that the piezoresponse in the vicinity of the interface is strongly affected by inhomogeneous stresses originating from an incompatibility of thermal expansion coefficients of PVDF and lead zirconate titanate.

Silibin, M. V.; Solnyshkin, A. V.; Kiselev, D. A.; Morozovska, A. N.; Eliseev, E. A.; Gavrilov, S. A.; Malinkovich, M. D.; Lupascu, D. C.; Shvartsman, V. V.

2013-10-01

109

Sol-gel PZT and Mn-doped PZT thin films for pyroelectric applications  

Microsoft Academic Search

Thin films of ferroelectric lead zirconate titanate (PbZr0.3Ti0.7O3 PZT30\\/70) and manganese-doped lead zirconate titanate ((Pb(Zr0.3Ti0.7)1- xMnx)O3, where x = 0.01, PM01ZT30\\/70; and x = 0.03, PM03ZT30\\/70) have been prepared using sol-gel processing techniques. These materials can be used as the pyroelectric thin films in uncooled infrared detectors. The thin films were prepared via a sol-gel route based on a hybrid

Q. Zhang; R. W. Whatmore

2001-01-01

110

Sol-gel PZT and Mn-doped PZT thin films for pyroelectric applications  

Microsoft Academic Search

Thin films of ferroelectric lead zirconate titanate (PbZr0.3Ti0.7O3 PZT30\\/70) and manganese doped lead zirconate titanate ((Pb(Zr0.3Ti0.7)1?xMnx)O3? x = 0.01, PM01ZT30\\/70 and x = 0.03, PM03ZT30\\/70) have been prepared using sol-gei processing techniques. These materials can be used as the pyroelectric thin films in uncooled infrared (IR) detectors. Films deposited on Pt\\/Ti\\/SiO2\\/Si substrates and annealed on a hot plate at 530°C

Q. Zhang; R. W. Whatmore

2001-01-01

111

A cylindrical micro ultrasonic motor using PZT thin film deposited by single process hydrothermal method (?2.4 mm, L=10 mm stator transducer)  

Microsoft Academic Search

A micro ultrasonic motor using PZT (lead zirconate titanate) thin film has been improved by a single process hydrothermal method. The hydrothermal method is a unique method for depositing PZT thin film in a solution. An earlier reported hydrothermal method consisted of two linked processes. Our new method, however, has only a single process. Hence, less distribution of chemical components

Takeshi Morita; Minoru Kuribayashi Kurosawa; Toshiro Higuchi

1998-01-01

112

STUDIES OF SOME DOPANTS: EFFECT OF Mn, Mg, F on (Ba, Sr)PZT FILMS PIEZOELECTRIC RESPONSE FOR SPECIFIC MEMS APPLICATIONS  

Microsoft Academic Search

For its use in power transducers for sonars, ultrasonic welding or cleaning systems, PZT is often subjected to high mechanical or temperature resulting in a depolarisation of the material and thus in a decrease of its performances. To avoid non-linearity and stabilised its properties under these conditions, several dopants have been introduced on barium (Ba)-strontium (Sr) lead zirconate titanate (PZT)

Thu Trang Nguyen; M. Detalle; D. Rémiens; L. Lebrun; D. Guyomar

2008-01-01

113

Preparation of Lead Zirconate Titanate Thin Film by Hydrothermal Method  

Microsoft Academic Search

A hydrothermal method for preparing thin films of crystalline PZT was developed by controlling the rates of nucleation and crystal growth. This method consisted of two steps of hydrothermal reaction. The first step (nucleation process) was that in which the TiO2 substrate reacted with the mixed solution of Pb and Zr to form PZT and\\/or PZ nuclei on the surface.

Katsuhiko Shimomura; Takaaki Tsurumi; Yoko Ohba; Masaki Daimon

1991-01-01

114

Heats of Transformation at the Curie Point in the Lead Titanate-Lead Zirconate System.  

National Technical Information Service (NTIS)

The phase transformation at the Curie point in the lead titanate-lead zirconate system was studied by determining the heats of transformation and the changes in crystal structure in the transformation. This work was confined to the titania rich portion of...

J. E. Playter

1969-01-01

115

Fabrication of lead zirconate titanate ceramic fibers by gelation of sodium alginate  

Microsoft Academic Search

A novel ceramic fiber processing method by gelation of Na-alginate, a natural innoxious polymer, is reported. The ion exchange reaction between Na and Ca, and associated gelation process is utilized to fabricate lead zirconate titanate piezoelectric ceramic fibers using a Na-alginate based ceramic suspension. Effects of solid loading, viscosity of the starting sodium alginate and its amount in the slurry,

Sedat Alkoy; Hakan Yanik; Bengu Yapar

2007-01-01

116

Raman study of lead zirconate titanate under uniaxial stress  

SciTech Connect

The authors used micro-Raman spectroscopy to monitor the ferroelectric (FE) to antiferroelectric (AFE) phase transition in PZT ceramic bars during the application of uniaxial stress. They designed and constructed a simple loading device, which can apply sufficient uniaxial force to transform reasonably large ceramic bars while being small enough to fit on the mechanical stage of the microscope used for Raman analysis. Raman spectra of individual grains in ceramic PZT bars were obtained as the stress on the bar was increased in increments. At the same time gauges attached to the PZT bar recorded axial and lateral strains induced by the applied stress. The Raman spectra were used to calculate an FE coordinate, which is related to the fraction of FE phase present. The authors present data showing changes in the FE coordinates of individual PZT grains and correlate these changes to stress-strain data, which plot the macroscopic evolution of the FE-to-AFE transformation. Their data indicates that the FE-to-AFE transformation does not occur simultaneously for all PZT grains but that grains react individually to local conditions.

TALLANT, DAVID R.; SIMPSON, REGINA L.; GRAZIER, J. MARK; ZEUCH, DAVID H.; OLSON, WALTER R.; TUTTLE, BRUCE A.

2000-04-01

117

Phase Formation in PZT Phosphorus-Doped Ceramics  

SciTech Connect

The surface modification of lead zirconate titanate (PZT) ceramics with phosphate ester leaves a phosphorus residue absorbed onto the particle surface. During the sintering processes, this surface layer reacts with the PZT to form lead-rich compounds, such as Pb{sub 3}(PO{sub 4}){sub 2} and Pb{sub 4}(P{sub 2}O{sub 9}). The formation of such a compounds may be the responsible for the grain growth inhibition observed in PZT-modified ceramics, as well as the lead loss reduction.

Celi, L. A. [Departamento de Fisica, Escuela Politecnica Nacional, Quito (Ecuador); Caballero, A. C.; Villegas, M.; Moure, C.; Fernandez, J. F. [Departamento de Electroceramica, Instituto de Ceramica y Vidrio, Madrid (Spain); Eiras, J. A. [Universidad Federal de Sao Carlos, Departamento de Fisica, Grupo de Ceramicas, Sao Paulo (Brazil)

2009-04-19

118

Dielectric Properties of PVDF/PZT  

SciTech Connect

Poly(vinylidene fluoride)/ lead zirconate titanate nanocomposite (PVDF/PZT-NPs) were successfully prepared by mixing fine Pb(Zr{sub 0.52}, Ti{sub 0.48})O{sub 3} nanoparticles (PZT-NPs) into a PVDF solution under ultrasonication. The mixture was spin coated onto glass substrate and then annealed at 80 deg. C. X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) were used to characterize the structure and properties of the obtained thin-film nanocomposites. The nanocomposites exhibited good dielectric stability over a wide frequency range.

Zak, A. Khorsand; Chen, Gan Wee; Majid, W. H. Abd. [Low dimensional material research center, Department of physics, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia)

2011-03-30

119

Structure and CV characteristics of PZ\\/PZT multilayer thin films (in PZ\\/PZT series sequences) prepared by sol-gel technique  

Microsoft Academic Search

Lead Zirconate (PbZrO3: PZ) and Lead Zirconium Titanate (PZT) multilayered thin films were prepared by sol-gel technique. Sets of films (each layer has a 450Å thickness) made by one PZ after one PZT layer are deposited 3 times successively. These films were annealed just one time after full deposition. Two another sets of films were prepared with the same sequences

Se-Hwan Bae; Kie-Beom Jeon; Sung-Chul Kim; Byung-Moon Jin

2001-01-01

120

Determination of metal impurities in advanced lead zirconate titanate ceramics by axial view mode inductively coupled plasma optical emission spectrometry.  

PubMed

An inductively coupled plasma optical emission spectrometry quantification method for the determination of Al, Ca, Cr Cu, Fe, Mn, Mg, Ni, Zn, Ba, K, In and Co in lead zirconate-titanate (PZT) ceramics, modified with strontium and chromium, was developed. Total digestion of ceramics was achieved with a HNO(3), H(2)O(2) and HF (ac) mixture by using a microwave furnace. The sensitivity of the net signal intensity respect to radiofrequency power (P) and nebulizer argon flow (F(N)) variations was strongly dependent of the total excitation energy of line (TEE). For lines with TEE near metastable atoms and ions of argon, an increment of the sensitivities to P and F(N) variation was observed. At robust plasma conditions the matrix effect was reduced for all matrices and analytes considered. The precision of analysis ranged from 3 to 13%, whereas the analytes recoveries in the spiked samples varied, mostly, from 90 to 110%. The detection limits of studied elements were from 0.004 to 10 mg kg(-1). PMID:22608413

Villanueva Tagle, M E; Larrea Marín, M T; Martin Gavilán, O; Durruthy Rodríguez, M D; Calderón Piñar, F; Pomares Alfonso, M S

2012-03-01

121

Cation ordering in epitaxial lead zirconate titanate films  

NASA Astrophysics Data System (ADS)

Electron diffraction and atom location by channeling enhanced microanalysis were used to show that epitaxial PbZr0.2Ti0.8O3 films grown on (001) SrTiO3 substrates by pulsed laser deposition exhibit long-range order on the tetravalent cation sublattice parallel to the film/substrate interface. This ordering gives two distinct tetravalent cation sites, one Zr lean and one Zr rich, and results in a superlattice with a tetragonal unit cell with lattice parameters a0~?2aPZT and c0~aPZT. Since such ordered states are inherently unstable in homovalent perovskite solutions, it is inferred that the ordering arises in response to the lattice misfit and could constitute an additional relaxation mode.

Zhang, L. C.; Vasiliev, A. L.; Misirlioglu, I. B.; Ramesh, R.; Alpay, S. P.; Aindow, M.

2008-12-01

122

Structural and functional properties of screen-printed PZT–PVDF-TrFE composites  

Microsoft Academic Search

Thick films of 0–3 composites of lead–zirconate–titanate (PZT) particulate and polyvinylidene-trifluoroethylene (PVDF-TrFE) copolymer have been produced by screen-printing on indium–tin-oxide (ITO)-coated glass substrates. The microstructure was investigated using scanning electron microscopy and X-ray diffraction. The dependences of the dielectric properties of the composites on PZT volume fraction are reported and analyzed in terms of an analytical model. The pyroelectric properties

Matthias Dietze; Mohammed Es-Souni

2008-01-01

123

Interdiffusion reaction in the PZT\\/PNN functionally gradient piezoelectric ceramic materials  

Microsoft Academic Search

The interfacial diffusion reaction between lead zirconate titanate (PZT) and lead nickel niobate (PbNi1\\/3Nb2\\/3O3:PNN) phases in the PZT\\/PNN functionally gradient piezoelectric ceramics were investigated as a function of the diffusion temperature and time, respectively. The ionic composition distribution profiles in the interdiffusion region were examined by electron probe microbeam analysis (EPMA). Based on a diffusion model of the overlapped diffusion

XINHUA ZHU; JIE XU; ZHONGYAN MENG

1998-01-01

124

Field forced antiferroelectric-to-ferroelectric switching in modified lead zirconate titanate stannate ceramics  

Microsoft Academic Search

Electric-field-forced antiferroelectric- to-ferroelectric phase transitions in several compositions of modified lead zirconate titanate stannate antiferroelectric ceramics are studied for ultra-high-field-induced strain actuator applications. Two types of fatigue effects are observed in these ceramic compositions. In one, the fatigue effects only proceed to a limited extent and the properties may be restored by annealing above the Curie temperature, while in the

Wuyi Pan; Qiming Zhang; Amar Bhalla; Leslie E. Cross

1989-01-01

125

Bistable optical information storage using antiferroelectric-phase lead lanthanum zirconate titanate ceramics  

Microsoft Academic Search

A recently discovered photostorage effect in antiferroelectric-phase (AFE-phase) lead lanthanum zirconate titanate (PLZT) compositions appears to be particularly applicable to binary optical information storage. The basis for bistable optical information storage is that exposure to near-UV or visible light shifts the electric field threshold of the phase transition between the field-induced ferroelectric (FE) phase and the stable AFE phase in

CECIL E. LAND

1988-01-01

126

Internal friction study on low-temperature phase transitions in lead zirconate titanate ferroelectric ceramics  

Microsoft Academic Search

In this work, a bulk thermodynamics and microstructure study of lead zirconate titanate ferroelectric PbZr0.52Ti0.48O3 is performed through internal friction, Young's modulus, differential scanning calorimetry (DSC), and electron diffraction measurements. Two internal friction peaks are observed near 261 and 225 K. The former correlates with an enthalpy change revealed by DSC data and is ascribable to a first-order tetragonal-to-monoclinic phase

Y. R. Dai; P. Bao; H. M. Shen; D. Su; J. S. Zhu; Y. N. Wang; Y. P. Zhu

2003-01-01

127

Lead zirconate titanate nanowire textile nanogenerator for wearable energy-harvesting and self-powered devices.  

PubMed

Wearable nanogenerators are of vital importance to portable energy-harvesting and personal electronics. Here we report a method to synthesize a lead zirconate titanate textile in which nanowires are parallel with each other and a procedure to make it into flexible and wearable nanogenerators. The nanogenerator can generate 6 V output voltage and 45 nA output current, which are large enough to power a liquid crystal display and a UV sensor. PMID:22713250

Wu, Weiwei; Bai, Suo; Yuan, Miaomiao; Qin, Yong; Wang, Zhong Lin; Jing, Tao

2012-06-22

128

Injection-molded PZT actuators  

NASA Astrophysics Data System (ADS)

Ceramics injection molding technology is being adapted for the fabrication of net shape piezoelectric actuators of lead zirconate titanate (PZT) and lead magnesium niobate (PMN). INjection molding offers low cost, high quality actuator components with a high degree of part-of-part reproducibility. Configurations under investigation include a proprietary high displacement linear element, air acoustic actuators, tube array actuators, benders, and various multilayer designs. Applications include conformable unidirectional patches for active noise and vibration control, high displacement bender actuators for active vortex generators and synthetic jets, high force-high displacement actuators for rotorblade flaps, and air acoustic actuators for active noise reduction.

Near, Craig D.; Schmidt, Gerald; McNeal, Kelley; Gentilman, Richard L.

1998-06-01

129

Integration of PLZT and BST family oxides with GaN[Lead Lanthanum Zirconate Titanate, Barium Strontium Titanate  

SciTech Connect

Recent advances in the processing of complex-oxide materials has allowed the authors to monolithically grow ferroelectrics of lead lanthanum zirconate titanate (PLZT) and barium strontium titanate (BST) systems on a GaN/sapphire structure. High quality films of PLZT and BST were grown on GaN/c-Al{sub 2}O{sub 3} in a thickness range of 0.3--5 {micro}m by a sol-gel technique. Field-induced birefringence, as large as 0.02, was measured from a PLZT layer grown on a buffered GaN/sapphire structure. UV illumination was found to result in more symmetrical electrooptic hysteresis loop. BST films on GaN demonstrated a low frequency dielectric constant of up to 800 with leakage current density as low as 5.5 {center_dot} 10{sup {minus}8} A/cm{sup 2}.

Osinsky, A.V.; Fuflyigin, V.N.; Wang, F.; Vakhutinsky, P.I.

2000-07-01

130

Pulsed laser deposition of nanocrystalline lead zirconate titanate thin films  

NASA Astrophysics Data System (ADS)

Nanocrystalline ferroelectric thin films are obtained by pulsed laser deposition from a target prepared by sintering at approximately 700 °C nanosized powders of Pb(Zr0.52Ti0.48)O3 (PZT) with 1% weight addition of Nb2O2. The powder was prepared by spray-drying and it was calcinated at 500 °C. Film deposition is performed on Si(100) and Au/Si(100) substrates in a reactive oxygen atmosphere using a pulsed Nd-YAG laser with energy 0.3 J/pulse, wavelength 1064 nm, pulse duration 10 ns and frequency 10 Hz. The film samples are investigated by scanning electron microscopy (SEM), x-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and dielectric measurements. The crystallite dimension of PZT films has been found through morphological analysis to be about 30-40 nm. A broadening of the dielectric constant peak at the ferroelectric transition temperature due to finite-size effects is observed. The critical coefficient ? in the Curie-Weiss law is found to be 1.85 which is indicative of a partially diffused phase transition.

Craciun, F.; Dinescu, M.; Verardi, P.; Galassi, C.

1999-03-01

131

Piezoelectric Composite Materials for Ultrasonic Transducer Applications. Part I: Resonant Modes of Vibration of PZT Rod-Polymer Composites  

Microsoft Academic Search

Abstmcr-The objective of the present work was to gain a deeper mensions of the transducer are much smaller than the understanding of the behavior of lead zirconate titanate (PZT) polymer composites for applications such as ultrasonic medical diagnosis in the megahertz frequency range. These composites were originally developed for low-frequency hydrophone applications. The PZT rod-polymer composites have been prepared with

T. R. Gururaja; WALTER A. SCHULZE; LESLIE E. CROSS; ROBERT E. NEWNHAM; BERTRAM A. AULD; YUZHONG J. WANG

1985-01-01

132

Microstructural and optical characterization of PZT nanopowder prepared at low temperature  

NASA Astrophysics Data System (ADS)

Lead zirconate titanate (PZT) nanopowders were synthesized by the metal organic and salt precursor's sol-gel combustion technique. Single-phase perovskite PZT powders were obtained after heat treatment at temperature of 500 °C. The effects of calcination temperature on lattice parameters and tetragonality of PZT powders have been discussed. The average particles size is estimated to be around 70-80 nm by SEM observations. The absorption coefficient (?) and the band-gap energy (Eg) of the perovskite oxide have been estimated using Fourier transform infrared (FTIR) spectroscopy.

Ghasemifard, M.; Hosseini, S. M.; Khorsand Zak, A.; Khorrami, Gh. H.

2009-01-01

133

Electrical characteristics of ferroelectric PZT thin films for DRAM applications  

Microsoft Academic Search

Ferroelectric lead zirconate titanate (PZT) films with as much as 2.5 times the storage capacity of the best reported silicon oxide\\/nitride\\/oxide (ONO) stacked dielectrics have been fabricated. A 2000-Å film with an effective SiO2 thickness of 10 Å is demonstrated. Because of the extremely high dielectric constant (?r≳>1000), even larger storage capacities can be obtained by scaling the ferroelectric film

Reza Moazzami; Chenming Hu; William H. Shepherd

1992-01-01

134

Piezoresponse of Nb-Doped PZT Ceramic and its Application  

Microsoft Academic Search

In this investigation, modified lead zirconate titanate (PZT) piezoceramics with a composition Zr\\/Ti=53\\/47 containing 1 mole% Nb were prepared by conventional ceramic technology sintering powder compacts. Modified ceramics were explored as a function of firing temperature to acquire exceedingly good piezoelectric characterizations. Under the processing conditions, calcined at 850degC for 2 h, and then sintered at 1250degC for 2 h,

Bing Huei Chen; Long Wu; Yuan Bin Chen

2007-01-01

135

Electron-microscope study of lanthanum-doped lead zirconate-titanate solid solutions  

SciTech Connect

This paper examines the structure of specimens of lanthanumdoped lead zirconate-titanate solid solutions in the hysteresis region of the phase diagram, using transmission electron microscopy. The electron-microscopic images of PLZT ceramic of composition display an unusual diffraction contrast. An analysis of the images obtained for different orientations of the cleavages of specimens of composition indicate that the second-phase inclusions are cylindrical in the main. The authors hypothesize that the inclusions are a ferroelectric phase in an antiferroelectric matrix.

Ishchuk, V.M.; Presnyakova, O.V.

1985-12-01

136

Preparation of antiferroelectric lead zirconate titanate stannate ceramics by high-energy ball milling process  

Microsoft Academic Search

Lead zirconate titanate stannate powders doped with lanthanum and niobium, namely [Pb0.99Nb0.02(Zr0.85Sn0.13Ti0.02)0.98O3, or PNZST) and (Pb0.9La0.02(Zr0.65Sn0.31Ti0.04)O3, or PLZST], were synthesized by a high-energy ball milling technique from their corresponding oxide mixtures. The milled powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and particle size analysis techniques. The sintering behaviors of the milled powders were investigated by a

L. B. Kong; J. Ma; T. S. Zhang; W. Zhu; O. K. Tan

2002-01-01

137

Field forced antiferroelectric-to-ferroelectric switching in modified lead zirconate titanate stannate ceramics  

SciTech Connect

Electric-field-forced antiferroelectric- to-ferroelectric phase transitions in several compositions of modified lead zirconate titanate stannate antiferroelectric ceramics are studied for ultra-high-field-induced strain actuator applications. Two types of fatigue effects are observed in these ceramic compositions. In one, the fatigue effects only proceed to a limited extent and the properties may be restored by annealing above the Curie temperature, while in the other, the fatigue effects proceed to a large extent and the properties cannot be restored completely by heat treatment.

Pan, W.; Zhang, Q.; Bhalla, A.; Cross, L.E. (Materials Research Lab., Pennsylvania State Univ., University Park, PA (US))

1989-04-01

138

Bistable optical information storage using antiferroelectric-phase lead lanthanum zirconate titanate ceramics  

SciTech Connect

A recently discovered photostorage effect in antiferroelectric-phase (AFE-phase) lead lanthanum zirconate titanate (PLZT) compositions appears to be particularly applicable to binary optical information storage. The basis for bistable optical information storage is that exposure to near-UV or visible light shifts the electric field threshold of the phase transition between the field-induced ferroelectric (FE) phase and the stable AFE phase in the direction of the initial AFE /yields/ FE phase transition. Properties of this photoactivated shift of the FE /yields/ AFE phase transition, including preliminary photosensitivity measurements and photostorage mechanisms, are presented. Photosensitivity enhancement by ion implantation is also discussed.

Land, C.E.

1988-11-01

139

Dielectric loss peak due to platinum electrode porosity in lead zirconate titanate thin-film capacitors  

NASA Astrophysics Data System (ADS)

Impedance spectroscopy measurements were carried out in situ on lead zirconate titanate capacitors 1.2×1.2 ?m2 in size on a Samsung 4 Mbit 6 in, wafer. We show here that large dielectric loss appears at low frequencies, which is a constriction effect due to the porosity of the platinum electrode. Porous platinum electrodes facilitate an oxygen electrode reaction. The effect may be removed by annealing the platinum electrode at moderate temperature (300 °C). Such an anneal should thus be considered an essential step in the fabrication of a ferroelectric thin-film capacitor on Pt.

Jung, D. J.; Dawber, M.; Ruediger, A.; Scott, J. F.; Kim, H. H.; Kim, Kinam

2002-09-01

140

Strong magnetoelectric coupling at microwave frequencies in metallic magnetic film/lead zirconate titanate multiferroic composites  

NASA Astrophysics Data System (ADS)

Strong magnetoelectric coupling was observed at microwave frequencies in metallic magnetic film/lead zirconate titanate [Pb(Zr,Ti)O3] multiferroic composites, in which the magnetic films were either FeCoB or FeGaB with relatively high saturation magnetostriction constants between 40 and 70 ppm and narrow ferromagnetic resonance linewidths of ~20 Oe at 10 GHz. Large electrostatically induced ferromagnetic resonance frequency shifts of 50-110 MHz at ~2.3 GHz were observed. These metallic magnetic film/Pb(Zr,Ti)O3 multiferroic composites with large electrostatic tunability of the ferromagnetic resonance frequency provide great opportunities for integrated microwave multiferroic devices.

Pettiford, C.; Lou, J.; Russell, L.; Sun, N. X.

2008-03-01

141

Electro-optic effects in thin-film lanthanum-doped lead zirconate titanate.  

PubMed

We report the deposition and characterization of highly oriented thin-film lanthanum-doped lead zirconate titanate (28/0/100) on fused-silica substrates by rf planar magnetron sputtering. The quadratic electro-optic effect gives a birefringence of Deltan ~ 0.018 at an applied field of 39 kV/mm. Optical modulation at a switching speed of 3 nsec (instrumentation limited) is achieved. Results of optically induced decay of the birefringence in these films are also reported. PMID:19759740

Mukherjee, A; Brueck, S R; Wu, A Y

1990-02-01

142

Deaging of heat-treated iron-doped lead zirconate titanate ceramics  

SciTech Connect

Doping strongly influences the properties of ferroelectric perovskite materials. One striking difference between donor- and acceptor-doped materials is the transition from 'soft' to 'hard' ferroelectric behavior. The physical reasons for this phenomenon are still unclear. The authors present measurements of the ferroelectric hysteresis and deaging behavior of iron-doped lead zirconate titanate after adjusting the defect structure by heat treatment in an oxygen-depleted atmosphere. Contrary to expectations, the introduction of extra oxygen vacancies makes the material 'softer' .This effect, which is discussed based on a model of defect dipoles, sheds new light on the unsolved problem of hardening and aging.

Granzow, T.; Suvaci, E.; Kungl, H.; Hoffmann, M. J. [Institute of Materials Science, TU Darmstadt, 64287 Darmstadt (Germany); Department of Materials Science and Engineering, Anadolu University, 26480 Eskisehir (Turkey); Institute for Ceramics in Mechanical Engineering, Karlsruhe University, 76131 Karlsruhe (Germany)

2006-12-25

143

Dielectric properties of chemically synthesized PLZT and PZT: diffused phase transition and effect of lead non-stoichiometry  

NASA Astrophysics Data System (ADS)

Dielectric and ferroelectric properties of chemically synthesized and sintered lead lanthanum zirconate titanate and lead zirconate titanate discs were studied. The as-burnt powders were directly sintered to 94% and 96% of the theoretical density at 1100 °C and 1200 °C, respectively for lead lanthanumm zirconate titanate (PLZT) and 96.7% at 1100 °C for lead zirconate titanate (PZT). The sintered PLZT samples showed improved dielectric properties whereas PZT showed improved ferroelectric properties compared with the data reported in the literature. Dielectric permittivity at room temperature of the 1100 °C sintered PLZT sample with grain sizes 0.4-1.2 µm was ~5000, at all measured frequencies. Evaporation of PbO from the sample generated micro inhomogeneity, which was detrimental for the dielectric property. A sintered PLZT sample underwent a completely diffused phase transition whereas a sintered PZT sample underwent a partially diffused phase transition. The measured values of remnant polarization of the 1100 °C sintered PZT and PLZT samples were 54.0 and 40.0 µC cm-2, respectively. The coercive fields observed for these samples were 13.3 and 7.7 kV cm-1, respectively.

Roy, Subir; Sarah, P.

2007-08-01

144

EFFECTS OF ELECTRIC FIELD ON THE BIAXIAL STRENGTH OF POLED PZT  

SciTech Connect

The mechanical integrity of piezoelectric ceramics plays a crucial role in the performance and design of lead zirconate titanate (PZT) piezo stack actuators especially as PZT actuators become physically larger and are sought to operate under harsher conditions. The reliable design of such systems demands additional consideration of a number of issues that include electro-mechanical coupling as well as strength-size scaling. This study addresses some of those issues through the use of ball-on-ring (BoR) equibiaxial flexure strength tests of two PZT piezo ceramics. The BoR biaxial flexure tests were conducted with two PZT materials under different electric fields. Fracture surfaces and failure initiations were analyzed using optical and scanning electronic microscopy. The effects of electric fields on the two-parameter Weibull distribution are discussed. These results will serve as input data for future probabilistic reliability analysis of multilayer PZT piezo actuators.

Wang, Hong [ORNL; Wereszczak, Andrew A [ORNL

2007-01-01

145

Preparation of a high-quality PZT thick film with performance comparable to those of bulk materials for applications in MEMS  

NASA Astrophysics Data System (ADS)

High-quality lead zirconate titanate (PZT) thick films have been prepared on silicon substrates by combining PZT-Si bonding and wet-etching technology. The bulk PZT wafer was first bonded to the silicon substrate using a 2 µm thick intermediate layer of epoxy resin with a bonding strength higher than 10 MPa. Then the bulk PZT was thinned by a wet-etching method. The thickness of the final PZT films depends on the etching time. The PZT thick films after being polished showed a surface roughness of about 20 nm (RMS), which can satisfy most of the requirements in MEMS. The prepared PZT thick films show a dielectric constant as high as 2400 below 100 kHz, remnant polarization of 13 µC cm-2, piezoelectric constant d31 of about -280 pm V-1 and Young's modulus of about 63 GPa. The measured electromechanical properties of the PZT thick films were comparable to those of the corresponding bulk ceramics. This approach makes it possible to obtain high-quality PZT films because it separates the PZT wafer fabrication from the target substrate and consequently allows integration of the PZT thick films onto many kinds of substrates. Finally, a self-sensing bulk PZT thick film actuator was fabricated as an example of a basic PZT-Si diaphragm structure that can be used in piezoelectric micropumps, and its sensing and actuating performances were also demonstrated.

Xu, Xiao-Hui; Chu, Jia-Ru

2008-06-01

146

Piezoelectric textures based on poly(vinyl chloride) filled with dispersed lead zirconate titanate (PZT-19)  

NASA Astrophysics Data System (ADS)

This paper reports on the results in investigations into the properties of piezoelectric textured materials that are formed through technological treatment of a mixture of components of dispersed poly(vinyl chloride) and a ferroelectric powder with the application of an external mechanical shear stress and an electric field.

Luchnikov, A. P.; Sigov, A. S.

2009-07-01

147

Pb nanowire formation on Al/lead zirconate titanate surfaces in high-pressure hydrogen  

NASA Astrophysics Data System (ADS)

Piezoelectric systems are well known to degrade in hydrogen because of various mechanisms including loss of polarization, Pb migration into the electrode, and surface blistering. Understanding damage mechanisms is crucial for potential high-pressure applications such as injectors for hydrogen-fueled vehicles. In this paper, we report on a previously unreported form of high-pressure hydrogen damage resulting from growth of surface Pb nanowires from an Al electrode on lead zirconate titanate. Wires were observed with roughly 80 nm diameter and with length that varied between 5 and 100 ?m. Microscopy to characterize the nanowires and ion-scattering measurements to quantify concurrent Pb surface migration and hydrogen absorption effects are described.

Alvine, Kyle J.; Shutthanandan, Vaithiyalingam; Arey, Bruce W.; Wang, Chongmin; Bennett, Wendy D.; Pitman, Stan G.

2012-07-01

148

Electric field induced phase transition of antiferroelectric lead lanthanum zirconate titanate stannate ceramics  

SciTech Connect

The electric field induced phase transition behavior of lead lanthanum zirconate titanate stannate (PLZTS) ceramics was investigated. PLZTS undergoes a tetragonal antiferroelectric (AFE{sub Tet}) to rhombohedral ferroelectric (FE{sub Rh}) phase transition with the application of an electric field. The volume increase associated with this antiferroelectric (AFE){endash}ferroelectric (FE) phase transition plays an important role with respect to actuator applications. This volume increase involves an increase in both transverse and longitudinal strains. The E field at which the transverse strain increases is accompanied by an abrupt jump in polarization. The longitudinal strain, however, lags behind this polarization jump exhibiting a slight decrease at the onset of phase switching. This decoupling was related to the preferentially oriented AFE domain configuration, with its tetragonal c-axis perpendicular to the applied electric field. It is suggested that phase switching involves multiple steps involving both structural transformation and domain reorientation. {copyright} {ital 1997 American Institute of Physics.}

Park, S.; Pan, M.; Markowski, K.; Yoshikawa, S.; Cross, L.E. [Materials Research Laboratory, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

1997-08-01

149

Domain structure-property relations in lead lanthanum zirconate titanate ceramics  

SciTech Connect

The domain structure and dielectric properties as a function of lanthanum concentration and Zr/Ti ratio have been investigated in rhombohedral and tetragonal lead lanthanum zirconate titanate (PLZT) ceramics. Transmission electron microscopy revealed that, with increasing lanthanum concentration and Zr/Ti ratio, the long-range-ordered domains (macrodomains) reduced in width, initially being fine scale (20 nm) striations, but eventually forming a {open_quote}{open_quote}mottled{close_quote}{close_quote} contrast (5 nm), characteristic of a relaxor. Relative permittivity measurements as a function of temperature revealed a correlation between broadening of the dielectric maxima and the onset of relaxor-type behavior with the appearance of the striations and mottled (relaxor) contrast, respectively. {copyright} {ital 1996 Materials Research Society.}

Akbas, M.A.; Reaney, I.M.; Lee, W.E. [Department of Engineering Materials, The University of Sheffield, Sheffield, S1 3JD (United Kingdom)

1996-09-01

150

Enhancement of spontaneous polarization in lead zirconate titanate thin films by Dy3+ substitution  

NASA Astrophysics Data System (ADS)

Spontaneous polarization can be enhanced by increasing the crystal anisotropy of tetragonal Pb(Zr,Ti)O3 [PZT] lattice by Zr and Ti-site substitution with Dy3+ cations. Spontaneous polarization (Ps) in epitaxial film of 2% Dy3+-substituted tetragonal Pb(Zr0.40Ti0.60)O3 [Dy-PZT] was compared with that of nonsubstituted Pb(Zr0.40Ti0.60)O3 [PZT] to investigate intrinsic contribution of the Dy3+ substituion to the Ps improvement. Epitaxial thin films of PZT and Dy-PZT with (111) orientations were grown on (111)cSrRuO3//(111)Pt//(100)YSZ//(100)Si substrates by chemical solution deposition. The saturated polarization values of PZT and Dy-PZT films with (111) orientation were 41 and 48 ?C/cm2, respectively. The estimated Ps values of PZT and Dy-PZT films from the saturation polarization values were 71 and 84 ?C/cm2, respectively. The Ps value of this PZT was in good agreement with previous reports. The increase in Ps of the epitaxial Dy3+-substituted PZT film is attributed to the enhancement of the crystal anisotropy, i.e., tetragonality, of the tetragonal PZT lattice. This shows that the enhancement of the ferroelectricity of the tetragonal PZT films can be achieved by ion substitution, just as it can in Bi4Ti3O12-based film.

Nakaki, Hiroshi; Uchida, Hiroshi; Koda, Seiichiro; Okamoto, Shoji; Funakubo, Hiroshi; Nishida, Ken; Katoda, Takashi; Saito, Keisuke

2005-10-01

151

Alternating and direct current field effects on the dielectric response of La-modified lead zirconate titanate  

Microsoft Academic Search

The complex dielectric responses of various La-modified lead zirconate titanate ceramic specimens have been measured under various ac drive and dc bias conditions. Investigations were performed for different La concentrations on specimens with Zr\\/Ti ratios of 40\\/60 and 65\\/35. These investigations demonstrated that the influence of increasing ac drive and dc bias are in opposition: increasing drive results in an

Qi Tan; Dwight Viehland

1997-01-01

152

Calculated dielectric parameters of barium titanate-lead zirconate composites as a function of composition and frequency  

SciTech Connect

Some dielectric parameters e.g., dielectric constant, resistivity, dielectric strength, saturation polarization, loss tangent and coercive field of barium titanate-lead zirconate composites have been calculated as a function of composition and frequency. Most of the dielectric parameters have been found to vary linearly with composition and frequency. A 3-0 connectivity pattern of the composites has been assumed in calculating the dielectric parameters.

Sarkar, S.K. (Microelectronics Section, National Physical Laboratory, New Delhi 110012 (IN))

1990-03-01

153

Raman spectroscopy investigation of the phase transition sequence in lanthanum-modified high zirconium -content lead zirconate titanate ceramics  

Microsoft Academic Search

The phase-transition sequence in lanthanum-modified lead zirconate titanate ceramics with between 0 and 4 at.% lanthanum and a Zr\\/Ti ratio of 92\\/8, (PLZT 100×\\/92\\/8), has been investigated using Raman spectroscopy and dielectric measurements. An antiferroelectric (AFE)-two ferroelectric (FR(LT)) and (FR(HT)) and paraelectric (Pc) phase sequence was confirmed for x<1 at.% La. For x>1%, the coexistence of antiferroelectric (AFE) and ferroelectric

G. Kugel; H. Hassan; J. Handerek; Z. Ujma

1996-01-01

154

Modified Johnson model for ferroelectric lead lanthanum zirconate titanate at very high fields and below Curie temperature  

Microsoft Academic Search

A modified Johnson model is proposed to describe the nonlinear field dependence of the dielectric constant ({var_epsilon}-E loop) in ferroelectric materials below the Curie temperature. This model describes the characteristic ferroelectric 'butterfly' shape observed in typical {var_epsilon}-E loops. The predicted nonlinear behavior agreed well with the measured values in both the low- and high-field regions for lead lanthanum zirconate titanate

M. Narayanan; S. Tong; B. Ma; S. Liu; U. Balachandran

2012-01-01

155

Effects of chemical stability of platinum/lead zirconate titanate and iridium oxide/lead zirconate titanate interfaces on ferroelectric thin film switching reliability  

NASA Astrophysics Data System (ADS)

We report a comparative study focusing on characterization of the ferroelectric film/top electrode interface and electrical measurements, for nominally identical Pb(Zr,Ti)O3 (PZT) films with either Pt or IrO2 top electrodes. We find that the superior reliability and polarization switching behavior of capacitors with IrO2 top electrodes are associated with the inert nature of lead present near the PZT film surface during top electrode processing. In contrast, lead near the PZT surface reacted with the Pt at the film/Pt-top-electrode interface, possibly creating a stable PbxPt1-x phase, and this reaction appeared to cause thickening of a nonferroelectric layer at the PZT/electrode interface.

Chen, Ye; McIntyre, Paul C.

2007-12-01

156

Comparative measurements of piezoelectric coefficient of PZT films by berlincourt, interferometer, and vibrometer methods  

Microsoft Academic Search

Chemical solution deposition (CSD) techniques were used to prepare lead zirconate (Zr) titanate (Ti) (PZT) thin films with Zr\\/Ti ratios of 30\\/70 and 52\\/48. Usually CSD processing is restricted to making crack-free, single-layer films of 70-nm thick, but modifications to the sol-gel process have permitted the fabrication of dense, crack-free, single layers up to 200 to 300 nm thick, which

Zhaorong Huang; Qi Zhang; Silvana Corkovic; Robert Dorey; Roger W. Whatmore

2006-01-01

157

Synthesis of precursors for chemical solution deposition of PZT thin films  

Microsoft Academic Search

Lead zirconate titanate precursors involved in the sol–gel synthesis of PZT thin films were prepared from alkoxides of Pb, Zr and Ti, with the same alcoholic radical (methoxyethoxide), obtained by dehydration and alcoholysis of lead acetate, and by alcoholic exchange of zirconium n-propoxide and titanium ethoxide. In this investigation, 1H and 13C NMR spectroscopic techniques and FTIR analysis have been

R. Caruso; O. de Sanctis; A. Frattini; C. Steren; R. Gil

1999-01-01

158

A micro ultrasonic motor using a micro-machined cylindrical bulk PZT transducer  

Microsoft Academic Search

In this paper, a micro ultrasonic motor using a micro-machined bulk piezoelectric transducer is introduced. The cylindrical shaped bulk piezoelectric transducer, a diameter of 0.8mm and a height of 2.2mm, was developed as stator transducer for traveling wave type ultrasonic motor. The transducer was made of lead zirconate titanate (PZT) bulk ceramics, and formed by micro machining, Ni plating and

Takefumi Kandaa; Akira Makino; Tomohisa Ono; Koichi Suzumori; Takeshi Morita; Minoru Kuribayashi Kurosawac

2006-01-01

159

A cross-junction channel valveless-micropump with PZT actuation  

Microsoft Academic Search

A gas-jet micro pump with novel cross-junction channel has been designed and fabricated using a Si micromachining process.\\u000a The valveless micro pump is composed of a piezoelectric lead zirconate titanate (PZT) diaphragm actuator and fluidic network.\\u000a The design of the valveless pump focuses on a cross-junction formed by the neck of the pump chamber and one outlet and two\\u000a opposite

Van Thanh Dau; Thien Xuan Dinh; Tanaka Katsuhiko; Sugiyama Susumu

2009-01-01

160

New Fabrication of High-Frequency (100-MHz) Ultrasound PZT Film Kerfless Linear Array  

PubMed Central

The paper describes the design, fabrication, and measurements of a high-frequency ultrasound kerfless linear array prepared from hydrothermal lead zirconate titanate (PZT) thick film. The 15-µm hydrothermal PZT thick film with an area of 1 × 1 cm, obtained through a self-separation process from Ti substrate, was used to fabricate a 32-element 100-MHz kerfless linear array with photolithography. The bandwidth at ?6 dB without matching layer, insertion loss around center frequency, and crosstalk between adjacent elements were measured to be 39%, ?30 dB, and ?15 dB, respectively.

Zhu, Benpeng; Chan, Ngai Yui; Dai, Jiyan; Shung, K. Kirk; Takeuchi, Shinichi; Zhou, Qifa

2013-01-01

161

Integration of perovskite PZT thin films on diamond substrate without buffer layer  

NASA Astrophysics Data System (ADS)

Integration of lead zirconate titanate (PZT) thin film on diamond substrate offers a great deal of potential for the application of multifunctional devices under extreme conditions. However, fabrication of perovskite PZT thin films on diamond substrate without a buffer layer has not been realized to date. We report for the first time on the successful deposition of PZT thin film directly on a diamond substrate without any buffer layer using the pulsed-laser deposition technique. The perovskite phase was realized only under specific growth conditions. X-ray diffraction and Raman studies confirmed the perovskite phase. The ferroelectric behaviour of the deposited PZT thin film was confirmed using piezo response microscope phase image and ferroelectric hysteresis loop.

Chandran, Maneesh; Tiwari, Brajesh; Kumaran, C. R.; Samji, Sunil K.; Bhattacharya, S. S.; Ramachandra Rao, M. S.

2012-05-01

162

Energy harvesting using a PZT ceramic multilayer stack  

NASA Astrophysics Data System (ADS)

In this paper, the interdisciplinary energy harvesting issues on piezoelectric energy harvesting were investigated using a ‘33’ mode (mechanical stress and/or electric field are in parallel to the polarization direction) lead zirconate titanate multilayer piezoelectric stack (PZT-Stack). Key energy harvesting characteristics including the generated electrical energy/power in the PZT-Stack, the mechanical to electrical energy conversion efficiency, the power delivered from the PZT-Stack to a resistive load, the electrical charge/energy transferred from the PZT-Stack to a super-capacitor were systematically addressed. Theoretical models for power generation and delivery to a resistive load were proposed and experimentally affirmed. In a quasi-static regime, 70% generated electrical powers were delivered to matched resistive loads. A 35% mechanical to electrical energy conversion efficiency, which is more than 4 times higher than other reports, for the PZT-Stack had been obtained. The generated electrical power and power density were significantly higher than those from a similar weight and size cantilever-type piezoelectric harvester in both resonance and off-resonance modes. In addition, our study indicated that the capacitance and piezoelectric coefficient of the PZT-Stack were strongly dependent on the dynamic stress.

Xu, Tian-Bing; Siochi, Emilie J.; Kang, Jin Ho; Zuo, Lei; Zhou, Wanlu; Tang, Xiudong; Jiang, Xiaoning

2013-06-01

163

Monitoring damage propagation using PZT impedance transducers  

NASA Astrophysics Data System (ADS)

Structural health monitoring (SHM) is of great importance in preventing structural catastrophic failure which can lead to loss of life and property. Lead zirconate titanate (PZT) is one of the most effective types of piezoelectric material, and it has been widely used with the electromechanical impedance (EMI) based SHM technique. In the EMI technique, PZT transducers are surface bonded to a structure to be monitored, and, in the presence of electric fields, they interrogate the structure and record the admittance signatures. The existing EMI techniques have focused on single damage assessment. However, once damage occurs in a structure, it may propagate along a certain direction and eventually lead to failure or collapse of the structure. Therefore, effective monitoring of damage propagation is an important aspect in SHM. This paper presents a study on monitoring damage propagation in aluminium plates using the EMI technique. Experiments are carried out to study the damage propagation by drilling holes in sequence along the length and width directions of the plates. PZT admittance signatures are recorded for each damage state and compared with the signature of the pristine state. In addition, a semi-analytical EMI model is employed to predict the PZT admittance signatures and compare them with the experimental ones. Both experimental and predicted signatures are analysed qualitatively and quantitatively using a statistical method. The results demonstrate the capability of the EMI method for monitoring damage propagation.

Yang, Yaowen; Liu, Hui; Annamdas, Venu Gopal Madhav; Soh, Chee Kiong

2009-04-01

164

Crack tip process zone domain switching in a soft lead zirconate titanate ceramics.  

SciTech Connect

Non-180{sup o} domain switching leads to fracture toughness enhancement in ferroelastic materials. Using a high-energy synchrotron X-ray source and a two-dimensional detector in transmission geometry, non-180{sup o} domain switching and crystallographic lattice strains were measured in situ around a crack tip in a soft tetragonal lead zirconate titanate ceramic. At K{sub 1} = 0.71 MPa m{sup 1/2} and below the initiation toughness, the process zone size, spatial distribution of preferred domain orientations, and lattice strains near the crack tip are a strong function of direction within the plane of the compact tension specimen. Deviatoric stresses and strains calculated using a finite element model and projected to the same directions measured in diffraction correlate with the measured spatial distributions and directional dependencies. Some preferred orientations remain in the crack wake after the crack has propagated; within the crack wake, the tetragonal 0 0 1 axis has a preferred orientation both perpendicular to the crack face and toward the crack front.

Jones, J. L.; Motahari, S. M.; Varlioglu, M.; Lienert, U.; Bernier, J. V.; Hoffman, M.; Ustundag, E.; Univ. of Florida; Iowa State Univ.; The Univ. of New South Wales

2007-09-01

165

Develop techniques for ion implantation of (lead-lanthanum-zirconate-titanate) for adaptive optics  

NASA Astrophysics Data System (ADS)

Research was conducted at Pacific Northwest Laboratory to develop high photosensitivity adaptive optical elements utilizing ion implanted lanthanum-doped lead-zirconate-titanate (PLZT). One centimeter square samples were prepared by implanting ferroelectric and anti-ferroelectric PLZT with a variety of species or combinations of species. These included Ne, O, Ni, Ne/Cr, Ne/Al, Ne/Ni, Ne/O, and Ni/O, at a variety of energies and fluences. An indium-tin oxide (ITO) electrode coating was designed to give a balance of high conductivity and optical transmission at near uv to near ir wavelengths. Samples were characterized for photosensitivity; implanted layer thickness, index of refraction, and density; electrode (ITO) conductivity; and in some cases, residual stress curvature. Thin film anti-ferroelectric PLZT was deposited in a preliminary experiment. The structure was amorphous with x-ray diffraction showing the beginnings of a structure at substrate temperatures of approximately 550 C. This report summarizes the research and provides a sampling of the data taken during the report period.

Batishko, C. R.; Brimhall, J. L.; Pawlewicz, W. T.; Stahl, K. A.; Toburen, L. H.

1987-09-01

166

Develop techniques for ion implantation of PLZT (lead-lanthanum-zirconate-titanate) for adaptive optics  

SciTech Connect

Research was conducted at Pacific Northwest Laboratory to develop high photosensitivity adaptive optical elements utilizing ion implanted lanthanum-doped lead-zirconate-titanate (PLZT). One centimeter square samples were prepared by implanting ferroelectric and anti-ferroelectric PLZT with a variety of species or combinations of species. These included Ne, O, Ni, Ne/Cr, Ne/Al, Ne/Ni, Ne/O, and Ni/O, at a variety of energies and fluences. An indium-tin oxide (ITO) electrode coating was designed to give a balance of high conductivity and optical transmission at near uv to near ir wavelengths. Samples were characterized for photosensitivity; implanted layer thickness, index of refraction, and density; electrode (ITO) conductivity; and in some cases, residual stress curvature. Thin film anti-ferroelectric PLZT was deposited in a preliminary experiment. The structure was amorphous with x-ray diffraction showing the beginnings of a structure at substrate temperatures of approximately 550/sup 0/C. This report summarizes the research and provides a sampling of the data taken during the report period.

Batishko, C.R.; Brimhall, J.L.; Pawlewicz, W.T.; Stahl, K.A.; Toburen, L.H.

1987-07-01

167

Effect of compositional variations in the lead lanthanum zirconate stannate titanate system on electrical properties  

SciTech Connect

The purpose of this work was to evaluate the effect of compositional modifications on the electrical properties of lead lanthanum zirconate stannate titanate (PLZST) ceramics, as well as to examine their electrically induced phase-change behavior. Variations in the Ti:Sn ratio were evaluated. Increased Ti{sup 4+} content produced the following: decreased switching field, related to an increased antiferroelectric-ferroelectric (AFE-FE) transition temperature; constant hysteresis ({Delta}E) correlated with a constant temperature of the maximum dielectric constant (T{sub max}); a sharper dielectric-constant maximum peak; and increased room-temperature dielectric constant (K). Variations in the Zr:Sn ratio also were evaluated. Increased Zr{sup 4+} content produced the following: increased hysteresis with increased T{sub max}, decreased maximum dielectric constant, and decreased switching field with increased AFE-FE transition temperature (T{sub AFE-FE}). From these results, with respect to compositional modifications, the AFE-FE switching field (E{sub AFE-FE}) and {Delta}E were observed to be dependent strongly on T{sub AFE-FE} and T{sub max}, respectively. Negligible change existed in the strain achievable at the switching field, which remained constant for all compositions at {approximately}0.16%. The significance of this research was the ability demonstrated to tailor the properties of phase-change materials through compositional modifications.

Markowski, K.; Park, S.E.; Yoshikawa, Shoko; Cross, L.E. [Pennsylvania State Univ., University Park, PA (United States). Materials Research Lab.

1996-12-01

168

Polarization switching of and electron emission from lead lanthanum zirconate titanate ceramics  

SciTech Connect

This paper focuses on understanding the influence of material properties on the complicated ferroelectric (FE) emission process. Three different compositions in the lead lanthanum zirconate titanate (PLZT) system were chosen for study, based on their widely different dielectric and ferroelectric properties: antiferroelectric (AFE) 2/95/5, normal ferroelectric 8/65/35, and nonferroelectric 15/65/35. Repeatable emission was obtained from the 2/95/5 composition, which could also be modulated at high frequency (200 kHz). The fast AFE {r_reversible} FE phase transition is responsible for the FE emission properties of this material, which is supported by the relationship between the switching current and the emission current. Comparatively, FE emission from the 8/65/35 composition degraded rapidly, which was attributed to decreases in the remanent polarization. No emission signal was detected from the 15/65/35 composition, because no switching activity occurs, which can be interpreted as additional evidence that electron emission from the previously mentioned two compositions was indeed a FE emission process.

Zhang, W.; Huebner, W. [Univ. of Missouri, Rolla, MO (United States). Dept. of Ceramic Engineering; Sampayan, S.E. [Lawrence Livermore National Lab., CA (United States); Krogh, M.L. [Allied Signal Federal Mfg. and Technologies, Kansas City, MO (United States)

1999-03-01

169

Effects of compositional modification in lead lanthanum zirconate stannate titanate ceramics on electric energy storage properties  

NASA Astrophysics Data System (ADS)

The effects of compositional modifications on the antiferroelectric (AFE) to ferroelectric (FE) transition of lead lanthanum zirconate stannate titanate, (Pb1-3x/2Lax)(Zr1-v-zSnvTiz)O3 ceramics were used to optimize this material for energy storage. The experimental results show that an increase of Sn4+ respect to Ti4+ increases the coercive field of AFE-FE transition and keeps the hysteresis at the minimal level. This increases both the energy density of material and energy efficiency relative to a linear dielectric. Another advantage of Sn4+ addition was a polarization increase at the switching field. The substitution of Zn4+ for Sn4+ at fixed Ti4+ concentration of 0.1 was, however, undesirable for energy storage applications since this decreased the forward switching field and increased the hysteresis. This lowered both the energy density of the material and energy efficiency. Finally, addition of La3+ was performed and slim hysteresis loops were obtained resulting in energy efficiency of 80.1%. However, the slanted hysteresis behavior with La3+ results in a lower value of the maximum stored energy.

Jo, Hwan R.; Lynch, Christopher S.

2013-04-01

170

Determination of room-temperature creep of soft lead zirconate titanate piezoceramics under static electric fields  

NASA Astrophysics Data System (ADS)

This study focuses on the experimental investigation of the time-dependent effects of a commercial soft lead zirconate titanate material at room temperature. Samples in initially unpoled states were subjected to a cyclic stepwise electric field which was kept constant at different levels for 300 s. Due to ferroelectric domain switching, significant nonlinearity and hysteresis were observed in the overall polarization and strain response. In particular, the material exhibited creep behavior as the applied electric field was held constant over extended periods of time. This creep was caused by microscopic domain switching processes induced gradually during the holding time. The creep was of primary or transient type in nature and depended strongly on the magnitude of the load applied. Most pronounced creep was observed when holding the field close to the coercive field. Logarithmic representation of the polarization or strain versus time curves indicated that the creep behavior could be quantified approximately by the Andrade power law. The creep exponents were determined for different field conditions. The results may help the understanding of the creep mechanism, which in turn provides contributions to improve the performance and reliability of ultrahigh-precision positioning piezoactuators.

Zhou, Dayu; Kamlah, Marc

2005-11-01

171

Bipolar and unipolar electrical fatigue in ferroelectric lead zirconate titanate thin films: An experimental comparison study  

NASA Astrophysics Data System (ADS)

By performing standard positive-up-negative-down, hysteresis-loop and dielectric measurements on the ferroelectric lead zirconate titanate thin-film capacitors subject to bipolar/unipolar electrical cycling, we show that unipolar fatigue is evident though still less severe than bipolar fatigue conducted at the same voltage. That has been attributed to a series of periodic events of polarization backswitching (driven by the residual depolarization field) and switching (driven by the residual applied field) during unipolar electrical cycling, and explained using the LPD-SICI model (LPD-SICI stands for local phase decomposition caused by switching-induced charge injection). The dielectric results have been used to estimate the effective thickness di of the fatigue-induced degraded (pyrochlorelike) interfacial layer after bipolar/unipolar fatigue, which has not been done so far to our best knowledge. The fact that di is still much less than the film thickness even after the most severe bipolar fatigue strongly suggests that polarization fatigue in ferroelectrics is an interface effect, not a bulk one.

Lou, X. J.; Wang, J.

2010-08-01

172

Reaction mechanisms in the formation of lead zirconate titanate solid solutions under hydrothermal conditions  

SciTech Connect

Reaction mechanisms in the formation of PZT solid solution were studied under hydrothermal conditions (Pb/(Zr + Ti) = 1.0 to 1.9, Zr/Ti = 0/10 to 10/0, 1M to 5M KOH, 100C to 220C, 2 h). A yellow tabular crystallite with tetragonal symmetry and Pb/Ti [approx] 2 was formed at 100 to 130C. A PZT crystallite was formed just above 150C. The crystallite was a mixture of Ti-rich PZT and Zr-rich PZT phases. When the temperature and KOH concentration were increased, the composition of the PZT product tended to be homogeneous. The PZT in the morphotropic phase boundary zone was formed at Zr/Ti = 5/5, 5M KOH, 220C, 2h. Neither PbTiO[sub 3] nor PbZrO[sub 3] was detected as a separate phase under the above hydrothermal conditions.

Humin Cheng; Jiming Ma; Bin Zhu; Yuhong Cui (Peking Univ., Beijing (China). Dept. of Chemistry)

1993-03-01

173

Comparison of lead zirconate titanate thin films on ruthenium oxide and platinum electrodes.  

National Technical Information Service (NTIS)

High-resolution and bright- and dark-field transmission electron microscopy are used to characterize and compare the interface structures and microstructure of PZT/RuO(sub 2)/SiO(sub 2)/Si and PZT/Pt/Ti/SiO(sub 2)/Si ferroelectric thin films, with a view ...

L. A. Bursill I. M. Reaney

1994-01-01

174

Structural and magnetoelectric properties of MFe 2 O 4 –PZT (M?=?Ni,Co) and La x (Ca,Sr) 1-x MnO 3 –PZT multilayer composites  

Microsoft Academic Search

Thick-film layered magnetoelectric composites consisting of ferromagnetic and ferroelectric phases have been synthesized with nickel ferrite (NFO), cobalt ferrite, La 0.7Sr 0.3MnO 3 (LSMO), or La 0.7Ca 0.3MnO 3 (LCMO) and lead zirconate titanate (PZT). Structural, magnetic, and ferromagnetic resonance characterization shows evidence for defect-free ferrites, but deterioration of manganite parameters. The resistivity and dielectric constants are smaller than expected

G. Srinivasan; E. T. Rasmussen; A. A. Bush; K. E. Kamentsev; V. F. Meshcheryakov; Y. K. Fetisov

2004-01-01

175

Influence of a Polyimide Surface Layer on the Piezoelectric Response of Lead--Zirconate--Titanate Cosmic Dust Detector  

NASA Astrophysics Data System (ADS)

The influence of a thermal reflector on the sensitivity of a lead--zirconate--titanate element is studied by bombarding the element with hypervelocity microparticles. The reflector is a 60-?m-thick layer made of polyimide resin that coats the surface of the element. By applying the fast Fourier transform method to data analysis, impact information is obtained through the fundamental resonant component. As a result, the sensitivity of the element is considerably reduced by the reflector. In addition, it is found that the sensitivity is substantially position-independent.

Hattori, Maki; Kobayashi, Masanori; Miyachi, Takashi; Takechi, Seiji; Okudaira, Osamu; Iwai, Takeo; Okada, Nagaya; Sugita, Seiji

2013-02-01

176

A combination of PZT and EMAT transducers for interface inspection.  

PubMed

A PZT (Lead Zirconate-Titanate) transducer requires a couplant to send and receive mechanical waves. This requirement is a major shortcoming of the PZT technique for use in field applications. In the laboratory environment careful considerations and surface treatments are required to use PZT because the couplant can affect the consistency of experimental results. One alternative to overcome this shortcoming is the use of EMAT (ElectroMagnetic Acoustic Transducer). However, EMAT gives relatively low transmitted ultrasonic energy, with low signal to noise ratio, and the induced energy is critically dependent on the probe proximity to the test object. These are not desirable properties for NDT (nondestructive testing) of civil infrastructures. That is why, in this paper, a combination of PZT and EMAT is introduced for investigating reinforced concrete structures. Interface defects between steel bars and concrete are investigated by this technique. It is shown that the PZT-EMAT combination is very effective for steel bar-concrete interface inspection and the guided waves are useful for nondestructive testing of civil infrastructures. PMID:12051433

Na, Won-Bae; Kundu, Tribikram

2002-05-01

177

Preisach modelling of nonlinear response in electrically biased lead zirconate titanate-based piezoceramics  

NASA Astrophysics Data System (ADS)

The alteration of the high-field electrical permittivity (nonlinear response) of PZT-based ceramics when an electrical bias field is applied is reported in this work. Large differences are observed between soft and hard PZT behaviours. While in soft PZT a bias field does not modify the nonlinear behaviour, a notable dependence is verified in hard PZT. The Preisach model is satisfactorily used to describe experimental results. A distribution function containing the first terms of the Maclaurin development series of a function composed by two Gaussian-like functions of different amplitudes is proposed. The model gives a satisfactory explanation for the fact that the permittivity depends not only on the amplitude of the applied electric field, but also on the bias field, both for soft and hard ceramics and for poled or unpoled samples.

Ochoa, Diego A.; Pérez, Rafel; García, Jose E.

2013-09-01

178

Improved ferroelectric and pyroelectric properties in Mn-doped lead zirconate titanate thin films  

Microsoft Academic Search

We have investigated the effects of Mn doping on the ferroelectric and pyroelectric properties of Pb(Zr0.3Ti0.7)O3 (PZT) thin films on substrates Pt\\/Ti\\/SiO2\\/Si. The Mn-doped (1 mol %) PZT (PMZT) showed almost no hysteretic fatigue up to 1010 switching bipolar pulse cycles, coupled with excellent retention properties. We present evidence that while a low permittivity interfacial layer forms between the Pt

Q. Zhang; R. W. Whatmore

2003-01-01

179

Nondestructive damage detection and interfacial evaluation of single-fibers\\/epoxy composites using PZT, PVDF and P(VDF-TrFE) copolymer sensors  

Microsoft Academic Search

Damage sensing and interfacial evaluation of single-glass or basalt fibers\\/epoxy composites were performed by micromechanical technique and acoustic emission (AE). Piezoelectric lead–zirconate–titanate (PZT), polyvinylidene fluoride (PVDF) and poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) copolymer were used as AE sensor, respectively. In single-fiber composite, the damage sensing and interfacial properties with different sensor types were compared with each other. Piezoelectric PVDF polymer sensor was

Joung-Man Park; Jin-Woo Kong; Dae-Sik Kim; Dong-Jin Yoon

2005-01-01

180

Sol-gel processing of PZT thin films: A review of the state-of-the-art and process optimization strategies  

Microsoft Academic Search

Sol-gel processing has been widely employed for the fabrication of lead zirconate titanate (PZT) thin films. To successfully optimize thin film material properties for different applications, we must develop a fundamental understanding of the processing-property relationships inherent in the sol-gel fabrication process. In the asprepared state, sol-gel thin films are amorphous, have large organic contents, and can possess significant porosity.

Robert W. Schwartz; Timothy J. Boyle; Steven J. Lockwood; Michael B. Sinclair; Duane Dimos; Catherine D. Buchheit

1995-01-01

181

Study of PZT thick-film infrared detectors prepared by MEMS technology  

NASA Astrophysics Data System (ADS)

In this paper, a single element integrated infrared detector using screen printed lead zirconate titanate (PZT) thick films on Pt/Ti/Al2O3/SiO2 coated silicon cup has been developed. The thermal insulating micro-bridge of the detector was prepared by Micro-electro-mechanical System (MEMS) technology. To increase the density of PZT ceramic thick films, cool isostatic pressing experiments had been conducted under 300MPa and 30s dwell time. The XRD pattern shows that PZT thick films possess good perovskite structure. The SEM cross section image demonstrate that the PZT film was dense and the thickness is about 25?m. The dielectric constant, loss and pyroelectric coefficient of PZT thick films prepared at optimized conditions is 1100, 1% and 1×10-8C/Kcm 2, respectively. The results indicated that the PZT thermal sensitive layer fabricated by screen printing on the Pt/Ti coated silicon cup with micro-bridge thermal insulation structure, and Al2O3/SiO2 barrier layer show potential application in infrared detectors.

Qiang, Xiang-Peng; Chuan, Gui-Wu; Wen, Bo-Luo; Wan, Li-Zhang; Jia, Qiang-Cao

2011-06-01

182

Experimental investigation of domain switching criterion for soft lead zirconate titanate piezoceramics under coaxial proportional electromechanical loading  

NASA Astrophysics Data System (ADS)

In this experimental work, ``soft'' lead zirconate titanate specimens in an initially unpoled state were subjected to combined electromechanical loading, in which a compressive stress and a parallel, proportional electric field were applied simultaneously. By changing the ratio of stress to the electric field between tests, a series of nonlinear polarization and strain responses were obtained. An attempt has been made to explain the experimental findings by simultaneously taking into account the contributions of dielectric response, elastic deformation, piezoeffects, and irreversible domain switching. Initial domain switching surfaces in the biaxial stress and electric field space were determined based on an offset method. Several switching conditions existing in the literature were summarized and compared with the experimental data obtained in this work. Such an investigation may serve to calibrate and validate existing constitutive models concerning the large-signal nonlinear behavior of piezoceramics.

Zhou, Dayu; Wang, Zhenggui; Kamlah, Marc

2005-04-01

183

Dielectric properties of lead lanthanum zirconate titanate thin films with and without ZrO2 insertion layers  

NASA Astrophysics Data System (ADS)

The dielectric properties of lead lanthanum zirconate titanate (PLZT) thin films on platinized silicon (Pt/Si) with and without ZrO2 insertion layers were investigated in the temperature range from 20 °C to 300 °C. Permittivity, dielectric loss tangent, and tunability were reduced for the samples with ZrO2 insertion layers compared to those without the layers. Additionally, the permittivity was less dependent on frequency over the broad temperature range studied (20-300 °C). The leakage current behavior of the PLZT films with and without ZrO2 insertion layers was also investigated, and on the basis of those results, a probable conduction mechanism has been suggested. The improved electrical properties in the PLZT with ZrO2 layers are attributed to the ZrO2 layer blocking the mobile ionic defects and reducing free charge carriers to transport.

Liu, Shanshan; Ma, Beihai; Narayanan, Manoj; Tong, Sheng; Koritala, Rachel E.; Hu, Zhongqiang; Balachandran, Uthamalingam

2013-05-01

184

Deposition and characterization of thin ferroelectric lead lanthanum zirconate titanate (PLZT) films on sapphire for spatial light modulators applications.  

PubMed

Ferroelectric lead lanthanum zirconate titanate (PLZT) films are deposited on R-plane sapphire using RF triode magnetron sputtering. Perovskite PLZT films with the desired composition (9/65/35) are obtained using compensated deposition techniques around 500 degrees C and postdeposition annealing at 650 degrees C. The deposited films exhibit good optical and electrooptical properties. The room temperature dielectric constant of the films was 1800 at 10 kHz. The refractive index of the films was in the range of 2.2-2.5. The films showed a quadratic electrooptic effect with R=0.6 x10(-16) m(2)/V(2). The development of PLZT on silicon-on-sapphire smart spatial light modulators using these films is also explored. PMID:18267622

Krishnakumar, S; Ozguz, V H; Fan, C; Cozzolino, C; Esener, S C; Lee, S H

1991-01-01

185

Microfabrication of PZT force sensors for minimally invasive surgical tools  

NASA Astrophysics Data System (ADS)

Minimally invasive surgery (MIS) is the most exciting and rapidly developing area where force sensing is actually of central importance. Micromachined piezoelectric sensors can be integrated onto MIS tools for improved diagnosis and treatment monitoring. A micro-machined freestanding lead zirconate titanate (PZT) force sensor is fabricated using five masks process incorporating deep reactive ion, ion beam and wet-chemical etching techniques. The PZT sensor is designed as a parallel plate capacitor structure in which the sol-gel prepared 1-µm thick PZT film is sandwiched between top (Au/Cr) and bottom (Pt/Ti) metal electrodes mounted on a thin Si membrane. This paper also describes a new wet chemical approach for patterning PbZr0.52Ti0.48O3 films. The etch recipe provided excellent etch control, minimized undercut, preserved the photoresist mask, and effectively removed the residues on the etched surfaces. A high etch rate (200 nm/min), high selectivity with respect to photoresist, and limited under-cutting (1.5:1, lateral : thickness) were obtained. The fabricated force sensor exhibited good ferroelectric properties. The current fabrication procedure and electrical analysis can be considered as a breakthrough for fabricating freestanding PZT force sensor in any desired shape and dimensions, as well as a good example of ferroelectric microdevices.

Ezhilvalavan, S.; Zhang, Zaoli; Loh, Jeremy; Ying, Jackie Y.

2006-04-01

186

Lamb wave tuning curve calibration with improved PZT modeling  

NASA Astrophysics Data System (ADS)

Guided waves generated and measured using surface-bonded Lead Zirconate Titanate (PZT) transducers have been widely used for structural health monitoring (SHM) and nondestructive testing (NDT) applications. For selective actuation and sensing of Lamb wave modes, the sizes of the transducers and the driving frequency of the input waveform should be tuned. For this purpose, a theoretical Lamb wave tuning curve (LWTC) of a specific transducer size is generally obtained. Here, the LWTC plots each Lamb wave mode' amplitude as a function of the driving frequency. However, a discrepancy between experimental and existing theoretical LWTCs has been observed due to little consideration of the bonding layer and the energy distribution between Lamb wave modes. In this study, calibration techniques for the theoretical LWTCs are proposed. First, a theoretical LWTC is developed when circular shape of PZTs is used for both Lamb wave excitation and sensing. Then, the LWTC is calibrated by estimating the effective PZT size with PZT admittance measurement. Finally, the energy distributions among symmetric and antisymmetric modes are taken into account for better prediction of the relative amplitudes between Lamb wave modes. The effectiveness of the proposed calibration techniques is examined through numerical simulations and experimental estimation of the LWTC using the circular PZT transducers instrumented on an aluminum plate.

Lee, Sang Jun; Sohn, Hoon

2009-03-01

187

Effect of External Vibration on PZT Impedance Signature  

PubMed Central

Piezoelectric ceramic Lead Zirconate Titanate (PZT) transducers, working on the principle of electromechanical impedance (EMI), are increasingly applied for structural health monitoring (SHM) in aerospace, civil and mechanical engineering. The PZT transducers are usually surface bonded to or embedded in a structure and subjected to actuation so as to interrogate the structure at the desired frequency range. The interrogation results in the electromechanical admittance (inverse of EMI) signatures which can be used to estimate the structural health or integrity according to the changes of the signatures. In the existing EMI method, the monitored structure is only excited by the PZT transducers for the interrogating of EMI signature, while the vibration of the structure caused by the external excitations other than the PZT actuation is not considered. However, many structures work under vibrations in practice. To monitor such structures, issues related to the effects of vibration on the EMI signature need to be addressed because these effects may lead to misinterpretation of the structural health. This paper develops an EMI model for beam structures, which takes into account the effect of beam vibration caused by the external excitations. An experimental study is carried out to verify the theoretical model. A lab size specimen with different external excitations is tested and the effect of vibration on EMI signature is discussed.

Yang, Yaowen; Miao, Aiwei

2008-01-01

188

Effects of rare earth metal substituents on the high power piezoelectric properties in lead zirconate titanate-lead (antimony,manganese)O(3) ceramics  

NASA Astrophysics Data System (ADS)

Improved piezoelectric materials with higher vibrational velocities are needed to meet the demands of advanced high power electromechanical applications. In this thesis, the effects of the rare earth (RE) metal substituents on the vibrational velocity, the piezoelectric properties and polarization behavior of Pb(Zr,Ti)O3-Pb(Sb,Mn)O3 ceramics have been investigated. Under high drive levels, the mechanical quality factor and the vibrational velocity were both significantly improved by RE substitution. For a longitudinal vibrator, driven under the d31 mode, root mean square value (rms value) of vibration velocity as high as 0.9 m/s under an electric field of 10 kV/m (rms value) has been found for Yb-substituted specimens, which is 1.5 times higher than that of base Pb(Zr,Ti)O3-Pb(Sb,Mn)O 3 ceramics. For most of rare earth substituents investigated in this system, regardless of the species ionic radii, the piezoelectric properties were observed to have combinative "hard" and "soft" characteristics. "Hard" piezoelectrics have higher Qm values, but lower k31 values. On the other hand, "soft" piezoelectrics have lower Qm values, but higher k31 values. The increased mechanical quality factor Qm (typical of "hard" piezoelectrics) and increased electromechanical coupling coefficient k31 (typical of "soft" ones) were both achieved by RE substitution. With increasing rare earth substituent ionic size, there was no absolute proportional relationship between k31/Qm and dopant ionic size observed. Polarization-electric field (P-E) measurements revealed a significant relaxational polarization similar to a "soft" piezoelectric, in addition to an internal dipolar field similar to a "hard" piezoelectric. A possible explanation for the combinative "hardening" and "softening" effects is the coexistence of randomly quenched and mobile defects. The time dependences after poling of the mechanical quality factor Q m, electromechanical coupling coefficient k31 and dielectric constant K have been investigated for both "soft" and "hard" lead zirconate titanate (PZT) ceramics. A significant increase of Qm with time was observed for "hard" PZTs, however "soft" ones did not exhibit any changes during the same time period. The aging rate after poling was found to be related to the degree of "hard" characteristics. Polarization versus electric field (P-E) measurements of "hard" PZTs revealed the development of a shift of the response along the E axis with time. It is believed that an internal dipolar field develops with time, due to a reorientation of defect dipoles along the direction of spontaneous polarization through oxygen diffusion. (Abstract shortened by UMI.)

Gao, Yongkang

189

Cathodic electrodeposition of mixed oxide\\/hydroxide precursor for lead-zirconate-titanate thin films  

Microsoft Academic Search

The cathodic electrodeposition of thin films greenlings of PbZrxTi1-xO3 (PZT) from an aqueous electrolyte is studied. The principle of the technique is the hydrolization and co-precipitation of soluble ionic titanium-, zirconium- and lead compounds by electrochemical generation of OH- on the substrate electrode. The applied potential or current density, respectively, strongly influence the deposition rate. Layers with a thickness in

A. E. Prodromides; P. Schmuki

1999-01-01

190

First-principles calculations of piezoelectricity and polarization rotation in lead zirconate titanate  

NASA Astrophysics Data System (ADS)

Recent experimental and theoretical work indicates that polarization rotation via a monoclinic phase at the morphotropic phase boundary in PZT is responsible for its large piezoelectric response. We performed Linearized augmented plane wave with the local orbital extension (LAPW+LO) method within local density approximation (LDA) on B-site [001]1:1 ordered Pb(Zr 0.5Ti0.5)O3 (PZT 50/50). We use a tetragonal super-cell and constrain it with monoclinic Cm space group. Atomic forces following the formulation of Yu et al. are calculated, and the conjugate gradient method is implemented to optimize the internal coordinates. Both the tetragonal (P4mm) and monoclinic (Cm) phases are reproduced, when we strain the system while keeping the volume fixed at experimental value. Bulk spontaneous polarization, Born effective charges (Z*) and piezoelectric coefficients are computed from the Berry's phase approach. The polarization rotates between the pseudo-cubic [001] and [nunu1] directions, where nu = 1.27 in the (110) mirror plane. The piezoelectric coefficients are enhanced when polarization rotation is permitted, namely e33 = 12.6 C/m2, e15 = 10.9 C/m 2, and giant absolute values of e13 = -33 C/m 2 and e'11 = 36 C/m2, where e'11, is defined as 0.5 (e11 + e12). It gives an explanation to the big piezoelectric response measured in ceramic PZT 50/50. Furthermore, the calculated internal coordinates of monoclinic phase of PZT 50/50 at experimental value of c/a are in good agreement with the experimental data of Pb(Zr0.52Ti 0.48)O3.

Wu, Zhigang

191

Study of global and local crystallography at the domain boundaries of lead zirconate titanate piezoelectric ceramics  

NASA Astrophysics Data System (ADS)

Reliable automated orientation mapping of 90° domains in a tetragonal perovskite has been achieved for the first time using both EBSD and TEM-Kikuchi pattern analysis. This has been used to compare local measurements of c/a ratios in PZT with global measurements by X-ray diffraction. The local c/a rations are in broad agreement with the global measurements, but further work is needed to determine whether the small discrepancies are real local variations or are caused by experimental factors.

Farooq, M. U.; Villaurrutia, R.; MacLaren, I.; Kungl, H.; Hoffmann, M. J.; Fundenberger, J.-J.; Bouzy, E.

2008-08-01

192

Sensitivity of PZT Impedance Sensors for Damage Detection of Concrete Structures  

PubMed Central

Piezoelectric ceramic Lead Zirconate Titanate (PZT) based electro-mechanical impedance (EMI) technique for structural health monitoring (SHM) has been successfully applied to various engineering systems. However, fundamental research work on the sensitivity of the PZT impedance sensors for damage detection is still in need. In the traditional EMI method, the PZT electro-mechanical (EM) admittance (inverse of the impedance) is used as damage indicator, which is difficult to specify the effect of damage on structural properties. This paper uses the structural mechanical impedance (SMI) extracted from the PZT EM admittance signature as the damage indicator. A comparison study on the sensitivity of the EM admittance and the structural mechanical impedance to the damages in a concrete structure is conducted. Results show that the SMI is more sensitive to the damage than the EM admittance thus a better indicator for damage detection. Furthermore, this paper proposes a dynamic system consisting of a number of single-degree-of-freedom elements with mass, spring and damper components to model the SMI. A genetic algorithm is employed to search for the optimal value of the unknown parameters in the dynamic system. An experiment is carried out on a two-storey concrete frame subjected to base vibrations that simulate earthquake. A number of PZT sensors are regularly arrayed and bonded to the frame structure to acquire PZT EM admittance signatures. The relationship between the damage index and the distance of the PZT sensor from the damage is studied. Consequently, the sensitivity of the PZT sensors is discussed and their sensing region in concrete is derived.

Yang, Yaowen; Hu, Yuhang; Lu, Yong

2008-01-01

193

A Reusable PZT Transducer for Monitoring Initial Hydration and Structural Health of Concrete  

PubMed Central

During the construction of a concrete structure, strength monitoring is important to ensure the safety of both personnel and the structure. Furthermore, to increase the efficiency of in situ casting or precast of concrete, determining the optimal time of demolding is important for concrete suppliers. Surface bonded lead zirconate titanate (PZT) transducers have been used for damage detection and parameter identification for various engineering structures over the last two decades. In this work, a reusable PZT transducer setup for monitoring initial hydration of concrete and structural health is developed, where a piece of PZT is bonded to an enclosure with two bolts tightened inside the holes drilled in the enclosure. An impedance analyzer is used to acquire the admittance signatures of the PZT. Root mean square deviation (RMSD) is employed to associate the change in concrete strength with changes in the PZT admittance signatures. The results show that the reusable setup is able to effectively monitor the initial hydration of concrete and the structural health. It can also be detached from the concrete for future re-use.

Yang, Yaowen; Divsholi, Bahador Sabet; Soh, Chee Kiong

2010-01-01

194

Bolted joint looseness damage detection using electromechanical impedance measurements by PZT sensors  

NASA Astrophysics Data System (ADS)

Bolted joints are of great importance in steel structures. Any levels of looseness or even failure in the bolted joints if not earlier be found in time, will continuously change the connection strength and stiffness, causing cumulative damage to the structure, or even resulting in a sudden structural failure. Thus, it is crucial to develop efficient detection approach for early looseness in bolted joint. In particular, electro-mechanical impedance (EMI)-based damage detection technique which uses smart piezoelectric Lead Zirconate Titanate (PZT) patches has emerged as a potential tool for local damage detection of engineering structures. This paper presents a feasibility study on the application of an EMI-based bolted joint looseness detection with PZT patches. One steel specimen and an aluminum specimen were designed and the bolt looseness damage was introduced by loosening some connection bolts. Impedance measurement for each PZT sensor on the two sides of bolted joint with different distances from the loosened bolts was carried out on. A quantitative identification method based on a statistical damage index, the root mean square deviation (RMSD) of the EMI over different frequency bands, was proposed to assess the presence of damage. Results showed the RMSD can detect the existence of looseness damage and the sensitivity of the PZT sensors are investigated for the bolted joint structure. Also, the sensitive region of the PZT patches in different frequency ranges for both specimens were discussed. The proposed approaches have great potential to be applied in practice for the looseness detection in bolted joints.

Chen, Mengqi; Xu, Bin

2011-11-01

195

Application of Multiplexed FBG and PZT Impedance Sensors for Health Monitoring of Rocks  

PubMed Central

Reliable structural health monitoring (SHM) including nondestructive evaluation (NDE) is essential for safe operation of infrastructure systems. Effective monitoring of the rock components of civil infrastructures such as tunnels and caverns remains challenging. The feasibility of employing smart optical fibre sensor (OFS) and piezoelectric impedance sensor made up of lead zirconate titanate (PZT) for comprehensive health monitoring of rocks, covering load history monitoring/retrieval as well as damage assessment is presented in this paper. The rock specimens are subjected to cyclic loading and their conditions are continuously monitored using OFS and PZT sensors. OFS based multiplexed fibre Bragg grating (FBG) sensors are surface bonded on the rock specimens. Their strain sensing performance is compared with the conventional electric strain gauges (ESGs). In addition, PZT patches are also bonded on the specimens to study the damage pattern during different loading cycles. Unlike the FBGs or ESGs, PZT patches are used as bi-functional sensors and actuators, enabling them to be efficient detectors of incipient damages using the principle of electromechanical impedance. The experimental study demonstrated superior performance of these smart FBG and PZT impedance sensors. This work is expected to be useful for SHM based NDE application of rock structures such as caverns and tunnels.

Yang, Yaowen; Annamdas, Venu Gopal Madhav; Wang, Chao; Zhou, Yingxin

2008-01-01

196

IN SITU Detection of Surface-Mounted PZT Transducer Defects Using Linear Reciprocity  

NASA Astrophysics Data System (ADS)

Guided waves generated by Lead Zirconate Titanate (PZT) transducers are often used to detect structural damage for nondestructive evaluation (NDE) and structural health monitoring (SHM) applications. It is generally assumed that the surface-mounted PZT transducers are both undamaged and properly bonded to the host structure during usage. However, this assumption may not be valid, particularly under realistic operating conditions. In this study, a methodology for PZT transducer diagnosis is developed to identify abnormal transducers using linear reciprocity of guided wave propagation between pairs of surface-mounted transducers on metallic structures. The advantage of the proposed technique is that transducer bonding problems and PZT defects can be detected even when the system being monitored is subjected to varying operational, environmental or structural conditions. In addition, the complexity of the boundary conditions and the geometry of the structure do not affect performance. The effectiveness of this diagnostic technique is evaluated via numerical simulations and experiments with PZT transducers instrumented on an aluminum plate.

Lee, Sang Jun; Sohn, Hoon; Michaels, Jennifer E.; Michaels, Thomas E.

2010-02-01

197

Local damage detection for steel rebar by impedance measurements of PZT sensors  

NASA Astrophysics Data System (ADS)

Steel rebar is the most employed reinforcements in concrete structures and is subjected to damage due to environmental factors. Therefore it is meaningful to develop suitable non-destructive damage detection methods for steel rebar in engineering structures. Lead Zirconate Titanate (PZT) is one of the most effective types of piezoelectric material, and it has been widely used both sensors and transducers for the structural health monitoring (SHM) of engineering structures. Based on the coupling effect of PZT patches surface-bonded on a structural member, the electromechanical impedance (EMI) based structural damage detection has been employed to detect local damage of civil engineering structures. This paper presents the results of the experimental study on the EMI based damage detection for steel rebar specimens under different damage scenarios by analyzing the changes in the piezoelectric admittance spectrum of PZT patches surface-bonded on the steel rebar specimens. A damage index called the root mean square deviation of admittance (RMSDD) is employed to evaluate the extent of damage of the steel beam. Based on the analysis on the relationship between the damage index and the distance of the PZT sensor from the damage, the sensitivity of the PZT sensors and their sensing region is discussed. The results shows that the location and level of the damages could be quantitatively identified by converting the admittance measurements into the scalar damage index.

Kuang, Juan; Xu, Bin

2011-11-01

198

Characterizing reliability of multilayer PZT actuators  

NASA Astrophysics Data System (ADS)

Many new applications are emerging for piezoelectric ceramics including adaptive structures, active-flow-control devices, and vibration and noise suppression systems. Additionally, there are opportunities to use these devices in the biomedical field for miniature pumps, ultrasonic surgical tools, micro-needle arrays, and nanorobotics. In each of these instances, actuator stability is critical, representing a significant challenge for piezoelectric ceramic materials. In particular, the properties of lead zirconate titanate (PZT) have been found to degrade, often significantly, during continuous operation due to a combination of domain pinning, relaxation of interfacial stress, and, in the worst cases, micro-crack formation. This degradation, referred to as actuator fatigue, can be even more pronounced when high voltages are used to achieve maximum displacement or more complex actuator designs are required. For example, multilayer actuators, such as co-fired stacks, are important for many emerging applications and are now being produced with very small physical dimensions, lowering power requirements. However, multilayer components may be highly susceptible to long-term fatigue due to the large number of interfaces involved in their configuration. In this work, we report a method for rapidly characterizing the reliability of multilayer PZT actuators by monitoring degradation in switching polarization over time. To verify this approach, a series of miniature (3 mm x 3 mm x 2 mm) multilayer actuators were characterized over 1 million cumulative cycles. These actuators were produced commercially from soft PZT materials, and the sintering temperature was varied to tailor the ceramic microstructure and performance characteristics. Evaluation of cyclic polarization degradation was found to be an effective method for illuminating differences among the different actuators tested, as well as serving to predict their long-term resistance to fatigue.

Hooker, S. A.

2006-04-01

199

Monitoring damage propagation using PZT impedance transducers  

NASA Astrophysics Data System (ADS)

Lead Zirconate Titanate (PZT) transducers have been extensively used in the electromechanical impedance (EMI) based structural health monitoring (SHM). Many EMI models have been developed for damage assessment, mostly focusing on single damage identification. However, in real life, structures are frequently subjected to multiple or progressive damages. Specifically, structural components such as beams and columns are subjected to loading, vibration, wear and tear which could cause multiple damages. Once damages occur, they usually propagate along certain directions due to continuous usage or inadequate protection. Moreover the increase in severity of damages may lead to failure of the structural components or even the whole structure. The EMI technique which is based on the electromechanical interaction between the PZT transducer and its host structure has been found to be effective in damage detection. However, systematic study on monitoring the progressive of damage in multiple directions in the structures is still in need. In this paper, the EMI technique using surface bonded PZT transducers is employed to obtain the structural health signature. Experimental tests are carried out to study the damage propagation on aluminum plates, where damages are created along the length and width directions of the plates by drilling holes in sequence. Structural health signatures are obtained for each damage state and compared with the signature of non-damage state, followed by the discussion on the characteristics of damage propagation. In addition, for different damaged states, finite element modeling is carried out to verify the experimental signatures. The acquired numerical results are analyzed both qualitatively and quantitatively. Both experimental and numerical results demonstrate the capability of EMI technique for damage propagation monitoring.

Yang, Yaowen; Liu, Hui; Annamdas, Venu Gopal Madhav

2008-04-01

200

Single ZnO nanowire-PZT optothermal field effect transistors.  

PubMed

A new type of pyroelectric field effect transistor based on a composite consisting of single zinc oxide nanowire and lead zirconate titanate (ZnO NW-PZT) has been developed. Under infrared (IR) laser illumination, the transconductance of the ZnO NW can be modulated by optothermal gating. The drain current can be increased or decreased by IR illumination depending on the polarization orientation of the Pb(Zr(0.3)Ti(0.7))O(3) (PZT) substrate. Furthermore, by combining the photocurrent behavior in the UV range and the optothermal gating effect in the IR range, the wide spectrum of response of current by light offers a variety of opportunities for nanoscale optoelectronic devices. PMID:22895012

Hsieh, Chun-Yi; Lu, Meng-Lin; Chen, Ju-Ying; Chen, Yung-Ting; Chen, Yang-Fang; Shih, Wan Y; Shih, Wei-Heng

2012-08-15

201

Fabrication and characterization of laterally-driven piezoelectric bimorph MEMS actuator with sol–gel-based high-aspect-ratio PZT structure  

NASA Astrophysics Data System (ADS)

This paper reports on the fabrication and characterization of a novel laterally-driven piezoelectric bimorph micro electro mechanical systems actuator with high aspect-ratio (AR) lead–zirconate–titanate (PZT) structures. The PZT structures (AR=8) sandwiched with Pt sidewall electrodes were fabricated by a nanocomposite sol–gel process with micromachined silicon templates. A single-cantilever-type lateral bimorph actuator was successfully fabricated, and no initial vertical bending was observed, even on a 500 µm long actuator. A lateral displacement of 10 µm was obtained in bimorph actuation at driving voltages of +25 V/?5 V. Then the piezoelectric property of the PZT structure was characterized from the actuator's performance. The lateral piezoelectric actuator has a variety of potential applications as a replacement for electrostatic comb drive actuators occupying a large area.

Yoshida, Shinya; Wang, Nan; Kumano, Masafumi; Kawai, Yusuke; Tanaka, Shuji; Esashi, Masayoshi

2013-06-01

202

Mechanism of the phase transformation of the pyrochlore phase into the perovskite phase in lead zirconate titanate films on silicon substrates  

NASA Astrophysics Data System (ADS)

The phase transformation from the pyrochlore phase into the perovskite phase in ferroelectric films of lead zirconate titanate on silicon substrates due to annealing of samples has been investigated experimentally and theoretically. It has been proved that this transformation is a typical first-order phase transition, which is accompanied by a change in the density of the phases and the release of the latent heat of the phase transition. The quantitative evaluations have demonstrated that the difference in the densities of two phases, namely, the perovskite phase and the original parent pyrochlore phase, leads to the generation of elastic stresses in the original parent phase. In turn, these stresses bring about the nucleation of micropores in the bulk of the lead zirconate titanate film. The thermodynamic conditions providing the formation of micropores have been established and the critical size of the micropores has been calculated. A characteristic relationship between the critical size of nuclei of the perovskite phase and the radius of micropores at which the perovskite phase is separated from the parent pyrochlore phase has been derived. This relationship has been verified experimentally. The sizes of the micropores have been determined using scanning electron microscopy, and the changes in the phase composition during the phase transformation have been found using an electron probe X-ray microanalysis. It has been demonstrated theoretically and experimentally that the relaxation of elastic stresses in the lead zirconate titanate thin films during the phase transition occurs through the nucleation and growth of micropores at the interface between the new and parent phases.

Kukushkin, S. A.; Tentilova, I. Yu.; Pronin, I. P.

2012-03-01

203

e31,f determination for PZT films using a conventional `d33' meter  

NASA Astrophysics Data System (ADS)

A new and simple method is described for the determination of the piezoelectric coefficients d33,f and e31,f for piezoelectric films deposited on substrates using a conventional point-loading `d33' or `Berlincourt' piezometer. An analytical mathematical model is developed which simulates the dynamical flexure of such films when a ring-supported sample is subject to central loading. Classical plate theory and elastic analysis are used to calculate the stresses in doped lead zirconate titanate (PZT) film for different radii of supporting rings, enabling both piezoelectric coefficients to be determined through a simple modification to the piezometer. The analytical model for the radial stresses has been evaluated in comparison with the results of finite element analysis and has shown a good correlation. The new measurement technique has been applied to both thick films of PZT and thin films of manganese-doped lead zirconate titanate (PMZT) on silicon substrates. The values of d33,f and e31,f obtained experimentally are found to be similar to those that have been determined by more elaborate methods.

Southin, J. E. A.; Wilson, S. A.; Schmitt, D.; Whatmore, R. W.

2001-05-01

204

Application of PZT sensors for detection of damage severity and location in concrete  

NASA Astrophysics Data System (ADS)

Piezoelectric ceramic lead zirconate titanate (PZT) based electromechanical impedance (EMI) technique has been applied for structural health monitoring (SHM) of various engineering systems. However, study on identification of damage severity and location is still in need. In the EMI method, the PZT electromechanical (EM) admittance is used as a damage indicator. Statistical techniques such as root mean square deviation (RMSD) have been employed to associate the damage level with the changes in the EM admittance signature. To achieve high sensitivity to damage, high frequency signatures (>200 kHz) have been used to monitor the region close to the PZT location. It has been reported that the use of RMSD as the damage indicator is difficult to specify the damage location and severity due to the inconsistency in the RMSD results. This paper proposes the use of large frequency (30-400 kHz) range and the RMSD values of sub-frequency intervals to eliminate the inconsistency in the results. An experiment is carried out on a real size concrete structure subjected to artificial damages. The PZT admittance signatures in a frequency range of 30 to 400 kHz for various structural damages have been recorded and the RMSD values of sub-frequency intervals of 10 kHz are calculated. Results show less inconsistency and uncertainties compared to the traditional method using limited high frequency range. It is observed that the damage close to the PZT changes the RMSD at high frequency range significantly; however the damage far away from the PZT changes the RMSD at low frequency range significantly.

Sabet Divsholi, Bahador; Yang, Yaowen

2008-12-01

205

High-pressure neutron study of the morphotropic lead-zirconate-titanate: Phase transitions in a two-phase system  

NASA Astrophysics Data System (ADS)

The present study was dedicated to the classical piezoelectric, lead-zirconate-titanate ceramic with composition Pb(Zr0.54Ti0.46)O3 at the Zr-rich side of the morphotropic phase boundary at which two phases co-exists. The pressure-induced changes in the phase fractions were studied by high-pressure neutron powder diffraction technique up to 3 GPa and 773 K. The two co-existing phases were rhombohedral R3c and monoclinic Cm at room temperature and R3c and P4mm above 1 GPa and 400 K. The experiments show that pressure favors the R3c phase over the Cm and P4mm phases, whereas at elevated temperatures entropy favours the P4mm phase. At 1 GPa pressure, the transition to the cubic Pm3m phase occurred at around 600 K. Pressure lowers the Cm-->P4mm transition temperature. The Cm phase was found to continuously transform to the P4mm phase with increasing pressure, which is inline with the usual notion that the hydrostatic pressure favours higher symmetry structures. At the same time, the phase fraction of the R3c phase was increasing, implying discontinuous Cm-->R3c phase transition. This is in clear contrast to the polarization rotation model according to which the Cm would link the tetragonal and rhombohedral phases by being a phase in which the polarization would, more or less continuously, rotate from the tetragonal polarization direction to the rhombohedral direction. Pressure induces large changes in phase fractions contributing to the extrinsic piezoelectricity. The changes are not entirely reversible, as was revealed by noting that after high-pressure experiments the amount of rhombohedral phase was larger than initially, suggesting that on the Zr-rich side of the phase boundary the monoclinic phase is metastable. An important contribution to the intrinsic piezoelectricity was revealed: a large displacement of the B cations (Zr and Ti) with respect to the oxygen anions is induced by pressure.

Frantti, J.; Fujioka, Y.; Zhang, J.; Wang, S.; Vogel, S. C.; Nieminen, R. M.; Asiri, A. M.; Zhao, Y.; Obaid, A. Y.; Mkhalid, I. A.

2012-07-01

206

Pressure-induced ferroelectric-antiferroelectric phase transitions in lead zirconate-tatanate-based solid solutions  

NASA Astrophysics Data System (ADS)

The ferroelectric-antiferroelectric phase transitions induced by hydrostatic pressure in solid solutions based on lead zirconate-titanate (PZT) with introducing 20 at % tin into B sites and composites based on these ceramics have been studied. In the composites with the same composition of solid solution, the transition pressure can be varied within wide ranges depending on the type of binders. The latter is due to the vitrification of the binder and, consequently, the formation of a rigid framework preventing the transmission of pressure to the ceramic matrix.

Spiridonov, N. A.; Ishchuk, V. M.; Kisel', N. G.; Spiridonov, V. N.

2012-05-01

207

Effects of quenched impurities and relative antiferroelectric/ferroelectric phase stability on the incommensurately modulated polar structures of La-modified lead zirconate titanate  

SciTech Connect

Structure{endash}property relationship studies have been performed in the La-modified lead zirconate titanate (PLZT) solution as a function of quenched La impurity content and Zr/Ti ratio. For Zr/Ti ratios of 90/10 and 85/15, an incommensurate antiferroelectric state was found to be stabilized with increasing La content. Temperature-dependent investigations demonstrated that the incommensurate structure becomes pinned into long-time metastable states, rather than transforming to a commensurate phase. Also, the modulation wavelength ({lambda}) was found to increase significantly with the decreasing Zr/Ti ratio and decreasing La content. The results of this study clearly demonstrate that the incommensurately modulated polar structures of PLZT are dependent on the relative antiferroelectric/ferroelectric phase stability, and the concentration of quenched La impurities. {copyright} {ital 1997 American Institute of Physics.}

Xu, Z.; Dai, X.H.; Li, J.F.; Viehland, D. [Department of Materials Science and Engineering, and Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)

1997-10-01

208

Effect of dc bias and hydrostatic pressure on the ferroelectric-antiferroelectric phase transformation in a tin modified lead zirconate titanate ceramic.  

SciTech Connect

Phase transformation between the ferroelectric (FE) and the antiferroelectric (AFE) phases in tin modified lead zirconate titanate (PSZT) ceramics can be influenced by pressure and electric field. Increasing the pressure has the tendency to favor the AFE phase while electric field favors the FE phase. In this study, these phase transformations are studied as functions of external pressure, temperature, and dc bias. The shifting of transformation temperature and the relative phase stability between FE and AFE with respect to these external parameters will be presented. Results will be compared to a pressure-induced depoling behavior (or FE-to-AFE phase transformation) for the PSZT ceramic. Fundamental issues relates to the relative phase stability will be discussed from the perspective of lattice dynamics theory.

Grubbs, Robert K.; DiAntonio, Christopher Brian; Yang, Pin; Roesler, Alexander William; Montgomery, Stephen Tedford; Moore, Roger Howard

2010-06-01

209

Electrical properties and electric field-induced antiferroelectric-ferroelectric phase transition in Nd3+-doped lead strontium zirconate titanate ceramics  

NASA Astrophysics Data System (ADS)

Undoped and 1-3 at. % Nd3+-doped lead strontium zirconate titanate ceramics, which were located near the tetragonal antiferroelectric (AFE) and rhombohedral ferroelectric (FE) phase boundary, were prepared by tape casting and sintering. The influence of the electric field-induced AFE to FE phase transition on the piezoelectric and strain behavior was studied. Attempts were made to increase the field-induced strain by Nd3+ doping and its effect on the dielectric properties. Room temperature resistivity was also measured and explained by the defects produced. An in situ x-ray diffraction technique was developed for direct observation of the unit cell dimensions associated with the field-induced AFE to FE phase transition. The results indicated that a change in unit cell volume was responsible for the large field-induced strain associated with the AFE-FE phase transition.

Yu, Yongjian; Singh, Raj N.

2003-12-01

210

Processing of thermally stable doped perovskite PZT ceramics  

Microsoft Academic Search

In this paper, various methods of synthesizing lead zirconium titanate (PZT) ceramics with high Curie temperature (Tc) and thermal stability are discussed. Perovskite PZT variants were synthesized from stoichiometric oxide ratios of Pb, Zr, Ti and dopant element. The oxide powders were mixed mechanically and calcinated, and then sintered for the desired perovskite phase to form. Varied mixing and sintering

G. H. L Wong; B. W Chua; Lu Li; M. O Lai

2001-01-01

211

Fabrication and performance of a single-crystal lead magnesium niobate-lead titanate cylindrical hydrophone.  

PubMed

The development of a piezoelectric hydrophone based on lead magnesium niobate-lead titanate [PbMg1/3Nb2/3O3-PbTiO3 (PMN-PT)] single-crystal piezoelectric as the hydrophone substrate is reported. Although PMN-PT can possess much higher piezoelectric sensitivity than traditional lead zirconate titanate (PZT) piezoelectrics, it is highly anisotropic and therefore there is a large gain in sensitivity only when the crystal structure is oriented in a specific direction. Because of this, simply replacing the PZT substrate with a PMN-PT cylinder is not an optimal solution because the crystal orientation does not uniformly align with the circumferential axis of the hydrophone. Therefore, a composite hydrophone that maintains the optimal crystal axis around the hydrophone circumference has been developed. An 11.3?mm diameter composite hydrophone cylinder was fabricated from a single <110> cut PMN-PT rectangular plate. Solid end caps were applied to the cylinder and the sensitivity was directly compared with a solid PZT-5A cylindrical hydrophone of equal dimensions in a hydrophone test tank. The charge sensitivity showed a 9.1?dB improvement over the PZT hydrophone and the voltage sensitivity showed a 3.5?dB improvement. This was in good agreement with the expected theoretical improvements of 10.1 and 4.5?dB, respectively. PMID:23927102

Brown, Jeremy A; Dunphy, Kevin; Leadbetter, Jeff R; Adamson, Robert B A; Beslin, Olivier

2013-08-01

212

Study on optimizing ultrasonic irradiation period for thick polycrystalline PZT film by hydrothermal method.  

PubMed

The hydrothermal method utilizes a solution-based chemical reaction to synthesize piezoelectric thin films and powders. This method has a number of advantages, such as low-temperature synthesis, and high purity and high quality of the product. In order to promote hydrothermal reactions, we developed an ultrasonic assisted hydrothermal method and confirmed that it produces dense and thick lead-zirconate-titanate (PZT) films. In the hydrothermal method, a crystal growth process follows the nucleation process. In this study, we verified that ultrasonic irradiation is effective for the nucleation process, and there is an optimum irradiation period to obtain thicker PZT films. With this optimization, a 9.2-?m-thick PZT polycrystalline film was obtained in a single deposition process. For this film, ultrasonic irradiation was carried out from the beginning of the reaction for 18 h, followed by a 6 h deposition without ultrasonic irradiation. These results indicate that the ultrasonic irradiation mainly promotes the nucleation process. PMID:23312574

Ohta, Kanako; Isobe, Gaku; Bornmann, Peter; Hemsel, Tobias; Morita, Takeshi

2012-12-23

213

Temperature dependence of a PZT piezoelectric sensor for Mercury Dust Monitor up to 150 °C  

NASA Astrophysics Data System (ADS)

We have been developing a cosmic dust detector for BepiColombo Mercury exploration mission, called Mercury Dust Monitor (MDM). The MDM uses piezoelectric sensors made of lead zirconate titanate (PZT) ceramics for estimation of dust flux and momentum of incident particles. The PZT sensors of MDM, installed on the surface of a side panel of the MMO without a sunshade, will be exposed to severe heat influx from the sun. The sensors are expected to reach their maximum temperature of 167 ° C at perihelion. Since the MDM is not just a dust counter but a particle analyzer, the dependence of the impact signals on temperature is essential to deduce quantitative information on the incident particles from the signals. We have carried out experiments on the temperature dependence of impact signals between room temperature and 150 ° C. A halogen lamp heater is used for heating of a disk PZT sensor in a vacuum chamber at the end of a beam line from the electrostatic accelerator at Max Planck Institute for Nuclear Physics (MPI-K). A linear correlation between the output amplitude voltage of the first oscillation and the momentum of accelerated particles remains even at 150 ° C, and, more importantly, there is no clear difference in the slopes of the linear correlation for room temperature and 150 ° C. This result is quite preferable because it should make the practical data analysis from the MDM easy.

Iwai, Takeo

214

The effects of nonhydrostatic compression and applied electric field on the electromechanical behavior of poled lead zirconate titanate 95\\/5-2Nb ceramic during the ferroelectric to antiferroelectric polymorphic transformation  

Microsoft Academic Search

We conducted hydrostatic compression and constant-stress-difference experiments, with and without an applied electric field, on poled, niobium-doped lead zirconate titanate ceramic. The objective was to quantify the effects of nonhydrostatic stress and electric field bias on electromechanical behavior of the ceramic during the ferroelectric, rhombohedral antiferroelectric, orthorhombic phase transformation. Increasing stress difference (shear stress) decreases the mean stress at which

D. M. Zeuch; D. J. Holcomb

1999-01-01

215

Use of transmission electron microscopy for the characterization of rapid thermally annealed, solution-gel, lead zirconate titanate films  

Microsoft Academic Search

The microstructure and preferred orientations of rapid thermally annealed Pb(Zr[sub 0.5],Ti[sub 0.47])O[sub 3] films, deposited on Pt\\/Ti\\/SiO[sub 2]\\/Si electrode\\/substrates by solution-gel spinning, have been investigated using analytical and high-resolution electron microscopy and X-ray diffraction. The temperature of pyrolysis of the PZT films was found to influence the preferred orientation of the film: lower temperatures (350 C) favored a (111) orientation,

Ian M. Reaney; Keith Brooks; Radosveta Klissurska; Czezlaw Pawlaczyk; Nava Setter

1994-01-01

216

The effects of large AC electric fields on the properties of ferroelectric lead zirconate titanate thin films  

NASA Astrophysics Data System (ADS)

The initial motivation of the research presented here was to understand some novel phenomena reported in compositionally graded ferroelectric films. The phenomenon of primary interest was the translation of ferroelectric hysteresis loops along what is normally regarded as the polarization axis, which was interpreted as a polarization offset with anamolously large and unphysical values. The fabrication of compositionally graded Pb(Zr,Ti)O 3 (PZT) thin films is presented along with the observation of hysteresis loop translations. These hysteresis loop translations were found to be due to a dc voltage offset which develops on the sample capacitor. In addition, these voltage offsets were found to be sensitive to the oxygen partial pressure of the atmosphere in which the films were situated. Similar oxygen dependent voltage offsets were observed for non-graded PZT films. It is proposed that the observed voltage offsets are ultimately the result of a redistribution of oxygen vacancies at the film surface. This hypothesis is supported by the observation of oxygen dependent voltage offsets in yttria stabilized zirconia films. Two models are proposed which attempt to explain how a redistribution of oxygen vacancies might result in the observed voltage offsets. These models are presented along with experimental results which offer insights into their validity. Finally, a course for future studies is recommended.

Brazier, Mark R.

217

Use of transmission electron microscopy for the characterization of rapid thermally annealed, solution-gel, lead zirconate titanate films  

SciTech Connect

The microstructure and preferred orientations of rapid thermally annealed Pb(Zr[sub 0.5],Ti[sub 0.47])O[sub 3] films, deposited on Pt/Ti/SiO[sub 2]/Si electrode/substrates by solution-gel spinning, have been investigated using analytical and high-resolution electron microscopy and X-ray diffraction. The temperature of pyrolysis of the PZT films was found to influence the preferred orientation of the film: lower temperatures (350 C) favored a (111) orientation, whereas higher temperatures (420 C) favored a (100) orientation. Excess Pb was used to control the A-site stoichiometry of the film particularly at the film surface where Pb-deficient crystals could often be observed. The absence of these crystals was shown to be correlated with an improvement in the dielectric response.

Reaney, I.M.; Brooks, K.; Klissurska, R.; Pawlaczyk, C.; Setter, N. (Ecole Polytechnique Federale de Lausanne (Switzerland). Dept. des Materiaux)

1994-05-01

218

PZT-based active damage detection techniques for steel bridge components  

NASA Astrophysics Data System (ADS)

This paper presents the results of experimental studies on piezoelectric lead-zirconate-titanate (PZT)-based active damage detection techniques for nondestructive evaluations (NDE) of steel bridge components. PZT patches offer special features suitable for real-time in situ health monitoring systems for large and complex steel structures, because they are small, light, cheap, and useful as built-in sensor systems. Both impedance and Lamb wave methods are considered for damage detection of lab-size steel bridge members. Several damage-sensitive features are extracted: root mean square deviations (RMSD) in the impedances and wavelet coefficients (WC) of Lamb waves, and the times of flight (TOF) of Lamb waves. Advanced signal processing and pattern recognition techniques such as continuous wavelet transform (CWT) and support vector machine (SVM) are used in the current system. Firstly, PZT patches were used in conjunction with the impedance and Lamb waves to detect the presence and growth of artificial cracks on a 1/8 scale model for a vertical truss member of Seongsu Bridge, Seoul, Korea, which collapsed in 1994. The RMSD in the impedances and WC of Lamb waves were found to be good damage indicators. Secondly, two PZT patches were used to detect damage on a bolt-jointed steel plate, which was simulated by removing bolts. The correlation of the Lamb wave transmission data with the damage classified by in and out of the wave path was investigated by using the TOF and WC obtained from the Lamb wave signals. The SVM was implemented to enhance the damage identification capability of the current system. The results from the experiments showed the validity of the proposed methods.

Park, Seunghee; Yun, Chung-Bang; Roh, Yongrae; Lee, Jong-Jae

2006-08-01

219

Microstructure et propriétés électriques des couches minces de PZT par procédé sol-gel  

NASA Astrophysics Data System (ADS)

Sol-gel method has been used for PZT thin films deposition onto platinized silicon substrates. PZT thin films microstructure depends on the platinum electrode preparation and the thermal treatment duration. PZT is nucleated under a crystalline form generally described as " rosette ". The influence of the platinum electrode morphology on the final grain size and the effect of the titanium as a contact layer between the platinum and the silicon have been investigated. Different thermal treatments have been investigated : the Rapid Thermal Annealing (RTA) method avoids pyrochlore phase formation and leads to small grain sizes. Electrical measurements have been done using top electrodes (platinum) obtained by microlithography. The influence of the parameters described on the hysteresis loop and resistivity is shown. Le dépôt de titano-zirconate de plomb (PZT) par centrifugation sur des substrats de silicium recouverts de platine est réalisé par un procédé du type " sol-gel ". La microstructure des couches obtenues dépend des paramètres suivants : préparation de l'électrode de base et durée du traitement thermique de densification. La nucléation de la phase pérovskite se fait sous la forme de " rosettes ". On décrit l'influence de la couche d'accrochage du platine (sous-couche de titane) et de la morphologie de l'électrode de base sur la taille de grains finale. La méthode du recuit rapide, associée à un prétraitement de l'électrode de base, permet à la fois d'éviter la formation de phase pyrochlore et de former des grains fins et homogènes. Les caractérisations électriques des couches sont faites sous pointes avec des électrodes supérieures réalisées par microlithographie. L'impact des différents paramètres cités plus hauts sur le cycle d'hystérésis est montré.

Faure, S. P.; Hector, J.; Gaucher, P.; Ganne, J. P.

1994-10-01

220

A PZT-based smart aggregate for compressive seismic stress monitoring  

NASA Astrophysics Data System (ADS)

A PZT-based smart aggregate (SA) for compressive seismic stress monitoring is proposed in this paper. The proposed SA consists of a piece of PZT (lead zirconate titanate) patch sandwiched between a pair of marble cubes through epoxy. A soft PZT is selected, rendering the SA as a potential actuator in active sensing. Finite element analysis (FEA) was conducted to investigate the stress distribution in the SA under compression, which is used for calculating its sensitivity to compressive stresses. With a commercially available charge amplifier, the frequency response of both the amplitude and the phase shift of the sensing system are investigated by applying the frequency sweep loading scheme on the proposed SA. The frequency ranges from 0.01 to 10 Hz, corresponding to the range of seismic frequency response of most building structures. The alternating load for evaluating SA sensitivity was applied by the servo-hydraulic machine. The lower limit of frequency response is determined to be 0.5 Hz. The depolarization process of the piezoelectric coefficient of the selected PZT material was investigated to decide the load-holding time in calibration tests. The degradation of the piezoelectric coefficient with a series of compressive pre-stresses from 4.8 to 24 MPa was evaluated, and the experimental results showed that the influence from the considered range of pre-stresses is negligible. Using a commercially available charge amplifier, the proposed SA-based sensing system can monitor the seismic stress of low- and middle-rise building structures under moderate earthquakes.

Hou, S.; Zhang, H. B.; Ou, J. P.

2012-10-01

221

Processing of sol-gel derived PZT coatings on non-planar substrates  

NASA Astrophysics Data System (ADS)

Sol-gel derived lead zirconate titanate (PZT) coatings were prepared on flat substrates and substrates with elevated surface features similar to those found in some microelectromechanical devices. Crystalline PZT coatings with thicknesses ranging from 0.058 to 0960-1317/6/3/001/img1 were fabricated on substrates with features of height 0960-1317/6/3/001/img2 (0960-1317/6/3/001/img3 rise). Coatings were prepared by spin coating alkoxide solution, drying at 0960-1317/6/3/001/img4, and then heating at 0960-1317/6/3/001/img5 and 0960-1317/6/3/001/img6. Thermogravimetric analysis, Fourier transform infrared spectroscopy and x-ray diffraction were used to characterize structural evolution of PZT coatings on flat substrates. For substrates with surface features, the distribution of PZT after spin coating depended on feature height and spinning rate. The thickness of the coating on top of the step was less than that on the surrounding substrate surface; distribution was particularly non-uniform for features with smaller lateral dimensions and for coatings that were thin with respect to the feature height. Coatings on substrates with surface features had a greater tendency to crack and delaminate, particularly after the high temperature (0960-1317/6/3/001/img6) heating. Cracking was more severe when the ratio of coating thickness to step height was low (< 0.35). To best accommodate surface features, multilayer deposition was used to build up the coating thickness prior to the higher temperature processing steps.

Cooney, T. G.; Francis, L. F.

1996-09-01

222

Effects of quenched disorder on La-modified lead zirconate titanate: Long- and short-range ordered structurally incommensurate phases, and glassy polar clusters  

NASA Astrophysics Data System (ADS)

Structure-property relationship studies have been performed in the La-modified lead zirconate titanate (PLZT) solution as a function of quenched La impurity content and Zr/Ti ratio by transmission electron microscopy, lattice imaging, and dielectric spectroscopy. Investigations were performed for 65/35<=Zr/Ti<=90/10. These investigations have demonstrated a general trend in domain structure and polar order with increasing quenched impurity concentration. For Zr/Ti ratios of 90/10 and 85/15, a structurally incommensurate antiferroelectric (AFEin) state was found to be stabilized with increasing La. Temperature dependent investigations demonstrated that the incommensurate structure becomes pinned into long-time metastable states, rather than transforming to a commensurate phase. Also, the modulation wavelength (?) was found to increase significantly with increasing Ti. When ? increased to ~40 Å, polar clusters began to condense from the AFEin order. For Zr/Ti ratios of 80/20 and 65/35, increasing quenched disorder was found to result in the evolution of polar order through a common sequence of domainlike states including polar clusters, tweedlike structures, and normal micron-sized polydomain structures. These results, in conjunction with dielectric spectroscopy, demonstrate a crossover between a long-period incommensurately modulated state and a relaxor ferroelectric state with increasing quenched disorder. Clearly, both quenched disorder (i.e., random fields) and competing polar orderings (i.e., frustration) underlay the unique behaviors of PLZT.

Viehland, Dwight; Dai, X. H.; Li, J. F.; Xu, Z.

1998-07-01

223

Estimation of Resolution and Contact Force of a Longitudinally Vibrating Touch Probe Sensor Using Lead Zirconate Titanate (PZT) Thin-Film Vibrator  

NASA Astrophysics Data System (ADS)

In this paper, the evaluation of the sensitivity, resolution, and contact force of a touch probe sensor device for higher sensitivity and low contact force is reported. Our goal in designing our touch probe sensor was to realize high-resolution, low-contact-force, wide-scanning-area up to mm scale square, and quick-scanning surface profile measurement. The sensitivity and resolution of our touch probe sensor were 2.0× 10-2 mV/nm and 2.4 nm, respectively. Although this resolution depends on the noise level, the noise level of the pre-amplifier circuit was much larger than that of the vibrator. By minimizing the noise of the circuit by using low-noise-type operational amplifiers, higher resolution up to 0.2 nm can be obtained. Although the contact force was estimated to be 25 ?N under a 0.3 Vp-p driving voltage, it will be 300 nN when using a low-noise circuit.

Kanda, Takefumi; Morita, Takeshi; Kurosawa, Minoru K.; Higuchi, Toshiro

2001-05-01

224

Investigations on structural and multiferroic properties of artificially engineered lead zirconate titanate-cobalt iron oxide layered nanostructures  

NASA Astrophysics Data System (ADS)

Mutiferroics are a novel class of next generation multifunctional materials, which display simultaneous magnetic, electric, and ferroelastic ordering, have drawn increasing interest due to their multi-functionality for a variety of device applications. Since, very rare single phase materials exist in nature this kind of properties, an intensive research activity is being pursued towards the development of new engineered materials with strong magneto-electric (ME) coupling. In the present investigation, we have fabricated polycrystalline and highly oriented PbZr0.53,Ti0.47O3--CoFe 2O4 (PZT/CFO) artificially multilayers (MLs) engineered nanostructures thin films which were grown on Pt/TiO2/SiO2/Si and La 0.5Sr0.5CoO3 (LSCO) coated (001) MgO substrates respectively, using the pulsed laser deposition technique. The effect of various PZT/CFO sandwich configurations having 3, 5, and 9 layers, while maintaining similar total PZT and CFO thickness, has been systematically investigated. The first part of this thesis is devoted to the analysis of structural and microstructure properties of the PZT/CFO MLs. X-ray diffraction (XRD) and micro Raman analysis revealed that PZT and CFO were in the perovskite and spinel phases respectively in the all layered nanostructure, without any intermediate phase. The TEM and STEM line scan of the ML thin films showed that the layered structure was maintained with little inter-diffusion near the interfaces at nano-metric scale without any impurity phase, however better interface was observed in highly oriented films. Second part of this dissertation was dedicated to study of the dielectric, impedance, modulus, and conductivity spectroscopies. These measurements were carried out over a wide range of temperatures (100 K to 600 K) and frequencies (100 Hz to 1 MHz) to investigate the grain and grain boundary effects on electrical properties of MLs. The temperature dependent dielectric and loss tangent illustrated step-like behavior and relaxation peaks near the step-up characteristic respectively. The Cole-Cole plots indicate that the most of the dielectric response came from the bulk (grains) MLs below 300 K, whereas grain boundaries and electrode-MLs effects prominent at elevated temperature. The dielectric loss relaxation peaks shifted to higher frequency side with increase in temperature, finally above 300 K, it went out experimental frequency window. Our Cole-Cole fitting of dielectric loss spectra indicated marked deviation from the ideal Debye type of relaxation which is more prominent at elevated temperature. Master modulus spectra support the observation from impedance spectra, it also indicate that the difference between C g and Cgb are higher compared to polycrystalline MLs indicating less effects of grain boundary in highly oriented MLs. We have explained these electrical properties of MLs by Maxwell-Wagner type contributions arising from the interfacial charge at the interface of the MLs structure. Three different types of frequency dependent conduction process were observed at elevated temperature (>300 K), which well fitted with the double power law, sigma(o) = sigma(0) + A 1on1 + A 2on2, it indicates conduction at: Low frequency (<1 kHz) may be due to long range ordering (frequency independent), mid frequency (<10 kHz) may be due to short range hopping, and high frequency (<1 MHz) due to the localized relaxation hopping mechanism. The last part of the thesis is devoted to the study of the multiferroic and magnetoelectric properties of the ML thin films. Both polycrystalline and highly oriented films showed well saturated ferroelectric and ferromagnetic hysteresis loops at room temperature. Temperature dependence of ferroelectric properties showed that polarization slowly decreases from 300 K to 200 K, with complete collapse of polarization at ˜ 100 K, but there was complete recovery of the polarization during heating, which was repeatable over many different experiments. At the same time, in the same temperature interval the remanent magnetization of the MLs showed slo

Ortega Achury, Nora Patricia

225

Processing of PZT Ceramics: Aqueous Mixing Procedures for Powder Consolidation.  

National Technical Information Service (NTIS)

Inhomogeneities in chemical compositions and microstructures can result in lot-to-lot variations in the charge release characteristics of ferroelectric lead-zirconate-titanate ceramics. One source of inhomogeneity is agglomeration and selective sedimentat...

B. C. Bunker D. L. Lamppa R. H. Moore

1986-01-01

226

Influence of composition and pressure on the electric field-induced antiferroelectric to ferroelectric phase transformation in lanthanum modified lead zirconate titanate ceramics.  

PubMed

The electric field-induced phase transformation behavior in lanthanum-doped lead zirconate titanate ceramics was examined by polarization versus electrical field (P-E) measurements carried out from room temperature to 130 degrees C and under hydrostatic pressures from 20 to 300 MPa. The samples with composition (Pb(1-x)La(x))(Zr(0.90)Ti(0.10))(1-x/4)O(3) [PLZT x/90/10; x = 2,3,4 at%] were prepared by the standard solid-state reaction method. The analysis at room temperature under atmospheric pressure showed that the increase in the lanthanum content induces a transformation from the typical ferroelectric hysteresis, observed for PLZT 2,3/90/10, to double-hysteresis loops, typical of antiferroelectric phases, for PLZT 4/90/10 under a strong electric field. Hydrostatic pressure- induced and temperature-induced ferroelectric (FE) to antiferroelectric (AFE) phase transformations were examined. The measured hysteresis loops indicated that the FE-AFE phase transformation depends on both temperature and hydrostatic pressure for PLZT 3/90/10. This composition, which is in a ferroelectric state at room temperature under atmospheric pressure, can be transformed into the antiferroelectric phase by the application of a hydrostatic pressure of 100 MPa or by increasing the temperature to around 90 degrees C. The PLZT 2/90/10 and 4/90/10 compositions displayed predominantly ferroelectric and antiferroelectric behavior, respectively, over the ranges of temperature and hydrostatic pressure examined in the present study. PMID:19811977

Peláiz-Barranco, Aimé; Hall, David A

2009-09-01

227

Optimized pyroelectric properties of 0-3 composites of PZT particles in polyurethane doped with lithium perchlorate.  

PubMed

A substantial improvement in the performance of pyroelectric 0-3 composites of ceramic particles in a polymer matrix has been achieved by doping the polymer matrix material. Readily prepared and polarized films with various volume fractions of lead zirconate-titanate (PZT) particles in polyurethane have been doped in a solution of lithium perchlorate in acetone to increase the conductivity. With an appropriate conductivity, the dielectric permittivities of the ceramic particles and the polymer matrix become matched, resulting in an improvement of the pyroelectric coefficient from about 6 microC/(m(2)K) to about 50 microC/(m(2)K). The experimental results are explained by theoretical predictions. PMID:18276541

Ploss, Bernd; Krause, Markus

2007-12-01

228

Powering low-power implants using PZT transducer discs operated in the radial mode  

NASA Astrophysics Data System (ADS)

This paper reports experimental results that are used to compare operation characteristics of lead zirconate titanate (PZT) piezoelectric ceramic discs operated in the radial mode. The devices are driven to radially vibrate at their lowest fundamental resonant frequency and thus transmit and receive power when immersed in a liquid phantom. A number of 1 mm × 10 mm (thickness × diameter) PZT discs are characterized experimentally within a propagation tank and results discussed. On the basis of these measured characteristics, a novel application is developed and reported for the first time. This consists of a tuned LC resonator circuit which is used at the receiving disc to maximize sensitivity as well as a Seiko start-up IC S-882Z which is employed to charge a capacitor that drives a PIC microcontroller (?C) once the voltage exceeds 2 V DC. We show that a mean input power of 486 mW RMS results in 976 ?W RMS received over a range of 80 mm and that this is sufficient to periodically (every 60 s) power the ?C to directly drive a red LED for 5 ms with a current of 4.8 mA/flash. This approach is suitable for low-power, periodically activated analogue bio-implant applications.

Sanni, Ayodele; Vilches, Antonio

2013-11-01

229

Ion-beam sputtering deposition and magnetoelectric properties of layered heterostructures (FM/PZT/FM)n, where FM - Co or Ni78Fe22  

NASA Astrophysics Data System (ADS)

Magnetoelectric properties of layered heterostructures (FM/PZT/FM)n (n? 3) obtained by ion-beam sputtering deposition of ferromagnetic metal (FM), where FM is the cobalt (Co) or permalloy Ni78Fe22, onto ferroelectric ceramic based on lead zirconate titanate (PZT) have been studied. The polished ferroelectric plates in thickness from 400 to 20 ?m were subjected to finished treatment by ion-beam sputtering. After plasma activation they were covered by the ferromagnetic films from 1 to 6 ?m in thickness. Enhanced characteristics of these structures were reached by means of both the thickness optimization of ferroelectric and ferromagnetic layers and obtaining of ferromagnetic/ferroelectric interfaces being free from defects and foreign impurities. Assuming on the basis of analysis of elastic stresses in the ferromagnetic film that the magnetoelectric effect forms within ferromagnetic/ferroelectric interface, the structures with 2-3 ferromagnetic layers were obtained. In layered heterostructure (Py/PZT/Py)3, the optimal thickness of ferromagnetic film was 2 ?m, and outer and inner ferroelectric layers had 20 ?m and 80 ?m in thickness, respectively. For such structure the maximal magnetoelectric voltage coefficient of 250 mV/(cm Oe) was reached at a frequency 100 Hz in magnetic field of 0.25 T at room temperature. The structures studied can serve as energy-independent elements detecting the change of magnetic or electric fields in electronic devices based on magnetoelectric effect.

Stognij, Alexander; Novitskii, Nikolai; Sazanovich, Andrei; Poddubnaya, Nadezhda; Sharko, Sergei; Mikhailov, Vladimir; Nizhankovski, Viktor; Dyakonov, Vladimir; Szymczak, Henryk

2013-08-01

230

Measurement of effective piezoelectric coefficients of PZT thin films for energy harvesting application with interdigitated electrodes.  

PubMed

Interdigitated electrode (IDE) systems with lead zirconate titanate (PZT) thin films play an increasingly important role for two reasons: first, such a configuration generates higher voltages than parallel plate capacitor-type electrode (PPE) structures, and second, the application of an electric field leads to a compressive stress component in addition to the overall stress state, unlike a PPE structure, which results in tensile stress component. Because ceramics tend to crack at relatively moderate tensile stresses, this means that IDEs have a lower risk of cracking than PPEs. For these reasons, IDE systems are ideal for energy harvesting of vibration energy, and for actuators. Systematic investigations of PZT films with IDE systems have not yet been undertaken. In this work, we present results on the evaluation of the in-plane piezoelectric coefficients with IDE systems. Additionally, we also propose a simple and measurable figure of merit (FOM) to analyze and evaluate the relevant piezoelectric parameter for harvesting efficiency without the need to fabricate the energy harvesting device. Idealized effective coefficients e(IDE) and h(IDE) are derived, showing its composite nature with about one-third contribution of the transverse effect, and about two-thirds contribution of the longitudinal effect in the case of a PZT film deposited on a (100)-oriented silicon wafer with the in-plane electric field along one of the <011> Si directions. Randomly oriented 1-?m-thick PZT 53/47 film deposited by a sol-gel technique, was evaluated and yielded an effective coefficient e(IDE) of 15 C·m(-2). Our FOM is the product between effective e and h coefficient representing twice the electrical energy density stored in the piezoelectric film per unit strain deformation (both for IDE and PPE systems). Assuming homogeneous fields between the fingers, and neglecting the contribution from below the electrode fingers, the FOM for IDE structures with larger electrode gap is derived to be twice as large as for PPE structures, for PZT-5H properties. The experiments yielded an FOM of the IDE structures of 1.25 × 10(10) J/m(3) and 14 mV/? strain. PMID:22899110

Chidambaram, Nachiappan; Mazzalai, Andrea; Muralt, Paul

2012-08-01

231

Impact of thin SrTiO3 seed layer to achieve low-temperature crystallization below 300 °C and ferroelectricity of lead zirconate titanate thin film  

NASA Astrophysics Data System (ADS)

The authors report low-temperature preparation of Pb(Zr0.6,Ti0.4)O3 (PZT) thin films below 300 °C using SrTiO3 seed layers on (111)Pt/IrO2/SiO2/(001)Si substrates by metal-organic chemical vapor deposition. The critical parameters contributing low-temperature preparation for PZT were crystallinity and orientation of SrTiO3 seeds and deposition rate of PZT films. Using 1-2 nm of SrTiO3 with (h00) and (hh0) mixed orientations, polycrystalline PZT films could be obtained at 290 °C with deposition rate of 0.5-1.0 nm/min. The remanent polarization (2Pr) and coercive field (2Ec) of PZT films on SrTiO3 seeds with deposition rate of 0.5 nm/min were 42.4 ?C/cm2 and 256 kV/cm, respectively.

Moon, Ji-Won; Tazawa, Shogo; Shinozaki, Kazuo; Wakiya, Naoki; Mizutani, Nobuyasu

2006-11-01

232

Effects of electric field on the fracture toughness (KIc) of ceramic PZT  

NASA Astrophysics Data System (ADS)

This work was motivated by the observation that a small percentage of the ceramic lead zirconate titanate (PZT) parts in a device application, one that requires an electrode pattern on the PZT surface, developed fatigue cracks at the edges of the electrodes; yet all of the parts were subjected to similar loading. To obtain additional information on the fracture behavior of this material, similar specimens were run at higher voltage in the laboratory under a microscope to observe the initiation and growth of the fatigue cracks. A sequence of experiments was next performed to determine whether there were fracture toughness variations that depended on material processing. Plates were cut from a single bar in different locations and the Vickers indentation technique was used to measure the relative fracture toughness as a function of position along the bar. Small variations in toughness were found, that may account for some of the devices developing fatigue cracks and not others. Fracture toughness was measured next as a function of electric field. The surface crack in flexure technique was modified to apply an electric field perpendicular to a crack. The results indicate that the fracture toughness drops under a positive electric field and increases under a negative electric field that is less than the coercive field, but as the negative coercive field is approached the fracture toughness drops. Examination of the fracture surfaces using an optical microscope and a surface profilometer reveal the initial indentation crack shape and (although less accurately) the crack shape and size at the transition from stable to unstable growth. These results are discussed in terms of a ferroelastic toughening mechanism that is dependent on electric field.

Goljahi, Sam; Lynch, Christopher S.

2013-09-01

233

Compensator design for hysteresis of a stacked PZT actuator using a congruency-based hysteresis model  

NASA Astrophysics Data System (ADS)

This paper proposes a rate-independent hysteresis compensator for a stacked PZT (lead zirconate titanate) actuator. From a congruency-based hysteresis (CBH) model which is derived from the inherent properties of this actuator, especially the congruency, a feedforward compensator associated with it is developed. The formulation of the proposed compensator is based on an assumption that the inverse operator also possesses the same properties as the CBH model does. This implies that the compensator also possesses properties such as the wiped-out loop closing between the consecutive control points and congruency. Consequently, the expressions for the compensator can be conducted by exploiting the equations for the CBH model in two cases of monotonic increase and monotonic decrease of input excitation. In order to assess the performance of the compensator, several experiments in both open-loop and closed-loop controls are undertaken. In the open-loop control experiment, the performance of the feedforward compensator using the CBH model is compared with the classical Preisach model-based one in three cases of reference waveforms. In the closed-loop control experiment, the proposed compensator is incorporated into a PID (proportional-integral-derivative) control system and the performance of this integrated system is then evaluated and compared to that of the PID with and without compensator.

Nguyen, Phuong-Bac; Choi, Seung-Bok

2012-01-01

234

Low-Temperature Processing of PZT Thick Film by Seeding and High-Energy Ball Milling and Studies on Electrical Properties  

NASA Astrophysics Data System (ADS)

Lead zirconate titanate thick film with molecular formula PbZr0.52Ti0.42O3 (PZT) was prepared by a modified conventional sol-gel method through seeding and high-energy ball milling, resulting in perovskite phase formation at lower temperatures. The ball-milling time was optimized by keeping the seed particle loading (5 wt.%) constant in the sol-gel solution. This methodology helped in reduction of the crystalline phase formation temperature to 300°C, which is much lower than that reported in the literature (450°C). The well-established perovskite phase was confirmed by x-ray diffraction (XRD) analysis. Scanning electron microscopy (SEM) of PZT films revealed uniform and crystalline microstructure. Film prepared by this methodology showed higher spontaneous polarization (2.22 ?C/cm2), higher capacitance (1.17 nF), and low leakage current density (18 ?A/cm2). The results obtained from ferroelectric characterization showed a strong correlation with the XRD and SEM results.

Dutta, Soma; Jeyaseelan, A. Antony; Sruthi, S.

2013-09-01

235

A constitutive model for ferroelectric PZT ceramics under uniaxial loading  

Microsoft Academic Search

Our aim is the presentation of a macroscopic constitutive model for the purpose of engineering reliability analysis of piezoceramic components designed for so-called 'smart' electromechanical sensor and actuator applications. Typically, such components are made of materials like ferroelectric lead zirconate titanate ceramics which exhibit significant history-dependent nonlinearities such as the well known dielectric, butterfly and ferroelastic hystereses due to switching

Marc Kamlah; Qing Jiang

1999-01-01

236

The effects of nonhydrostatic compression and applied electric field on the electromechanical behavior of poled lead zirconate titanate 95/5-2Nb ceramic during the ferroelectric to antiferroelectric polymorphic transformation  

SciTech Connect

We conducted hydrostatic compression and constant-stress-difference experiments, with and without an applied electric field, on poled, niobium-doped lead zirconate titanate ceramic. The objective was to quantify the effects of nonhydrostatic stress and electric field bias on electromechanical behavior of the ceramic during the ferroelectric, rhombohedral {r_arrow} antiferroelectric, orthorhombic phase transformation. Increasing stress difference (shear stress) decreases the mean stress at which the transformation occurs. Increasing shear stress also retards the rate of transformation, causing reductions in both the rate of charge release and peak voltage attained during depoling. Application of the electric field bias slightly increases the transformation pressure for poled ceramic. Previously, we showed that under nonhydrostatic stress, the transformation took place in {ital unpoled} ceramic when the maximum compressive stress equalled the hydrostatic pressure at which the transformation would otherwise occur. This simple stress criterion does not apply to poled ceramic. However, poled material has a preferred crystallographic orientation and mechanical anisotropy, whereas unpoled ceramic is isotropic. We present a qualitative model for the transformation under nonhydrostatic stress-related to that anisotropy, which resolves these seemingly disparate observations. {copyright} {ital 1999 Materials Research Society.}

Zeuch, D.M.; Holcomb, D.J. [Geomechanics Department 6117, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)] Montgomery, S.T. [Integrated Product Development Department 1567, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)

1999-05-01

237

Sol-gel synthesis of high-quality SrRuO{sub 3} thin film electrodes suppressing the formation of detrimental RuO{sub 2} and the dielectric properties of integrated lead lanthanum zirconate titanate films.  

SciTech Connect

A facile solution chemistry is demonstrated to fabricate high-quality polycrystalline strontium ruthenium oxide (SrRuO{sub 3}) thin film electrodes on silicon substrates suppressing the formation of undesired ruthenium oxide (RuO{sub 2}) for the deposition of dielectric and ferroelectric materials like lead lanthanum zirconate titanate (PLZT). The robust, highly crystalline SrRuO{sub 3} film fabrication process does not favor the formation of RuO{sub 2} because of molecular level modification of the precursors possessing analogous melting points, yielding homogeneous films. This chemistry is further understood and complemented by kinetic and thermodynamic analysis of the DTA data under nonisothermal conditions, with which the activation energies to form RuO{sub 2} and SrRuO{sub 3} were calculated to be 156 {+-} 17 and 96 {+-} 10 kJ/mol, respectively. The room-temperature resistivity of the SrRuO{sub 3} film was measured to be 850 {+-} 50 {mu}{Omega} cm on silicon (100) substrates. The dielectric properties of sol-gel-derived PLZT thin film capacitors on polycrystalline SrRuO{sub 3} electrodes were also measured to illustrate the high quality of the formed SrRuO{sub 3} bottom electrode. These results have broad implications for the expanded use of these conductive oxide electrodes in many applications that require low thermal budgets. The PLZT (8/52/48) films exhibited well-defined hysteresis loops with remanent polarization of {approx}10.5 {micro}C/cm{sup 2}, dielectric constant of >1450, dielectric loss of <0.06, and leakage current density of {approx}3.8 x 10{sup -8} A/cm{sup 2}. These dielectric properties are similar to those of PLZT on platinized silicon, indicating the high quality of the bottom conductive oxide layer. In addition, the PLZT capacitors were essentially fatigue free for >1 x 10{sup 9} cycles when deposited over an oxide electrode.

Narayanan, M.; Tong, S.; Koritala, R.; Ma, B.; Pol, V.; Balachandran, U.

2011-01-01

238

RMS Titanic  

NSDL National Science Digital Library

RMS Titanic raised a 23- by 14-foot section of the Titanic's outer hull this week. RMS, which has exclusive rights to photograph the Titanic and to possess any items recovered from the wreck, doesn't miss an opportunity to market Titanic-oriented merchandise on their site. Nonetheless, visitors wanting to know more about the Titanic will be interested in the expedition calendar and background information on the Titanic's voyage and the exploration of its remains.

2000-01-01

239

Stereolithography of PZT ceramic suspensions  

Microsoft Academic Search

The characteristics of PZT suspensions have been studied and fit to stereolithography restraints. On one hand, researches concern the influence of fillers contents, dispersant concentration, temperature and resins nature and amount on suspensions rheological behaviour. On the other hand, the influence of photoinitiator and PZT concentrations, density of energy and nature of the resin on suspension reactivity was investigated. These

O. Dufaud; S. Corbel

2002-01-01

240

An ultrasonic micromotor using a bending cylindrical transducer based on PZT thin film  

Microsoft Academic Search

Ultrasonic motors have a good high-torque performance. In particular, it seems that cylinder-type ultrasonic motors are superior to disk- or ring-type ones in the sense of high-torque application. For miniaturization of the motor size, a simple structure of an ultrasonic transducer becomes effective. This paper presents an ultrasonic micromotor using a bending cylindrical transducer based on a lead zirconate titanate

Takeshi Morita; Minoru Kurosawa; Toshiro Higuchi

1995-01-01

241

Pb diffusion in zircon  

Microsoft Academic Search

Diffusion of Pb was characterized in natural and synthetic zircon under a range of conditions. In most experiments, mixtures of Pb sulfate and ground zircon were used as the sources of diffusant, with Pb depth profiles measured with Rutherford Backscattering Spectrometry (RBS). As complement to these “in-diffusion” experiments, “out-diffusion” experiments were run on both synthetic Pb-doped and natural zircon with

D. J Cherniak; E. B Watson

2001-01-01

242

Interfacial Delamination of PZT Thin Films  

Microsoft Academic Search

\\u000a The interface strength of Pb(Zr,Ti)O3(PZT) thin films on a silicon substrate is studied experimentally and numerically in this work. First, a sandwiched cantilever\\u000a specimen is proposed to perform the delamination tests. The experimental results show that the multilayered Cr\\/PZT\\/PLT\\/Pt\\/Ti\\u000a thin films deposited on single-crystal silicon substrates are delaminated along the interface between Cr and PZT layers in\\u000a a brittle manner.

Fulin Shang; Yabin Yan; Takayuki Kitamura

243

Molecular Structure of Zircon  

NSDL National Science Digital Library

Zircon (zirconium silicate) was found in Greece and Italy as far back as the 6th Century A.D. Zircon comes from the Persian word "zargun" which means gold-colored. Zircon has been used as a diamond substitute because it resembles diamond in luster and has been mistaken for diamonds by many experienced jewelers, although it is not the same as Cubic Zirconia. It can be brown, red, green, blue, yellow, black, violet, orange and colorless. A typical crystal of zircon is shaped like a tetragonal prism with four sided prisms at each end. Zircon can be found in Laacher Sea, Niedermendig and Germany, and is mined in Cambodia, Sri Lanka, Thailand, Myanmar, Australia, and other countries.

2002-09-06

244

Radiation Effects in Zircon  

SciTech Connect

The widespread distribution of zircon in the continental crust, its tendency to concentrate trace elements, particularly lanthanides and actinides, its use in age-dating, and its resistance to chemical and physical degradation have made zircon the most important accessory mineral in geologic studies. Because zircon is highly refractory, it also has important industrial applications, including its use as a lining material in high-temperature furnaces. However, during the past decade, zircon has also been proposed for advanced technology applications, such as a durable material for the immobilization of plutonium or, when modified by ion-beam irradiation, as an optic waveguide material. In all of these applications, the change in properties as a function of increasing radiation dose is of critical importance. In this chapter, we summarize the state-of-knowledge on the radiation damage accumulation process in zircon.

Ewing, Rodney C.; Meldrum, Alkiviathes; Wang, L. M.; Weber, William J.; Corrales, Louis R.

2003-12-11

245

Zircons are Forever  

NSDL National Science Digital Library

Zircons have been in the news lately because of the recent discovery that the chemical signature of the oldest known zircon crystal (4.4 billion years) suggests that water, and thus conditions for life on Earth, was present then. Geologists at the University of Wisconsin-Madison contributed to a large part of this study. Zircons are Forever is a newly posted feature page on the UW Geology and Geophysics Website. The text describes the basic chemistry of zircon and why it is an important mineral for studies of mantle formation. Particular emphasis is on stable isotope geochemistry. A hyperlinked bibliography leads to abstracts and plots of oxygen isotope values from papers by UW faculty and graduate students. Zircons are Forever adds a little more background to the recent headlines.

246

The Titanic  

NSDL National Science Digital Library

You will be exploring the R.M.S Titanic. This includes an individual passenger, the class system on board, the collision and warnings leading up to it, and the construction of the ship. Introduction: You are going to be a passenger on board the RMS Titanic. You boarded the ship and set sail expecting the experience of a lifetime upon the Ship of Dreams, but what will happen next? In this project we will be exploring how the ship was structured, what activities were ...

Van Vooren, Ms.

2007-12-04

247

RMS TITANIC  

NSDL National Science Digital Library

You will be exploring the R.M.S Titanic. This includes an individual passenger, the class system on board, the collision and warnings leading up to it, and the construction of the ship. Introduction: You are going to be a passenger on board the RMS Titanic. You boarded the ship and set sail expecting the experience of a lifetime upon the Ship of Dreams, but what will happen next? In this project we will be exploring how the ship was structured, what activities were ...

Klooney

2010-04-20

248

RMS Titanic  

NSDL National Science Digital Library

You will be exploring the R.M.S Titanic. This includes an individual passenger, the class system on board, the collision and warnings leading up to it, and the construction of the ship. Introduction: You are going to be a passenger on board the RMS Titanic. You boarded the ship and set sail expecting the experience of a lifetime upon the Ship of Dreams, but what will happen next? In this project we will be exploring how the ship was structured, what activities were ...

Mr.taylor

2010-04-20

249

RMS TITANIC  

NSDL National Science Digital Library

You will be exploring the R.M.S Titanic. This includes an individual passenger, the class system on board, the collision and warnings leading up to it, and the construction of the ship. Hi Hillside Third Graders! Welcome to the Titanic... To watch some videos of the Wreck click on this link below. Scroll down and click on the yellow link above the YouTube screen that says watch more videos. Use the left side of the screen to help you find the word "Wreck Videos". Watch three ...

Law, Miss

2010-04-20

250

Li diffusion in zircon  

NASA Astrophysics Data System (ADS)

Diffusion of Li under anhydrous conditions at 1 atm and under fluid-present elevated pressure (1.0-1.2 GPa) conditions has been measured in natural zircon. The source of diffusant for 1-atm experiments was ground natural spodumene, which was sealed under vacuum in silica glass capsules with polished slabs of zircon. An experiment using a Dy-bearing source was also conducted to evaluate possible rate-limiting effects on Li diffusion of slow-diffusing REE+3 that might provide charge balance. Diffusion experiments performed in the presence of H2O-CO2 fluid were run in a piston-cylinder apparatus, using a source consisting of a powdered mixture of spodumene, quartz and zircon with oxalic acid added to produce H2O-CO2 fluid. Nuclear reaction analysis (NRA) with the resonant nuclear reaction 7Li(p,?)8Be was used to measure diffusion profiles for the experiments. The following Arrhenius parameters were obtained for Li diffusion normal to the c-axis over the temperature range 703-1.151°C at 1 atm for experiments run with the spodumene source: D_{text{Li}} = 7.17 × 10^{ - 7} { exp }( - 275 ± 11 {text{kJmol}}^{ - 1} /{text{RT}}){text{m}}2 {text{s}}^{ - 1}. Diffusivities are similar for transport parallel to the c-axis, indicating little anisotropy for Li diffusion in zircon. Similar Li diffusivities were also found for experiments run under fluid-present conditions and for the experiment run with the Dy-bearing source. Li diffusion is considerably faster than diffusion of other cations in zircon, with a smaller activation energy for diffusion. Although Li diffusion in zircon is comparatively rapid, zircons will be moderately retentive of Li signatures at mid-crustal metamorphic temperatures, but they are unlikely to retain this information for geologically significant times under high-grade metamorphism.

Cherniak, D. J.; Watson, E. B.

2010-09-01

251

Zircon Recycling in Arc Intrusions  

Microsoft Academic Search

Recycling of zircon has been well established in arc intrusions and arc volcanoes, but a better understanding of where and how zircons are recycled can help illuminate how arc magma systems are constructed. To that end, we are conducting age, trace element (including Ti-in-zircon temperatures; TzrnTi) and isotopic studies of zircons from the Late Cretaceous (95-85 Ma) Tuolumne Intrusive Suite

J. Miller; A. Barth; J. Matzel; J. Wooden; S. Burgess

2008-01-01

252

Future Titan Missions  

NASA Astrophysics Data System (ADS)

New discoveries about Titan from the Cassini-Huygens mission have led to a broad range of mission class studies for future missions, ranging from NASA Discovery class to International Flagship class. Three consistent science themes emerge and serve as a framework for discussing the various mission concepts: Goal A: Explore Titan, an Earth-Like System - How does Titan function as a system? How are the similarities and differences with Earth, and other solar system bodies, a result of the interplay of the geology, hydrology, meteorology, and aeronomy present in the Titan system?; Goal B: Examine Titan’s Organic Inventory—A Path to Prebiological Molecules - What is the complexity of Titan’s organic chemistry in the atmosphere, within its lakes, on its surface, and in its putative subsurface water ocean and how does this inventory differ from known abiotic organic material in meteorites and therefore contribute to our understanding of the origin of life in the Solar System?; and Goal C: Explore Enceladus and Saturn’s magnetosphere—clues to Titan’s origin and evolution - What is the exchange of energy and material with the Saturn magnetosphere and solar wind? What is the source of geysers on Enceladus? Does complex chemistry occur in the geyser source? Within this scientific framework the presentation will overview the Titan Explorer, Titan AND Enceladus Mission, Titan Saturn System Mission, Titan Mare Explorer, and Titan Submersible. Future timelines and plans will be discussed.

Waite, J. H.; Coustenis, A.; Lorenz, R.; Lunine, J.; Stofan, E.

2012-04-01

253

Li diffusion in zircon  

Microsoft Academic Search

Diffusion of Li under anhydrous conditions at 1 atm and under fluid-present elevated pressure (1.0–1.2 GPa) conditions has\\u000a been measured in natural zircon. The source of diffusant for 1-atm experiments was ground natural spodumene, which was sealed\\u000a under vacuum in silica glass capsules with polished slabs of zircon. An experiment using a Dy-bearing source was also conducted\\u000a to evaluate possible rate-limiting effects

D. J. CherniakE; E. B. Watson

2010-01-01

254

Screen printed PZT\\/PZT thick film bimorph MEMS cantilever device for vibration energy harvesting  

Microsoft Academic Search

We present a MEMS-based PZT\\/PZT thick film bimorph vibration energy harvester with an integrated silicon proof mass. The most common piezoelectric energy harvesting devices utilize a cantilever beam of a non piezoelectric material as support beneath or in-between the piezoelectric material. It provides mechanical support but it also reduces the power output. Our device replaces the support with another layer

R. Xu; A. Lei; T. L. Christiansen; K. Hansen; M. Guizzetti; K. Birkelund; E. V. Thomsen; O. Hansen

2011-01-01

255

Anomalous losses of lead in crystallization of the perovskite phase in thin PZT films  

NASA Astrophysics Data System (ADS)

A study has been performed of the mechanisms underlying evolvement of excess lead oxide from lead zirconate titanate films grown ex-situ in two different regimes by magnetron sputtering. In the first case, crystallization of the dense phase of perovskite passed through an intermediate "porous" phase, and in the second, straight through. It has been found that the anomalously large losses of lead are caused by migration of lead over interphase porous boundaries to the surface of the films and depend strongly on the regime of film preparation. The unusual variation of film composition with increasing annealing temperature has been discussed.

Pronin, V. P.; Senkevich, S. V.; Kaptelov, E. Yu.; Pronin, I. P.

2013-01-01

256

Virtual Titanic  

NSDL National Science Digital Library

The recent historical and cinematic fascination with the Titanic proves that the allure of this most famous luxury liner remains unsinkable. The Discovery Channel Online has created a captivating site devoted to images, movies (IPIX, QuickTime), and text describing the ship and its demise. While the site contains historical photos and lithographs of the ship as well as underwater photos and movies from a 1985 submersible mission, the unique contribution of this site is its numerous virtual images of the interior and exterior of the Titanic as well as its movies of the collision and sinking. Developed by Andrew Nelson for a CD-ROM game, the movies include a flyby of the ship, a collision movie, a listing movie, and a three-part series of the sinking. Both flat and "bubble" views of such features as the first-class cabins, the wireless room, and the grand staircase are also included. A talk-back section discusses various theories surrounding the sinking and contains several related links.

1997-01-01

257

Fabrication and characterization of MEMS-based PZT/PZT bimorph thick film vibration energy harvesters  

NASA Astrophysics Data System (ADS)

We describe the fabrication and characterization of a significantly improved version of a microelectromechanical system-based PZT/PZT thick film bimorph vibration energy harvester with an integrated silicon proof mass; the harvester is fabricated in a fully monolithic process. The main advantage of bimorph vibration energy harvesters is that strain energy is not lost in mechanical support materials since only Pb(ZrxTi1-x)O3 (PZT) is strained; as a result, the effective system coupling coefficient is increased, and thus a potential for significantly higher output power is released. In addition, when the two layers are connected in series, the output voltage is increased, and as a result the relative power loss in the necessary rectifying circuit is reduced. We describe an improved process scheme for the energy harvester, which resulted in a robust fabrication process with a record high fabrication yield of 98%. The robust fabrication process allowed a high pressure treatment of the screen printed PZT thick films prior to sintering. The high pressure treatment improved the PZT thick film performance and increased the harvester power output to 37.1 ?W at 1 g root mean square acceleration. We also characterize the harvester performance when only one of the PZT layers is used while the other is left open or short circuit.

Xu, R.; Lei, A.; Dahl-Petersen, C.; Hansen, K.; Guizzetti, M.; Birkelund, K.; Thomsen, E. V.; Hansen, O.

2012-09-01

258

Reactive PZT precursor powder by coprecipitation  

Microsoft Academic Search

Lead, zirconium and titanium were coprecipitated from their aqueous salt solutions using oxalic acid. The precipitate on heating to 850 °C gave phase pure PZT powder which showed good sinterability. The average grain size in the pellets sintered at 900 °C for 6 h was about 1 ?m. Barium and strontium were found to coprecipitate with lead facilitating partial substitution.

K. Rama Mohana Rao; A. V. Prasada Rao; S. Komarneni

1996-01-01

259

Modeling, Optimization, and Design of Efficient Initially Curved Piezoceramic Unimorphs for Energy Harvesting Applications  

Microsoft Academic Search

The piezoceramic, lead zirconate titanate (PZT), is capable of producing large voltages with relatively minimal currents in response to an applied mechanical load when employed in initially curved laminates. This study addresses the issue of optimizing design parameters of a curved PZT unimorph to maximize charge generation due to mechanical loading. A horizontally placed PZT unimorph structure generates surface charge

Hwan-Sik Yoon; Gregory Washington; Amita Danak

2005-01-01

260

Research on Zircon Polarizers.  

National Technical Information Service (NTIS)

Experiments on the growth of single crystal zircon (ZrSiO4) were continued with the hydrothermal method. High quality growth at 0.003 inch per day continued to be obtained in 1.0 inch internal diameter autoclaves when used near 600C with a mixed minearali...

R. Uhrin R. F. Belt R. C. Puttbach

1972-01-01

261

Research on Zircon Polarizers.  

National Technical Information Service (NTIS)

Experiments on the growth of single crystal zircon (ZrSiO4) were continued with the hydrothermal method. Autoclaves of 1.0-1.5 inch diameter have produced growth rates of 0.009 inch per day on (100) plane seeds with a mixed mineralizer consisting of 5mKF-...

R. Uhrin R. F. Belt R. C. Puttbach

1972-01-01

262

Research on Zircon Polarizers.  

National Technical Information Service (NTIS)

Attempts to grow single crystals of zircon (ZrSiO4) by molten salt and hydrothermal techniques are described. Crystals up to 8mm in size were grown from a lithium tungstate melt. The major problems experienced with the use of the tungstate flux have been ...

R. F. Belt R. C. Puttbach R. Dharmarajan

1971-01-01

263

Titan 2D: Understanding Titan’s Seasonal Atmospheric Cycles  

NASA Astrophysics Data System (ADS)

In this study, we present results from a novel two-dimensional (2D) model that simulates the physics and chemistry of Titan’s atmosphere. Despite being an icy moon of Saturn, Titan is the only Solar System object aside from Earth that is sheathed by a thick nitrogen-dominated atmosphere. This vulnerable gaseous envelope—an embodiment of a delicate coupling between photochemistry, radiation, and dynamics—is Nature’s laboratory for the synthesis of complex organic molecules. Titan’s large obliquity generates pronounced seasonal cycles in its atmosphere, and the Cassini spacecraft has been observing these variations since 2004. In particular, Cassini measurements show that the latitudinal distribution of Titan’s rich mélange of hydrocarbon species follows seasonal patterns. The mixing ratios of hydrocarbons increase with latitude towards the winter pole, suggesting a pole-to-pole circulation that reverses after equinox. Using a one-dimensional photochemical model of Titan’s atmosphere, we show that photochemistry alone cannot produce the observed meridional hydrocarbon distribution. This necessitates the employment of a 2D chemistry-transport model that includes meridional circulation as well as diffusive processes and photochemistry. Of additional concern, no previous 2D model of Titan extends beyond 500 km altitude—a critical limitation since the peak of methane photolysis is at 800 km. Our 2D model is the first to include Titan’s stratosphere, mesosphere, and thermosphere. The meridional circulation in our 2D model is derived from the outputs of two general circulation models (GCMs): the TitanWRF GCM (Newman et al. 2011) covering the troposphere, stratosphere, and lower mesosphere, and a thermosphere general circulation model (TGCM) covering the remainder of the atmosphere through the thermosphere (Müller-Wodarg et al. 2003; 2008). This presentation will focus on the utilization of these advances applied to the 2D Caltech/JPL KINETICS model to understand the seasonal and meridional distribution of hydrocarbons as well as other atmospheric cycles on Titan.

Wong, Michael; Zhang, X.; Li, C.; Hu, R.; Shia, R.; Newman, C.; Müller-Wodarg, I.; Yung, Y.

2013-10-01

264

Electrolytic deposition of PZT on carbon fibers for fabricating multifunctional composites  

NASA Astrophysics Data System (ADS)

Piezoelectric fiber composites (PFCs) have been developed in order to overcome the fragile nature of monolithic piezoelectric materials by embedding piezoceramic inclusions into a polymer matrix. The flexible nature of the polymer matrix protects the piezoelectric fiber from damage or fracture under mechanical loading and allows the composites to be easily conformed to curved surfaces for use in many applications. Although PFCs have many useful properties, they still suffer from several drawbacks, namely the required separate electrodes make it impossible to embed the composites into the host structure, and the relatively low tensile modulus of the piezoelectric inclusion means that it contributes little to structural properties. To resolve the inadequacies of current PFCs, a novel active structural fiber (ASF) was developed that can be embedded into a composite structure to perform sensing and actuation, and provide load bearing functionality. The concept and feasibility of this ASF has been validated by coating a silicon carbide (SiC) fiber with a barium titanate (BaTiO3) shell using electrophoresis deposition techniques. However, lead based ceramics react with SiC fiber during high temperature sintering and thus the use of these highly coupled piezoceramics requires alternative deposition approaches. This paper will introduce a new ASF fabricated by coating a single carbon fiber with a concentric PZT (PbZr0.52Ti0.48O3) shell using electrolytic deposition (ELD). ELD quickly and uniformly coats the fiber and, since the PZT precursor has a low crystallization temperature, the carbon fiber is not exposed to high sintering temperatures which typically degrade the in-plane material properties of the fiber and composite. Carbon fiber has been widely used in industry and studied in academia due to its excellent mechanical properties, while PZT has been extensively used for sensing or actuation because of its high piezoelectric coupling. Crystal structures of the PZT before and after annealing are characterized by means of x-ray diffraction, and a pure perovskite structure of the PZT after annealing is shown.

Lin, Y.; Shaffer, J. W.; Sodano, H. A.

2010-12-01

265

Titanic: A Statistical Exploration.  

ERIC Educational Resources Information Center

|Uses the available data about the Titanic's passengers to interest students in exploring categorical data and the chi-square distribution. Describes activities incorporated into a statistics class and gives additional resources for collecting information about the Titanic. (ASK)|

Takis, Sandra L.

1999-01-01

266

Titan's Exotic Weather  

Microsoft Academic Search

Images of Titan, taken during the joint NASA and European Space Agency Cassini-Huygens mission, invoke a feeling of familiarity: washes wind downhill to damp lakebeds; massive cumuli form and quickly dissipate, suggestive of rain; and dark oval regions resemble lakes. These features arise from Titan's unique similarity with Earth: both cycle liquid between their surfaces and atmospheres, but in Titan's

Caitlin A. Griffith

2006-01-01

267

An Infrared Study of PZT Nanoislands  

Microsoft Academic Search

PZT (40\\/60) nanoislands were prepared on (001) MgO substrates by chemical solution deposition. This method allows to prepare uniform and good-quality structures and to tune their size. The structures were characterized by electron microscopy and AFM. It was found that the islands were about 20 nm high and their lateral size was about 100 nm. We measured the infrared reflectance

V. Železný; I. Szafraniak; M. Alexe; D. Hesse

2008-01-01

268

Multilayer piezoelectric devices based on PZT  

Microsoft Academic Search

A PZT 53\\/47 was obtained by a modified chemical route. Small-particle-size powders were allowed to obtain high solid content, non-aqueous slips with Newtonian behaviour. The use of both the tape-casting technique and the common multilayer ceramic fabrication process led to a high-density multilayer ceramic body without cracks or delaminations, and a homogeneous microstructure. The architecture of multilayer piezoelectrics has an

E. Nieto; J. F. Fernandez; C. Moure; P. Duran

1996-01-01

269

Zircon and granite petrology  

Microsoft Academic Search

The typologic study of zircon populations from granitic rocks lead to the proposition of a genetic classification with three main divisions: (1) granites of crustal or mainly crustal origin [(sub) autochthonous and aluminous granites)]; (2) granites of crustal+mantle origin, hybrid granites (calc-alkaline and sub-alkaline series granites); (3) granites of mantle or mainly mantle origin (alkaline and tholeiitic series granites). In

J. P. Pupin

1980-01-01

270

Fabrication of single crystal PZT thin films on glass substrates  

Microsoft Academic Search

We have successfully transferred heteroepitaxial Pb(Zr,Ti)O3 (PZT) thin films from MgO substrates on to glass substrates. The transferred PZT thin films exhibit single crystal structure with ferroelectric properties similar to the as-grown epitaxial films. The transferring process comprises coating of Cr-metallized surface of epitaxial PZT thin films, pressing and cementing the Cr-metallized surface on to the glass substrates by silicone

Kenichiro Terada; Takaaki Suzuki; Isaku Kanno; Hidetoshi Kotera

2007-01-01

271

Microstructural studies of PZT thick films on Cu foils  

Microsoft Academic Search

This paper explains the limits of processing conditions for Pb(Zr,Ti)O3 (PZT) thick films on Cu substrates. PZT thick films in the thickness range 5–20?m deposited on flexible Cu foils by electrophoretic deposition showed poorer properties when compared with PZT thick films deposited on Pt foils under identical conditions. Although the density of the sintered films and the electrical properties were

Aiying Wu; P. M. Vilarinho; S. Srinivasan; A. I. Kingon; I. M. Reaney; D. Woodward; A. R. Ramos; E. Alves

2006-01-01

272

Intensive Titan exploration begins.  

PubMed

The Cassini Orbiter spacecraft first skimmed through the tenuous upper atmosphere of Titan on 26 October 2004. This moon of Saturn is unique in our solar system, with a dense nitrogen atmosphere that is cold enough in places to rain methane, the feedstock for the atmospheric chemistry that produces hydrocarbons, nitrile compounds, and Titan's orange haze. The data returned from this flyby supply new information on the magnetic field and plasma environment around Titan, expose new facets of the dynamics and chemistry of Titan's atmosphere, and provide the first glimpses of what appears to be a complex, fluid-processed, geologically young Titan surface. PMID:15890870

Mahaffy, Paul R

2005-05-13

273

Measured displacement energies of oxygen ions in titanates and zirconates  

Microsoft Academic Search

Optical emission spectra in the 300–700 nm range were collected from four perovskite-structured materials (CaTiO3, SrTiO3, BaTiO3 and CaZrO3), a pyrochlore-structured material (La2Zr2O7) and zirconolite (CaZrTi2O7), using either a Febetron 706 variable energy pulsed-electron-beam generator (pulse duration 3 ns) or a Vickers pulsed-electron LINAC (pulse duration 0.5 ?s). The long-lived emissions (up to microseconds after the electron pulse) consist of

Katherine L Smith; Michael Colella; Ronald Cooper; Eric R Vance

2003-01-01

274

The Titan Space Launch System  

Microsoft Academic Search

The Titan III Space Launch Vehicle (SLV) System providing reliable fast response booster capability is discussed. Early Titans, including Titans I and II and the Gemini launch vehicle are described, and the elements of the Titan III, including the upper stages, payload fairings, and launch facilities are presented. The liquid boost module for STS performance augmentation and the Titan 34D

J. T. Keeley

1981-01-01

275

Origin of Titan's Atmosphere  

NASA Astrophysics Data System (ADS)

Titan has remarkable features - a dense N2 atmosphere and hydrological cycles of CH4 - that are resemble to those of Earth. How did the atmosphere develop on Titan? Was its origin similar to that of Earth’s atmosphere? Although these questions remain unsolved, the Cassini-Huygens mission has provided important clues to understand the origin of Titan’s atmosphere. 1) The low abundance of primordial Ar indicates that Titan’s N2 would have been delivered in less volatile form, probably as NH3. 2) Titan’s interior may have been only partially differentiated or may consist of low-density rock materials, suggesting that the interior would have been cooler than previously thought. 3) Observations of Enceladus’ plume suggest that the chemical composition of building materials of the Saturnian satellites would have been similar to that of comets; i.e., CO2 would have been more abundant than CH4 in the satellitesimals. 4) Relatively young surface age, high levels of radiogenic Ar, and the absence of global CH4 oceans suggest recent degassing of CH4 from the interior. The observations 1) and 2) imply the importance of conversion process of NH3 to N2 on Titan while maintaining the interior cool. However, because all of proposed mechanisms converting NH3 to N2 (e.g., photolysis, shock heating, and impact) also dissociate primordial CO2 to CO, the lack of abundant CO in the present atmosphere is a big issue. Furthermore, if Titan’s interior is undifferentiated, this is apparently inconsistent with a view of young surface and recent degassing. So far, there is no model which explains the above observations consistently. In this paper, we review the proposed mechanisms to create a N2-CH4 atmosphere on Titan and discuss new problems raised by Cassini. Then, we will discuss a plausible history of Titan’s atmosphere on the basis of the new observations.

Sekine, Yasuhito

2012-04-01

276

Titan Aerosols  

NASA Astrophysics Data System (ADS)

Titan s atmospheric haze is the most prominent feature of its atmosphere obscuring the surface at visible wavelengths and responsible for most of the absorbed solar energy Photochemical models and laboratory simulations past and present point to organic and nitrile composition for most of the haze with possible embedded hydrocarbon condensates such as liquid ethane at various altitudes Measurements made from instruments on the Huygens probe and Cassini orbiter within the last two years have added valuable information leading to some changes in our thinking about the distribution of the haze and the properties of the haze particles The Cassini Imaging Science Subsystem ISS discovered a distinct layer near 500 Km altitude whereas the layer seen in the voyager cameras was at a much lower altitude The ISS also found many thin haze layers between 300 and 450 Km in the north polar hood The Descent Imager and Spectral-Radiometer DISR on t he Huygens Probe made many in situ measurements with spectrometers and a solar aureole camera These show that the haze at the landing site is optically thicker than some models predicted in the near-infrared thinner than predicted in the blue and with a spectral variation much flatter than predicted from previous studies DISR measurements also show an increase in the particle single scatter albedo below 80 Km altitude and a break in the slope of the haze concentration near 80 Km Below 80 Km the particle number density is approximately constant with altitude whereas above 80 Km the particle number density decreases in

West, R. A.

277

Fission fragment damage in zircon  

Microsoft Academic Search

X-ray diffraction, electron microscope and optical studies have been : ade on zircons damaged by fission fragments derived from the action of neutrons on uranium impurities in the zircon lattice. A dosage of about 10 fission events · cm was required to produce diffuse x-ray scattering, observable by conventional photographic methods, and a dosage of about 10 fission events ·

E. R. Vance; J. N. Boland

1975-01-01

278

Etching fission tracks in zircons  

USGS Publications Warehouse

A new technique has been developed whereby fission tracks can be etched in zircon with a solution of sodium hydroxide at 220??C. Etching time varied between 15 minutes and 5 hours. Colored zircon required less etching time than the colorless varieties.

Naeser, C. W.

1969-01-01

279

From Titan’s tholins to Titan’s aerosols: Isotopic study and chemical evolution at Titan’s surface  

NASA Astrophysics Data System (ADS)

In the present work, we focused on the possible isotopic fractionation of carbon during the processes involved in the formation of Titan’s tholins. We present the first results obtained on the 12C/13C isotopic ratios measured on Titan’s tholins synthesized in laboratory with cold plasma discharges. Measurements of isotopic ratio 12C/13C, done both on tholins and on the initial gas mixture (N2:CH4 (98:2)) used to produce them, do not show any evident deficit or enrichment in 13C relatively to 12C in the synthesized tholins, compared to the initial gas mixture. This observation allows to go further in the analyses of the ACP experiment data, including part of the Cassini Huygens mission. We also focused on the chemical evolution of the aerosols at Titan surface by studying species coming from acid hydrolysis treatment of Titan’s tholins. Preliminary results show a wide diversity of chemical families, going from carboxylic acids to amino acids. Advanced studies could bring at short-term clues on the still unidentified mixture that induces the decrease of the reflectivity as measure by the DISR instrument [Tomasko, M.G., Archinal, B., Becker, T., Bézard, B., Bushroe, M., Combes, M., Cook, D., Coustenis, A., de Bergh, C., Dafoe, L.E., Doose, L., Douté, S., Eibl, A., Engel, S., Gliem, F., Grieger, B., Holso, K., Howington-Kraus, E., Karkoschka, E., Keller, H.U., Kirk, R., Kramm, R., Küppers, M., Lanagan, P., Lellouch, E., Lemmon, M., Lunine, J., McFarlane, E., Moores, J., Prout, G.M., Rizk, B., Rosiek, M., Rueffer, P., Schröder, S.E., Schmitt, B., See, C., Smith, P., Soderblom, L., Thomas, N., West, R. Rain, winds and haze during the Huygens probe’s descent to Titan’s surface. Nature 438(7069), 765 778, 2005]. At longer-term it could allow to better understand the possible chemical evolution of the Titan’s aerosols after falling down at the surface when brought into contact with water.

Nguyen, Mai-Julie; Raulin, François; Coll, Patrice; Derenne, Sylvie; Szopa, Cyril; Cernogora, Guy; Israël, Guy; Bernard, Jean-Michel

2008-07-01

280

Titan: an exogenic world?  

NASA Astrophysics Data System (ADS)

Titan's may be a world whose landscape is shaped by exogenic processes, with a relatively inactive interior and minor or negligible endogenic activity. Those landforms on Titan that are unambiguously identifiable can all be explained by exogenic processes (aeolian, fluvial, impact cratering, and mass wasting). Previous suggestions of endogenically produced cryovolcanic constructs and flows have been, without exception, lack conclusive diagnostic evidence. Minor tectonic activity could be driven by global thermal evolution or external forcing, rather than by active interior processes. A geologically quiescent interior is consistent with geophysical inferences. Titan might be most akin to Callisto with weather. We do not aim to disprove the existence of any and all endogenic activity on Titan, but instead to inject a necessary level of caution into the discussion. The hypothesis of Titan as a predominantly exogenic world can be tested through additional Cassini observations and analyses of putative cryovolcanic features, geophysical and thermal modeling of Titan's interior evolution, modeling of icy satellite landscape evolution that is shaped by exogenic processes alone, and consideration of possible means for replenishing Titan's atmospheric methane that do not rely on cryovolcanism. If Titan displays regions of degraded ancient cratered terrain (such as may be the case in Xanadu around 90°W), then this would have significant implications for Titan's history. Martian fluvially degraded cratered terrain still exhibits craters because fluvial activity largely ceased soon after the curtailment of heavy bombardment. For Titan to have such terrains and ongoing fluvial activity would imply at least three possible explanations: (1) alkane fluvial erosion on Titan is extremely inefficient relative to that by water on the Earth and Mars, or (2) fluvial erosion very rarely occurs on some regions on Titan; or (3) it has started raining on Titan only in geologically recent times.

Moore, Jeffrey M.; Pappalardo, Robert T.; Howard, Alan D.; Schenk, Paul M.

2010-04-01

281

Zircon growth in shear zones  

NASA Astrophysics Data System (ADS)

The possibility of direct dating of the deformation process is critical for understanding of orogenic belts evolution. Establishing the age of deformation by isotopic methods is indispensable in the case of uneven deformation overlapping, when later deformation inherits the structural plan of the early strains, and to distinguish them on the basis of the structural data only is impossible. A good example of zircon from the shear zones is zircon formed under the eclogite facies conditions. On the one hand, the composition of zircon speaks about its formation simultaneously to eclogitic paragenesis (Rubatto, Herman, 1999; Rubatto et al., 2003). On the other hand, geological studies show that mineral reactions of eclogitization are often held only in areas of shear deformations, which provides access of fluid to the rocks (Austrheim, 1987; Jamtveit et al., 2000; Bingen et al., 2004). Zircons from mafic and ultramafic rocks of the Tanaelv and Kolvitsa belts (Kola Peninsula, the Baltic Shield) have showed that the metamorphic zircon growth is probably controlled by the metamorphic fluid regime, as evidenced by an increase of zircon quantity with the degree of shearing. The internal structure of zircon crystals can provide an evidence of zircon growth synchronous with shearing. The studied crystals have a sector zoning and often specific "patchy" zoning (Fig. 1), which speaks about rapid change of growth conditions. Such internal structure can be compared with the "snowball" garnet structure reflecting the rotation of crystals during their growth under a shift. Rapidly changing crystallization conditions can also be associated with a small amount of fluid, where supersaturation is changing even at a constant temperature. Thus, the growth of metamorphic zircon in shear zones is more likely to occur in the fluid flow synchronous with deformation. A distinctive feature of zircons in these conditions is isometric shape and sector "patchy" zoning. The work was supported by Russian Foundation of Basic Research (project: 13-05-00035.) and the DES-6 program.

Kaulina, Tatiana

2013-04-01

282

Pneumatic flow control valve using particle excitation by PZT transducer  

Microsoft Academic Search

This paper reports a flow control valve for pneumatic actuators. This flow control valve has a lightweight and simple structure using particle excitation by PZT transducer, which is driven at resonance mode and it can be used as a variable speed controller for pneumatic actuators. A PZT transducer has been used for controlling flow rate in this study. The flow

Daisuke Hirooka; Koichi Suzumori; Takefumi Kanda

2009-01-01

283

MEMS-based thick film PZT vibrational energy harvester  

Microsoft Academic Search

We present a MEMS-based unimorph silicon\\/PZT thick film vibrational energy harvester with an integrated proof mass. We have developed a process that allows fabrication of high performance silicon based energy harvesters with a yield higher than 90%. The process comprises a KOH etch using a mechanical front side protection of an SOI wafer with screen printed PZT thick film. The

A. Lei; R. Xu; A. Thyssen; A. C. Stoot; T. L. Christiansen; K. Hansen; R. Lou-Moller; E. V. Thomsen; K. Birkelund

2011-01-01

284

Electrostriction in PZT-family antiferroelectrics  

Microsoft Academic Search

The elastic strain associated with the field-induced transition from an antiferroelectric phase to a ferroelectric one has been measured at several temperatures in a PZT-family ceramic Pb0·99Nb0·02 [(Zr0·6Sn0·4)0·94Ti0·06]0·98 O3. Reproducible large strain change of about ??\\/?? due to the forced transition may be promising for digital microdisplacement transducers. So-called “inverse hysteresis'’in the strain curve is observed in a temperature range

K. Uchino; S. Nomura

1983-01-01

285

Dynamics of Titan’s thermosphere  

Microsoft Academic Search

We estimate the wind speeds in Titan’s thermosphere by considering the various terms of the wind equation, without actually solving it, with a view to anticipating what might be observed by the Cassini spacecraft in 2004. The winds, which are driven by horizontal pressure gradients produced by solar heating, are controlled in the Earth’s thermosphere by ion-drag and coriolis force,

H. Rishbeth; R. V. Yelle; M. Mendillo

2000-01-01

286

Titanic: Discovery Channel  

NSDL National Science Digital Library

RMS Titanic raised a 23- by 14-foot section of the Titanic's outer hull this week, and the Discovery Channel, who helped sponsor the expedition, will be webcasting live from the interior of the Titanic via robot cameras August 16 at 8:00 and 10:00 p.m. (Eastern Time). In addition to their live webcase, the Discovery Channel site (discussed in the December 5, 1997 issue of the Scout Report) features virtual reality tours of sections of the Titanic before and after its crash, quicktime videos of the expeditions, a computer animated simulation of the crash, and more.

287

Zircon Recycling in Arc Intrusions  

NASA Astrophysics Data System (ADS)

Recycling of zircon has been well established in arc intrusions and arc volcanoes, but a better understanding of where and how zircons are recycled can help illuminate how arc magma systems are constructed. To that end, we are conducting age, trace element (including Ti-in-zircon temperatures; TzrnTi) and isotopic studies of zircons from the Late Cretaceous (95-85 Ma) Tuolumne Intrusive Suite (TIS) in the Sierra Nevada Batholith (CA). Within the TIS zircons inherited from ancient basement sources and/or distinctly older host rocks are uncommon, but recycled zircon antecrysts from earlier periods of TIS-related magmatism are common and conspicuous in the inner and two most voluminous units of the TIS, the Half Dome and Cathedral Peak Granodiorites. All TIS units have low bulk Zr ([Zr]<150 ppm) and thus low calculated zircon saturation temperatures (Tzrnsat). Within the Half Dome and Cathedral Peak, TzrnTi values are predominantly at or below average Tzrnsat, and there is no apparent correlation between age and TzrnTi. At temperatures appropriate for granodiorite/tonalite melt generation (at or above biotite dehydration; >825°C), [Zr] in the TIS is a factor of 2 to 3 lower than saturation values. Low [Zr] in TIS rocks might be attributed to a very limited supply of zircon in the source, by disequilibrium melting and rapid melt extraction [1], by melting reactions involving formation of other phases that can incorporate appreciable Zr [2], or by removal of zircon at an earlier stage of magma evolution. Based on a preliminary compilation of literature data, low [Zr] is common to Late Cretaceous N.A. Cordilleran granodioritic/tonalitic intrusions (typically <200 ppm and frequently 100-150 ppm for individual large intrusions or intrusive suites). We infer from this that [Zr] in anatectic melts is probably not limited by zircon supply and is primarily controlled by melting parameters. Comparison of the data from TIS with one of these intrusions, the smaller but otherwise similar Late Cretaceous Bear Lake Intrusive Suite (BLIS) in the San Bernardino Mountains (CA), is especially illuminating. Like the TIS the BLIS zircons also have low TzrnTi values (at or below Tzrnsat). However, unlike in the TIS, inherited zircons (or zircon cores) are common (BLIS is intruded into Paleoproterozoic basement). This comparison suggests that lack of abundant inherited or xenocrystic zircon in TIS rocks may be a function of whether they are in high abundance in the melt source or host rocks rather than strong initial undersaturation, and that low [Zr] might reflect melting at temperatures below biotite or amphibole dehydration. The high abundance of zircons with low TzrnTi could also reflect low anatectic temperatures as intermediate-felsic magmas that are initially undersaturated should be dominated by zircons with TzrnTi > Tzrnsat [3]. A corollary is that slightly older zircon antecrysts that are common in the inner units of the TIS could be considered inherited if they are derived from remelting of slightly older intrusions. Remelting at such low temperatures in the arc would require a source of external water. Refs: [1] Sawyer, J.Pet 32:701-738; [2] Fraser et al, Geology 25:607-610; [3] Harrison et al, Geology 35:635- 638

Miller, J.; Barth, A.; Matzel, J.; Wooden, J.; Burgess, S.

2008-12-01

288

Effect of acetylacetone on the preparation of PZT materials in sol–gel processing  

Microsoft Academic Search

Sol–gel processing is an advantageous route to produce PZT thin film materials with high quality. PZT powders and thin films with good properties were fabricated by sol–gel processing, using acetylacetone as modifier, in the study. The morphologies of PZT powders and thin films were observed by field emission microscopy, and the dielectric and properties of the PZT thin films were

Luqian Weng; Xujin Bao; Kwesi Sagoe-Crentsil

2002-01-01

289

Titan: an exogenic world?  

Microsoft Academic Search

Titan's may be a world whose landscape is shaped by exogenic processes, with a relatively inactive interior and minor or negligible endogenic activity. Those landforms on Titan that are unambiguously identifiable can all be explained by exogenic processes (aeolian, fluvial, impact cratering, and mass wasting). Previous suggestions of endogenically produced cryovolcanic constructs and flows have been, without exception, lack conclusive

Jeffrey M. Moore; Robert T. Pappalardo; Alan D. Howard; Paul M. Schenk

2010-01-01

290

Titan: Callisto With Weather?  

Microsoft Academic Search

Instead of being endogenically active, Titan's interior may be cold and dead. Those landforms on Titan that are unambiguously identifiable can all be explained by exogenic processes (aeolian, fluvial, impact cratering, and mass wasting). At the scale of available imaging data, the surface is dominated by vast dune ergs and by fluvial erosion, transportation, and deposition. The sparse distribution of

J. M. Moore; R. T. Pappalardo

2008-01-01

291

Clash of the Titans  

ERIC Educational Resources Information Center

|WebQuests and the 5E learning cycle are titans of the science classroom. These popular inquiry-based strategies are most often used as separate entities, but the author has discovered that using a combined WebQuest and 5E learning cycle format taps into the inherent power and potential of both strategies. In the lesson, "Clash of the Titans,"…

Subramaniam, Karthigeyan

2010-01-01

292

Recrystallisation of Strontium Titanate  

Microsoft Academic Search

The recrystallisation rate of amorphous strontium titanate is dramatically enhanced by thermal annealing in water vapour as compared with a dry ambient. Time resolved optical reflectivity (TRR) has been combined with Rutherford backscattering spectrometry (RBS) and ion channelling to investigate this effect. Thin amorphous films were produced on single crystal substrates of (100) strontium titanate by ion bombardment. Specimens were

Todd William Simpson

1993-01-01

293

Preparation of PZT ferroelectric thick films by nanopowder-metal-organic decomposition process  

Microsoft Academic Search

In this paper, a modified metal-organic decomposition (MOD) process has been developed for the fabrication of PZT thick films. Nano-sized PZT powders, around 5–15 nm, were first synthesized using hydrolysis of PZT alkoxide precursors, and then incorporated into a precursor containing PZT-carboxylates (0.2 M), followed by spin-coating process. The properties of nano-powder incorporated PZT precursors solution influences the spin-coating characteristics

Kuo-shung Liu; Yai-yei Huang; Wen-jiun Lin; Tsang-lan Lin; I-nan Lin

2000-01-01

294

Titan's Exotic Weather  

NASA Astrophysics Data System (ADS)

Images of Titan, taken during the joint NASA and European Space Agency Cassini-Huygens mission, invoke a feeling of familiarity: washes wind downhill to damp lakebeds; massive cumuli form and quickly dissipate, suggestive of rain; and dark oval regions resemble lakes. These features arise from Titan's unique similarity with Earth: both cycle liquid between their surfaces and atmospheres, but in Titan's cool atmosphere it is methane that exists as a gas, liquid, and ice. While Titan enticingly resembles Earth, its atmosphere is 10 times thicker, so that its radiative time constant near the surface exceeds a Titan year, and prohibits large thermal gradients and seasonal surface temperature variations exceeding 3K. Titan also lacks oceans - central to Earth's climate - and instead stores much of its condensible in its atmosphere. As a result, Titan's weather differs remarkably from Earth's. Evidence for this difference appears in the location of Titan's large clouds, which frequent a narrow band at 40S latitude and a region within 30 latitude of the S. Pole. Ground-based and Cassini observations, combined with thermodynamic considerations, indicate that we are seeing large convective cloud systems. Detailed cloud models and general circulation models further suggest that these are severe rain storms, which will migrate with the change in season. Outside these migrating "gypsy" cloud bands, the atmosphere appears to be calm, humid and thus frequented by thin stratiform clouds. An intriguingly alien environment is predicted. Yet, the combined effects of Titan's patchy wet surface, atmospheric tides, possible ice volcanoes, and detailed seasonal variations remain unclear as we have witnessed only one season so far. This talk will review observations of Titan's lower atmosphere and modeling efforts to explain the observations, and explore the questions that still elude us.

Griffith, Caitlin A.

2006-09-01

295

Dielectric and ferroelectric analysis of nanoparticle/nanocrystalline barium titanate and PLZT.  

SciTech Connect

Attractive for numerous technological applications, ferroelectronic oxides constitute an important class of multifunctional compounds. Intense experimental efforts have been made recently in synthesizing, processing and understanding ferroelectric nanostructures. This work will present the systematic characterization and optimization of barium titanate and lead lanthanum zirconate titanate nanoparticle based ceramics. The nanoparticles have been synthesized using several solution and pH-based synthesis processing routes and employed to fabricate polycrystalline ceramic and nanocomposite based components. The dielectric and ferroelectric properties of these various components have been gauged by impedance analysis and electromechanical response and will be discussed.

DiAntonio, Christopher Brian; Yang, Pin; Chavez, Tom P.; Winter, Michael R.; Monson, Todd C.; Roesler, Alexander William

2010-07-01

296

Recrystallisation of oscillatory zoned zircon: some geochronological and petrological implications  

Microsoft Academic Search

Oscillatory zoning is a common feature in zircons from acid igneous rocks and is believed to form during crystallisation of zircons from a magma by a mechanism which is not yet understood. Many zircons with oscillatory zoning also show a patchwork replacement of zoned by unzoned zircon. The unzoned zircon occurs as rounded, transgressive patches distributed throughout the zoned zircon

R. T. Pidgeon

1992-01-01

297

Surface-modified lead-zirconium-titanate system for solution-processed ferroelectric-gate thin-film transistors  

NASA Astrophysics Data System (ADS)

We propose the use of a La2O3 (LO) film as the capping layer for improvement of a semiconductor/insulator interface in a solution-processed indium-tin-oxide (ITO) ferroelectric-gate thin-film transistor (FGT) device. It is demonstrated that the LO layer acts as a good barrier film not only for preventing the interdiffusion between the ITO semiconductor and lead-zirconium-titanate (PZT) insulator layers, but also for stabilizing the PZT surface structure. The fabricated FGT device exhibited high I on/ I off, large M w, high ? FE and improved retention time of about 109, 3.5 V, 7.94 cm2 V-1 s-1 and 1 day, respectively, which are comparable to or better than those obtained with FGTs fabricated by means of conventional vacuum processes. We also point out that the key origin of the interface improvement is likely due to the incorporation of La into the PZT system, forming a La surface-modified PZT system which is more stable than the pure PZT in terms of Pb volatility and formation of oxygen vacancies.

Phan, Tue Trong; Miyasako, Takaaki; Higashimine, Koichi; Tokumitsu, Eisuke; Shimoda, Tatsuya

2013-11-01

298

The astrobiology of Titan  

NASA Astrophysics Data System (ADS)

Largest satellite of Saturn and the only satellite in the solar system having a dense atmosphere, Titan is one of the key planetary bodies for astrobiological studies, due to several aspects: Its analogies with planet Earth, in spite of much lower temperatures, The Cassini-Huygens data have largely confirmed the many analogies between Titan and our own planet. Both have similar vertical temperature profiles, (although much colder, of course, on Titan). Both have condensable and non condensable greenhouse gases in their atmosphere. Both are geologically very active. Furthermore, the data also suggest strongly the presence of a methane cycle on Titan analogous to the water cycle on Earth. The presence of an active organic chemistry, involving several of the key compounds of prebiotic chemistry. The recent data obtained from the Huygens instruments show that the organic matter in Titan low atmosphere (stratosphere and troposphere) is mainly concentrated in the aerosol particles. Because of the vertical temperature profile in this part of the atmosphere, most of the volatile organics are probably mainly condensed on the aerosol particles. The nucleus of these particles seems to be made of complex macromolecular organic matter, well mimicked in the laboratory by the "Titan's tholins". Now, laboratory tholins are known to release many organic compounds of biological interest, such as amino acids and purine and pyrimidine bases, when they are in contact with liquid water. Such hydrolysis may have occurred on the surface of Titan, in the bodies of liquid water which episodically may form on Titan's surface from meteoritic and cometary impacts. The formation of biologically interesting compounds may also occur in the deep water ocean, from the hydrolysis of complex organic material included in the chrondritic matter accreted during the formation of Titan. The possible emergence and persistence of Life on Titan 1 All ingredients which seems necessary for Life are present on Titan : • liquid water : permanently as a deep sub-surface ocean, and even episodically on the surface, • organic matter : in the internal structure, from chondritic materials, and in the atmosphere and on the surface, from the atmospheric organic chemistry • and energy : in the atmosphere (solar UV photons, energetic electrons from Saturn magnetosphere and cosmic rays) and, probably, in the environment of the sub-surface ocean (radioactive nuclei in the deep interior and tidal energy dissipation) as also supported by the likely presence of cryovolcanism on the surface Thus, it cannot be excluded that life may have emerged on or in Titan. In spite of the extreme conditions in this environment life may have been able to adapt and to persist. Many data are still expected from the Cassini-Huygens mission and future astrobiological exploration mission of Titan are now under consideration. Nevertheless, Titan already looks like another word, with an active prebiotic-like chemistry, but in the absence of permanent liquid water, on the surface: a natural laboratory for prebiotic-like chemistry. References. Fortes, A.D. (2000), `Exobiological implications of a possible ammonia-water ocean inside Titan', Icarus 146, 444-452 Raulin, F. (2005), `Exo-Astrobiological Aspects of Europa and Titan: From Observations to Speculations', Space Science Review 116 (1-2), 471-496. Nature, (2005), `The Huygens probe on Titan', 8 News & Views, Articles and Letters 438, 756-802 Schulze-Makuch, D., and Grinspoon D.H. (2005), `Biologically enhanced energy and carbon cycling on Titan?',Astrobiology 5, 560-567. 2

Raulin, F.; Coll, P.; Cabane, M.; Hebrard, E.; Israel, G.; Nguyen, M.-J.; Szopa, C.; Gpcos Team

299

ISO Spectroscopy of Titan  

NASA Astrophysics Data System (ADS)

In the spectroscopic mode, Titan was observed by ISO in 1997 by SWS/Grating, PHT-S and CAM/CVF. The combination of these data provides Titan's spectrum from 5 to 17 and from 2.5 to 5 ?m with resolving powers ranging from 40 (CAM/CVF) to 2000 (SWS). The analysis of the spectra provides information on (a) Titan's atmospheric structure (temperature and composition) and (b) Titan's surface (through the emission observed in the 2.9-micron window). In this paper we concentrate on the 7 to 9 and 2.5 to 5 micron regions. A temperature profile for Titan's disk is inferred from the analysis of the 7.7 ?m CH4 band. The CH3D abundance is estimated to be 7.5 (+4.0-3.7) × 10-6, for a D/H ratio of 9.5 (+9.5-1.0) × 10-5. The 2.9 methane ``window'' on Titan is observed in its full shape for the first time. It shows two peaks at 2.7 and 2.8 ?m, and an absorption feature at 2.75 ?m, which may be the spectral signature of a surface component on Titan.

Coustenis, A.; Salama, A.; Lellouch, E.; Encrenaz, Th.; Schulz, B.; Feuchtgruber, H.; Gautier, D.; Ott, S.; de Graauw, Th.; Kessler, M. F.

2000-11-01

300

Materials interactions in the integration of PZT ferroelectric capacitors  

Microsoft Academic Search

Investigations of materials interactions that complicate the integration of PZT ferroelectric capacitors into CMOS technologies are discussed. These include interactions within the Pt\\/Ti electrodes structure, the reactions of sol-gel deposited PZT during crystallization with various underlying dielectrics (SiO2, Si3N4, Al2O3, and TiO2), and the impact of other integrated circuit processes on fabricated capacitors.

R. E. Jones Jr; P. D. Maniar; A. C. Campbell; R. Moazzami; J. L. Dupuie; R. B. Gregory; M. L. Kottke; M. L. Bozack; J. R. Williams; J. M. Ferrero

1995-01-01

301

Design of a PZT-actuated proportional drum brake  

Microsoft Academic Search

Presents the design of a piezoelectric-ceramic (PZT)-stack-actuated brake that is similar to a magnetic particle brake in dynamic range, size, weight, and cost, while providing a significantly larger bandwidth and requiring significantly less electrical power for a given continuous torque output. The device is essentially a single-pad drum brake that is actuated with a PZT-stack actuator. A significant component of

Michael Gogola; Michael Goldfarb

1999-01-01

302

Standing wave brass-PZT square tubular ultrasonic motor.  

PubMed

This paper reports a standing wave brass-PZT tubular ultrasonic motor. The motor is composed of a brass square tube with two teeth on each tube end. Four PZT plates are attached to the outside walls of the brass tube. The motor requires only one driving signal to excite vibration in a single bending mode to generate reciprocating diagonal trajectories of teeth on the brass tube ends, which drive the motor to rotate. Bi-directional rotation is achieved by exciting different pairs of PZT plates to switch the bending vibration direction. Through using the brass-PZT tube structure, the motor can take high magnitude vibration to achieve a high output power in comparison to PZT tube based ultrasonic motors. Prototypes are fabricated and tested. The dimension of the brass-PZT tube is 3.975mm×3.975mm×16mm. Measured performance is a no-load speed of >1000RPM, a stall torque of 370?Nm and a maximum output power of 16 mW when a sinusoidal driving voltage of 50V is applied. The working frequencies of the motor are 46,050Hz (clockwise) and 46,200Hz (counter-clockwise). PMID:22673298

Park, Soonho; He, Siyuan

2012-05-16

303

Tectonic features on Titan  

NASA Astrophysics Data System (ADS)

This research is based on the exploration of tectonic patterns on Titan from a global perspective. Several moons in the outer solar system display known stress fields driven or modified by global forces which affect patterns of tectonism. Patterns such as these are seen in Europa's tidal forces, Enceladus' tiger strips, and Ganymede's global expansion. Given its proximity to Saturn, as well as its eccentric orbit, tectonic features and global stresses may be present on Titan as well. Titan displays visible tectonic structures, such as mountain chains along its equator (Radebaugh et al. 2007), as well as the unexplored Virgae.

Cook, C.; Barnes, J.

2011-10-01

304

The TITAN reversed-field-pinch fusion reactor study  

SciTech Connect

This report discusses the following topics: overview of titan-2 design; titan-2 fusion-power-core engineering; titan-2 divertor engineering; titan-2 tritium systems; titan-2 safety design and radioactive-waste disposal; and titan-2 maintenance procedures.

Not Available

1990-01-01

305

Modified cofiring behaviors between PMN-PNN-PZT piezoelectric ceramics and PZT-doped 70Ag–30Pd alloy metallization  

Microsoft Academic Search

The cofiring behaviors between PMN-PNN-PZT piezoelectric ceramics and 70Ag–30Pd electrode paste were investigated in view of sintering densification behavior, thermal expansion coefficients (TEC) and interfacial physical integrity. The results showed that mismatched cofiring characteristics have greatly affected the reliability of multilayer piezoelectric ceramic devices. The application of a PZT additive to 70Ag–30Pd electrode technology has markedly improved the above-mentioned cofiring

Ruzhong Zuo; Longtu Li; Zhilun Gui

2002-01-01

306

Titan's "Hot Cross Bun": A Titan Laccolith?  

NASA Astrophysics Data System (ADS)

Cassini’s RADAR instrument acquired Synthetic Aperture Radar data during the T83 flyby on May 22, 2012. The data showed a feature centered at 38.5N, 203W that resembles a “hot cross bun”. This type of feature has not been seen on Titan before, even though 52% of Titan’s surface has been imaged using SAR. The feature, approximately 100 km across, is mostly radar bright but the cross pattern, interpreted to be extensional fractures, located roughly at the center of the brighter area, appears darker at radar wavelengths (2.3 cm). Radar illumination of the image indicates that the fractures are lower in elevation than the surrounding bright region. The morphology of the region is markedly similar to that of a 30-km dome-shaped feature on Venus that lies at the summit of the Kunapipi volcano. The Venus feature is interpreted to be the result of intrusion of magma at the summit of the volcano [1]. A similar feature, interpreted as a laccolith, is seen on the Moon near the crater Ramsden [2]. The lunar feature, imaged by the Lunar Reconnaissance Orbiter, shows the cross-shaped depression over a 300 m high rise. No topographic data for the feature on Titan are available at this time, but the morphology seen by the SAR data suggests that the feature may have been formed by material pushing up from below. Laccoliths form when an igneous intrusion splits apart two strata, resulting in a domeline structure. This previously unknown type of structure on Titan may be yet another indication of cryovolcanism. [1] Stofan, E.R., et al, Icarus, 152, 75-95, 2001. [2] Wichman, R.W. and Schultz, P. H. (1996). Icarus, 122, Issue 1, July 1996, pages 193-199. doi:10.1006/icar.1996.0118

Lopes, Rosaly M. C.; Stofan, E. R.; Wall, S. D.; Wood, C.; Kirk, R. L.; Lucas, A.; Mitchell, K. L.; Lunine, J. I.; Turtle, E. P.; Radebaugh, J.; Malaska, M.; Cassini RADAR Team

2012-10-01

307

Crystallization thermometers for zircon and rutile  

Microsoft Academic Search

Zircon and rutile are common accessory minerals whose essential structural constituents, Zr, Ti, and Si can replace one another to a limited extent. Here we present the combined results of high pressure–temperature experiments and analyses of natural zircons and rutile crystals that reveal systematic changes with temperature in the uptake of Ti in zircon and Zr in rutile. Detailed calibrations

E. B. Watson; D. A. Wark; J. B. Thomas

2006-01-01

308

Titan IV Requirements.  

National Technical Information Service (NTIS)

The objective of the audit was to evaluate the requirements for Titan IV launch vehicles to support classified and unclassified systems. The audit determined whether requisite system specifications and needs were efficiently and effectively incorporated i...

W. F. Thomas C. M. Santoni L. G. O'Daniel P. B. Shepphard R. Bertocchi

1994-01-01

309

Titan IV Program.  

National Technical Information Service (NTIS)

The Titan IV is an unmanned, expendable launch vehicle that complements the space shuttle and ensures access to space for national security payloads. The target and ceiling prices for the single ceiling fixed-price- incentive contract for development, pro...

1992-01-01

310

Raising the Titanic.  

ERIC Educational Resources Information Center

|Described is an activity in which groups of students investigate engineering principles by writing a feasibility study to raise the luxury liner, Titanic. The problem statement and directions, and suggestions for problem solutions are included. (CW)|

Baker, Romona

1990-01-01

311

The Titan Space Launch System  

NASA Astrophysics Data System (ADS)

The Titan III Space Launch Vehicle (SLV) System providing reliable fast response booster capability is discussed. Early Titans, including Titans I and II and the Gemini launch vehicle are described, and the elements of the Titan III, including the upper stages, payload fairings, and launch facilities are presented. The liquid boost module for STS performance augmentation and the Titan 34D SLV System are also discussed. The Titan III SLV System demonstrates excellent versatility while maintaining a high reliability record during thirteen years of operational flights, and provides optional use of solid thrust augmentation and launch sites on both Coasts.

Keeley, J. T.

1981-04-01

312

Titan's Ammonia Feature  

NASA Astrophysics Data System (ADS)

NH3 has long been considered an important component in the formation and evolution of the outer planet satellites. NH3 is particularly important for Titan, since it may serve as the reservoir for atmospheric nitrogen. A brightening seen on Titan starting in 2004 may arise from a transient low-lying fog or surface coating of ammonia. The spectral shape suggests the ammonia is anhydrous, a molecule that hydrates quickly in the presence of water.

Smythe, W.; Nelson, R.; Boryta, M.; Choukroun, M.

2011-10-01

313

Georgians Died on Titanic  

Microsoft Academic Search

Hardly anyone remembers the Dona Paz or the Wilhelm Gustloff, but almost everyone knows about the Titanic. However, few know that four Georgians--three men and a woman--were aboard the doomed Titanic, and that the three men died in the catastrophe. The oldest of the men was a 67-year old philanthropist who many years earlier had lived in Georgia for almost

Wilkes Donald E. Jr

1994-01-01

314

Titan - Some new results  

SciTech Connect

New analyses of Voyager spectra of Titan have led to improvements in the determination of abundances of minor constituents as a function of latitude and altitude. Ground-based microwave observations have extended the Voyager results for HCN, and have demonstrated that CO is mysteriously deficient in the stratosphere. The origin of the CH4, CO, and N2 in Titan's atmosphere is still unresolved. Both primordial and evolutionary sources are compatible with the available evidence. 21 refs.

Owen, T.; Gautier, D.

1989-01-01

315

A comparative study of viscous polymer processed ceramics based on aqueous and non-aqueous binder systems  

Microsoft Academic Search

Lead zirconate titanate (PZT) is an important piezoelectric material which has wide range of applications as sensors, actuators and transducers. Various forms are required for different devices applications. In this work, extrusion and press forming of PZT ceramic rods and thick films produced via a viscous polymer processing (VPP) route have been investigated. The relationships between the rheology, microstructure and

B. Su; T. W. Button

2009-01-01

316

Soft Tissue Elastic Modulus Measurement and Tumor Detection Using Piezoelectric Fingers  

Microsoft Academic Search

We have investigated probing breast tumor in a lumpectomy sample using a newly developed piezoelectric finger (PEF). PEF is a piezoelectric cantile ver that consists of a top driving piezoelectric lead zirconate titanate (PZT) layer and a bottom sen sing PZT layer sandwiched to a middle stainless steel layer. A PEF can both apply a force and detect the corresponding

Hakki O. Yegingil; Wan Y. Shih; Waqas Anjum; Ari D. Brooks; Wei-Heng Shih

317

Advances in Piezoelectrically Actuated RF MEMS Switches and Phase Shifters  

Microsoft Academic Search

This report presents results on recent advances in piezoelectric actuated radio frequency (RF) microelectromechanical system (MEMS) devices including a temperature insensitive RF MEMS series switch and the demonstration of a 2-bit MEMS phase shifter incorporating PZT switches. Using lead zirconate titanate (PZT) thin films, modifications to our earlier designs resulted in a RF MEMS series switch operating at 10 V

R. G. Polcawich; D. Judy; J. S. Pulskamp; S. Trolier-McKinstry; M. Dubey

2007-01-01

318

Titan: An exogenic world?  

NASA Astrophysics Data System (ADS)

All landforms on Titan that are unambiguously identifiable can be explained by exogenic processes (aeolian, fluvial, impact cratering, and mass wasting). Previous suggestions of endogenically produced cryovolcanic constructs and flows have, without exception, lacked conclusive diagnostic evidence. The modification of sparse recognizable impact craters (themselves exogenic) can be explained by aeolian and fluvial erosion. Tectonic activity could be driven by global thermal evolution or external forcing, rather than by active interior processes. A lack of cryovolcanism would be consistent with geophysical inferences of a relatively quiescent interior: incomplete differentiation, only minor tidal heating, and possibly a lack of internal convection today. Titan might be most akin to Callisto with weather: an endogenically relatively inactive world with a cool interior. We do not aim to disprove the existence of any and all endogenic activity at Titan, nor to provide definitive alternative hypotheses for all landforms, but instead to inject a necessary level of caution into the discussion. The hypothesis of Titan as a predominantly exogenic world can be tested through additional Cassini observations and analyses of putative cryovolcanic features, geophysical and thermal modeling of Titan's interior evolution, modeling of icy satellite landscape evolution that is shaped by exogenic processes alone, and consideration of possible means for supplying Titan's atmospheric constituents that do not rely on cryovolcanism.

Moore, Jeffrey M.; Pappalardo, Robert T.

2011-04-01

319

The astrobiology of Titan  

NASA Astrophysics Data System (ADS)

The known organic environments in the solar system other than the Earth and certain meteorites are in the outer solar system. Those of astrobiological potential are Europa, Titan, and comets. Titan is of interest because its nitrogen-methane atmosphere generates hydrocarbons and nitriles which fall to the surface and are protected from damaging particle and UV radiation by a thick atmosphere. Further chemistry, including in the presence of transient and localized areas of cryovolcanic- or impact-generated liquid water, may proceed on the surface in staccato fashion over geologic time. The Cassini-Huygens mission will initiate the detailed exploration of Titan in 2004, and this fall NASA solicited mission concepts for post Cassini-Huygens missions to Titan. A focus group on the astrobiological exploration of Titan has been founded by the NASA Astrobiology Institute under the leadership of the author. It will provide science rationales from an astrobiological perspective on the future exploration of Titan, i.e. beyond Cassini-Huygens, through electronic discussions and workshops. Early results of the Focus Group will be described in this talk.

Lunine, J. I.

2003-12-01

320

Early History of Titan  

NASA Astrophysics Data System (ADS)

We revisit models for the early history of Titan. Our models are formed a few My after the production of calcium-aluminum inclusions (CAIs), consistent with the dates required by our thermophysical-dynamical modeling of Saturn's medium-sized satellites. Depending on the time of formation with respect to CAIs, the accretion timescale, and the available accretional energy, models of Titan's interior after accretion are partially to fully differentiated. At one extreme, the model Titan accretes incorporating a minimal amount of heat. This results in a relatively cold core that, over the long term, heats up and overturns, consistent with previous models of Titan. At the other extreme, a lot of heat is accreted. For this model of Titan complete differentiation quickly occurs, there is no core overturn, and conditions soon develop for silicate serpentinization and hydrothermal activity to occur. We identify the periods during which conditions are suitable for hydrothermal geochemistry leading to the production of molecular nitrogen from ammonia decomposition and methane from the Fischer-Tropfsch reaction. Key issues involve the storage of the reactants and products inside Titan, and mechanisms by which they are released to the surface. Acknowledgements: This work was carried out at the Jet Propulsion Laboratory- California Institute of Technology, under contract to NASA.

Matson, D.; Castillo, J.; Atreya, S.; Lunine, J.; Johnson, T.

2007-08-01

321

Determination of uranium in zircon  

USGS Publications Warehouse

A routine fluorimetric procedure is described for the determination of trace amounts of uranium in zircon. It employs the direct extraction of uranyl nitrate with ethyl acetate using phosphate as a retainer for zirconium. Submicrogram amounts or uranium are separated in the presence of 100,000 times the amount of zirconium. The modified procedure has been worked out using synthetic mixtures of known composition and zircon. Results of analyses have an accuracy of 97-98% of the contained uranium and a standard deviation of less than 2.5%. ?? 1959.

Cuttitta, F.; Daniels, G. J.

1959-01-01

322

PZT Actuated Seesaw SPDT RF MEMS Switch  

NASA Astrophysics Data System (ADS)

A low actuation voltage and no contact stiction are important factors in applying micro-electro-mechanical-system (MEMS) RF switches to mobile communication devices. Conventional electrostatic RF MEMS switches require several tens of voltages for actuation. In this paper we propose a piezoelectric actuated seesaw (PAS) RF MEMS switch which adopts Pb(Zr, Ti)O3 (PZT) actuators and seesaw cantilevers to meet the above requirements. The fundamental structures of PAS RF MEMS switches were designed, optimized, and fabricated. Through the developed process of PAS single pole double through (SPDT), RF MEMS switches were successfully fabricated on a 4'' wafer and they showed good electrical properties. The driving voltage was less than 5 volts and the insertion loss was -0.5dB and the isolation was -35dB at 5GHz. The maximum switching speed was about 5kHz. Thus these RF MEMS switches can be applicable to mobile communication devices or wireless multi-media devices at a frequency lower than 6GHz.

Lee, Dae-Sung; Jung, Suk-Won; Cho, Nam-Kyu; Kim, Won-Hyo; Seong, Woo-Kyeong; Park, Hyo-Derk

2006-04-01

323

Voltage bias influence on the converse magnetoelectric effect of PZT/terfenol-D/PZT laminates  

NASA Astrophysics Data System (ADS)

The converse magnetoelectric effect (CME) of a 2-mm-thick Pb(Zr0.52Ti0.48)O3 (PZT)/Tb0.30Dy0.7Fe2 (Terfenol-D)/PZT laminate subjected to an applied dc voltage bias has been investigated. Experimental data demonstrate that the CME coefficient ?CME (B/Vac)is highly dependent on the applied voltage bias. In the present work, the voltage bias is shown to increase the magnitude of magnetostriction in the Terfenol-D, which results in an increase in the magnitude and range of piezomagnetic coefficient and ?CME values. It is shown that ?CME can range from a minimum of 0.4 G/V at a voltage bias of -200 V to a value of 1.65 G/V at a voltage bias of 700 V. This range represents a greater than 400% change in the ?CME at a fixed magnetic field bias, the largest change in ?CME due to voltage bias yet reported. The expanded range is primarily caused by giant shifts in the piezomagnetic coefficient and not by nonlinearities in the piezoelectric coefficient.

Hockel, Joshua L.; Wu, Tao; Carman, Gregory P.

2011-03-01

324

Titan: Callisto With Weather?  

NASA Astrophysics Data System (ADS)

Instead of being endogenically active, Titan's interior may be cold and dead. Those landforms on Titan that are unambiguously identifiable can all be explained by exogenic processes (aeolian, fluvial, impact cratering, and mass wasting). At the scale of available imaging data, the surface is dominated by vast dune ergs and by fluvial erosion, transportation, and deposition. The sparse distribution of recognizable impact craters (themselves exogenic) is consistent with the presence of aeolian and fluvial activity sufficient to cover and or erode smaller craters, leaving only large ones. Previous suggestions of endogenically produced landforms have been, without exception, inconclusively identified. Features suggested to be cryovolcanic flows may be debris flows and other mass movements, facilitated by hydrocarbon-fluidized unconsolidated materials. Ganesa Macula has been suggested as a putative cryovolcanic dome, but it may simply be an impact structure that contains radar-dark dune or mass-wasted materials. Mountains, which are heavily modified by fluvial and mass wasting processes, could have formed as the scarps of large impact features and/or by slow contraction due to global cooling and freezing of an internal ammonia-water ocean, rather than by endogenically powered orogeny. A cold and inactive interior is consistent with an internal ammonia-water ocean, which has a peritectic temperature of 173K, easily obtained in Titan by radioactive decay alone in the absence of tidal heating. Titan's orbital eccentricity should have damped if its interior is warm and dissipative; instead, its high eccentricity can be ancient if the interior is assumed to be cold and non-dissipative. Indeed, it has been suggested that Titan may be non-hydrostatic, consistent with a thick ice shell and a cold and rigid interior. We suggest that the satellite most akin to Titan may be Callisto. Like Callisto, which may have formed relatively slowly in the outer circumjovian accretion disk, Titan might have accreted relatively cold. Without being in a forced resonance, Titan's interior may have never undergone significant tidal heating. Analogous to Callisto's tenuous CO2 atmosphere, believed to be generated by sublimation of interior ices, interior clathrated methane within Titan may slowly diffuse outward from the cold interior, rather than the atmosphere being replenished by cryovolcanism. The hypothesis that Titan is "Callisto with weather" -- with geological processes that are principally exogenic -- can be tested through geophysical and thermal modeling, and by modeling the evolution of landscapes that are shaped by exogenic processes alone.

Moore, J. M.; Pappalardo, R. T.

2008-12-01

325

Titan Saturn System Mission Instrumentation  

NASA Astrophysics Data System (ADS)

The Titan Saturn System Mission (TSSM), another future mission proposed for Titan's exploration, includes an orbiter and two in situ elements: a hot-air balloon and a lake lander. The instrumentation of those two elements will be presented.

Coustenis, A.; Lunine, J.; Reh, K.; Lebreton, J.-P.; Erd, C.; Beauchamp, P.; Matson, D.

2012-10-01

326

Titan's impact history  

NASA Astrophysics Data System (ADS)

Impacts play a major role in the growth and evolution of planets, satellites, and other nameless things. Titan is no exception. This talk will address a subset of the following topics: (i) The modern impact rate is constrained by the population of Centaurs and the impact rate at Jupiter. (ii) Titan's thick atmosphere and volatile surface cause it to respond to major impacts in an Earth-like manner. The impact that made Menrva - the 440 km diameter impact basin sited near the current apex of Titan's motion - was big enough to raise the average global surface temperature above 273 K, which suggests that water rain was possible. This would have been followed by methane drizzles lasting for thousands of years. More modest impacts will generate crater lakes and will saturate the atmosphere with methane, the latter leading to hundreds of years of intermittent drizzle. (iii) Impact ejecta from Menrva will strike Hyperion and should saturate the latter with sesquinary craters. (iv) In any modern story of how Titan got its atmosphere, solar nebular condensates (comets) deliver the volatiles. A consequence of a cometogenic atmosphere is that the atmosphere is heavily processed by strong shocks. The high temperatures produce a wide range of chemical species that would not otherwise be abundant. Some of these will survive to mix into the atmosphere (e.g., CO) or freeze out to fall to the surface (e.g. CO2). (v) That Titan even has an atmosphere, when Callisto and Ganymede do not, is an excellent question. The leading explanation is that Titan alone was made from ammonia - and methane - rich stuff. But the competition between impact delivery and impact expulsion of volatiles can strongly favor Titan over Callisto. Stable isotopes as well as total volatile inventories provide constraints.

Zahnle, Kevin

2010-04-01

327

The commercial Titan launch vehicle  

Microsoft Academic Search

Martin Marietta is making available a commercial version of the Titan launch vehicle. At a total payload weight capability of 31,600 pounds to low earth orbit, the commercial Titan provides Shuttle and Ariane compatible services to the commercial satellite community. This paper describes the commercial Titan which is based on the U.S. Air Force Titan 34D. A large diameter payload

J. Troutman; S. Isakowitz

1987-01-01

328

Barium titanate nanocomposite capacitor FY09 year end report.  

SciTech Connect

This late start RTBF project started the development of barium titanate (BTO)/glass nanocomposite capacitors for future and emerging energy storage applications. The long term goal of this work is to decrease the size, weight, and cost of ceramic capacitors while increasing their reliability. Ceramic-based nanocomposites have the potential to yield materials with enhanced permittivity, breakdown strength (BDS), and reduced strain, which can increase the energy density of capacitors and increase their shot life. Composites of BTO in glass will limit grain growth during device fabrication (preserving nanoparticle grain size and enhanced properties), resulting in devices with improved density, permittivity, BDS, and shot life. BTO will eliminate the issues associated with Pb toxicity and volatility as well as the variation in energy storage vs. temperature of PZT based devices. During the last six months of FY09 this work focused on developing syntheses for BTO nanoparticles and firing profiles for sintering BTO/glass composite capacitors.

Stevens, Tyler E.; DiAntonio, Christopher Brian; Yang, Pin; Chavez, Tom P.; Winter, Michael R.; Monson, Todd C.; Roesler, Alexander William; Fellows, Benjamin D.

2009-11-01

329

The Titan IV launch vehicle  

Microsoft Academic Search

Titan launch vehicles have been contributing to the national space accomplishments for more than 20 years. As the U.S. space program has grown, the Titan family has expanded to meet the changing requirements. The dependability and versatility of Titan vehicles have been demonstrated by their selection for various missions, including strategic intercontinental ballistic missile weapon systems, manned Gemini space flights,

Arthur C. Morrissey; Stephen T. O'Neill

1989-01-01

330

The Titan Graphics Supercomputer Architecture  

Microsoft Academic Search

The design criteria for the Titan are outlined, and the hardware, architecture, and implementation developed to meet them are examined. The key architectural elements in Titan are described, and the reasoning behind their selection is presented. Titan's processor subsystem is explored, focusing on how it reduces the cost and complexity of graphics-specific hardware. The design constraints and implementation of the

Tom Diede; Carl F. Hagenmaier; Glen S. Miranker; Jonathan J. Rubinstein; William S. Worley Jr.

1988-01-01

331

Chemical Reactions During Wet-Etching Process of LSMO\\/PZT\\/LSMO-Structured Device Fabrication  

Microsoft Academic Search

Wet-etching behavior of Lanthanum Strontium Manganate (LSMO) electrode and ferroelectric Pb0.52Zr0.48TiO3 (PZT) for large area thin film using LSMO\\/PZT\\/LSMO micro-sensing device was investigated using various etching solutions. The results show that PZT and LSMO thin films can be protected by the Pt hard etching mask. The etching mechanism of PZT film was attributed to the double replacement reaction etching model.

Tsung-Her Yeh; M. B. Suresh; Jun-Nan Shen; Jyh-Cheng Yu; Chen-Chia Chou

2009-01-01

332

Microstructure and Electrical Properties of the PNN-PZT Thick Films Prepared by Electrophoretic Deposition  

Microsoft Academic Search

PNN-PZT thick films were prepared by electrophoretic deposition method on different substrates, such as Al2O3, PNN-PZT and Pt. The effects of the substrates and sintering temperature on the densification, microstructure, dielectric and ferroelectric properties of the PNN-PZT thick films were investigated. The results show that the density and the dielectric constant of the films deposited on the PNN-PZT ceramic substrates

R. J. Cao; S. C. Zhao; G. R. Li; J. T. Zeng; L. Y. Zheng

2010-01-01

333

Methane ocean on Titan?  

NASA Astrophysics Data System (ADS)

There was an impressive list of names on a recent scientific communication that argues for the existence on Titan of an ocean of liquid methane (CH4) perhaps several hundred meters deep. C. Sagan and S. Dermott with helpful comments by S. Oter, S. Ostro, S. Peale, C. Yoder, W. Thompson, S. Squyres, G. Pettengill, P. Gierasch, and B. Khare speculate that such a methanic ocean, with its Saturnian tides and its tholinian floor, should exist all over Titan's surface; it should unless, they conclude, there is the ‘distracting coincidence [that] … the position of the surface of Titan [is] … near the liquidus in the CH4phase diagram [and, consequently, there is] …almost no methane ocean at all’ (Nature, 300, 731, 1982).We know very little about Titan and its surface; the way of checking into Sagan and Dermott's ideas appears to rest on the interpretation of radar reflectivity data. Preliminary attempts to obtain radar data were made in 1979 with the 305-m Arecibo telescope, but only broad limits resulted. The next opportunity for a measurement at Arecibo comes in the 1990's. Of course, the ideal circumstance would be to send spacecraft equipped with a radar reflectometer for a Titan flyby.

Bell, Peter M.

334

Early History of Titan  

NASA Astrophysics Data System (ADS)

We revisit models for the early history of Titan. Our models start a few My after the production of calcium- aluminum inclusions (CAIs), consistent with the dates required by our thermophysical-dynamical modeling of Saturn's medium-sized satellites. Depending on the time of formation with respect to CAIs, the accretion time scale, and the available accretional energy, models of Titan's interior after accretion are partially to fully differentiated. At one extreme of the models, Titan accretes incorporating a minimal amount of heat. This results in a relatively cold core that, over the long term, heats up and overturns, consistent with previous models of Titan. At the other extreme, accretional heat and heat fom the decay of short-lived radiogenic isotopes results in quick and complete differentiation. In this model there is no core overturn, and conditions soon develop for silicate serpentinization, and hydrothermal activity starts. We identify the periods during which conditions are suitable for hydrothermal geochemistry leading to the production of molecular nitrogen from ammonia decomposition and methane from the Fischer-Tropsch reaction. Key questions include the availability of suitable metal catalysts and/or clay minerals, storage of the reactants and products in the interior of Titan, and mechanisms by which they are released to the atmosphere. Acknowledgements: This work was carried out at the Jet Propulsion Laboratory-California Institute of Technology, under contract to NASA.

Castillo-Rogez, J. C.; Matson, D. L.; Johnson, T. V.; Atreya, S.; Lunine, J. I.

2007-05-01

335

Lattice dynamics and ferroelectric instability of PZT from first principles  

NASA Astrophysics Data System (ADS)

The lattice dynamics of the prototypical cubic perovskite structure has long been considered central to the understanding of the ferroelectric and piezoelectric behavior of perovskite oxides. In solid solutions such as PZT, compositional disorder greatly complicates the theoretical study of the lattice dynamics. The virtual crystal approximation (VCA) is an easily implemented approach to the calculation of interatomic force constants (IFC) in solid solutions; however, as shown by comparison with full ab-initio calculations for ordered alloy configurations, it provides a poor description of the lattice dynamics of PZT. An alternative ab-initio based approach, proposed in [1], is to transfer the IFC's computed for the endpoint compounds to the solid solution. We will present results of the application of this approach to PZT and discuss the implications for effective Hamiltonian simulations of finite-temperature behavior. 1. Ph. Ghosez, E. Cockayne, U. V. Waghmare and K. M. Rabe, Phys. Rev. B60, 836 (1999).

Bungaro, Claudia; Rabe, Karin M.

2001-03-01

336

Measurement of driving electrical signal and input impedance analysis of PZT transducer in thermosonic bonding  

Microsoft Academic Search

In thermosonic bonding process, the driving electrical signal and input impedance of PZT transducer reflect directly the bonding process between gold ball and substrate. This paper describes a method of getting the electrical signal of PZT transducer during the thermosonic bonding process, and analyzes the input impedance of PZT transducer based on the sampled data. From many experiment samples we

Long Zhili; Wu Yunxin; Han Lei; Li Jianping; Zhou Hongquan

2004-01-01

337

Piezoelectrically pushed rotational micromirrors using detached PZT actuators for wide-angle optical switch applications  

Microsoft Academic Search

This paper presents a torsional micromirror detached from PZT actuators (TMD), whose rotational motion is achieved by push bars in the PZT actuators, detached from the micromirror. The push bar mechanism is intended to reduce the bending, tensile and torsional constraints generated by the conventional bending bar mechanism, where the torsional micromirror is attached to the PZT actuators (TMA). We

Sung-Jin Kim; Young-Ho Cho; Hyo-Jin Nam; Jong Uk Bu

2008-01-01

338

On the Closed Loop Control of a PZT to Stabilise a Mach-Zehnder Interferometer  

Microsoft Academic Search

When stabilising a fiber optic Mach-Zehnder interferometer using a PZT, the maximum possible closed-loop bandwidth is limited by the resonance frequency of the PZT. A PZT control circuit using a current source drive is proposed that gives an improved control bandwidth when compared with a voltage source drive. Equations are given to select the parameters of the system to get

S. Dilwali; G. Soundra Pandian

1992-01-01

339

Research on the excitation modes of PZT element in bending cylindrical transducers  

Microsoft Academic Search

The PZT element acts as a core component which transforms the input electric energy to output mechanical energy in ultrasonic transducer. So the excitation modes of PZT element have an important influence on the characteristics of transducer. The force factor formulas of cylindrical transducers based on the bending vibration mode are deduced in theory and the excitation modes of PZT

Ting-hai Cheng; Xiang-dong Guo; Gang Bao

2011-01-01

340

The observational program and research tests of an automatic PZT with prolonged exposure  

Microsoft Academic Search

The theory and instrumentation of the PZT have been described by several authors. In comparison to other techniques available for the determination of Earth Rotation Parameters (ERP), the PZT has many advantages. Among these are its rigid construction, elimination of levelling errors, minimization of refraction errors, ease of operation, etc. Among the disadvantages of a PZT are its limited field

Buxi Gao; Jinfeng Li

1991-01-01

341

Topological Modeling of Metamict Zircon  

NASA Astrophysics Data System (ADS)

Zircon (ZrSiO4) is the most studied metamict mineral and a leading model for candidate ceramic hosts designed to encapsulate highly radioactive nuclear waste and excess plutonium. It is also emblematic of compound oxide ceramics with a potential to phase separate in the amorphized state. Several groups have carried out ab initio or molecular dynamics (MD) simulations of melt-quenched or radiation-disordered zircon. A tendency for silica tetrahedra to polymerize, implying incipient phase separation, has been noted, but adequate descriptors of the amorphous state capable of distinguishing between different disordered arrangements have not been available. This contribution details critical modifications made to empirical potentials used in MD simulations and useful improvements in modeling efficiency that have facilitated constant pressure simulations of quenched and displacement cascade-amorphized zircon. The simulated end- states have been subjected to topological assessment algorithms for enumerating coordinations, bond lengths and bond angles; counting primitive rings and identifying structure-defining local primitive-ring clusters; and assessing degree of coordination-unit polymerization. The topologies of simulated melt, melt-quenched and cascade-amorphized disordered arrangements have been found to be different and distinguishable. A two-body Born-Mayer empirical potential with ZBL short-range repulsive term was fit to major structural, elastic, thermal and dielectric properties of crystalline zircon, but it was noted that the best crystalline fit, with non-stoichiometric partial ion charges, led to unrealistic coordinations in amorphized arrangements and uncontrolled expansions in constant pressure simulations because of silica polymerization. Therefore, stoichiometrically charge-balanced partial charges were instead chosen and optimized; the optimal choice of O-1.2, Si+2.4, Zr+2.4 led to realistic coordinations (Zr 7, Si 4) and well-behaved constant-pressure simulations of amorphous zircon that notably differed from constant volume simulations using unbalanced changes and imposed volume swellings. Compact cascade simulations (up to 14,112 atoms) were made possible by using heat removal at simulation cell periodic boundaries and simulation cell shape optimized to cascade geometry for Zr and U primary-knock-on atom (PKA) with energies 1-10 keV (collisional). Ring count distributions and primitive ring size averages for Zr and Si local clusters proved different and distinguishable for melt (Zr 11.57, Si 11.47), quenched (Zr 9.81, Si 9.80) and cascade-amorphized (Zr 9.74, Si 9.36) structures, and larger than for crystalline zircon (Zr 7.66, Si 7.76). Topological signatures, devised to distinguish locally-crystalline from locally-amorphized zircon, established unambiguously that zircon amorphized within the first PKA cascade. Sub-cascades were observed for 10-keV Zr, but not U PKAs. In quenched zircon, 93% of Si atoms were connected to another Si atom through bridging O atoms (i.e. polymerized), with the average number Q of bridging O per Si found to be 1.95.

Hobbs, L. W.; Zhang, Y.; Yuan, X.

2006-05-01

342

Diurnal variations of Titan  

NASA Astrophysics Data System (ADS)

We present our analysis of the diurnal variations of Titan's ionosphere (between 1,000 and 1,400 km) based on a sample of Ion Neutral Mass Spectrometer (INMS) measurements in the Open Source Ion (OSI) mode obtained from 8 close encounters of the Cassini spacecraft with Titan. Though there is an overall ion depletion well beyond the terminator, the ion content on Titan's nightside is still appreciable, with a density plateau of ~700 cm-3 below ~1,300 km. Such a plateau is associated with the combination of distinct diurnal variations of light and heavy ions. Light ions (e.g. CH5+, HCNH+, C2H5+) show strong diurnal variation, with clear bite-outs in their nightside distributions. In contrast, heavy ions (e.g. c-C3H3+, C2H3CNH+, C6H7+) present modest diurnal variation, with significant densities observed on the nightside. We propose that the distinctions between light and heavy ions are associated with their different chemical loss pathways, with the former primarily through "fast" ion-neutral chemistry and the latter through "slow" electron dissociative recombination. The INMS data suggest day-to-night transport as an important source of ions on Titan's nightside, to be distinguished from the conventional scenario of auroral ionization by magnetospheric particles as the only ionizing source on the nightside. This is supported by the strong correlation between the observed night-to-day ion density ratios and the associated ion lifetimes. We construct a time-dependent ion chemistry model to investigate the effects of day-to-night transport on the ionospheric structures of Titan. The predicted diurnal variation has similar general characteristics to those observed, with some apparent discrepancies which could be reconciled by imposing fast horizontal thermal winds in Titan's upper atmosphere.

Cui, J.; Galand, M.; Yelle, R. V.; Vuitton, V.; Wahlund, J.-E.; Lavvas, P. P.; Mueller-Wodarg, I. C. F.; Kasprzak, W. T.; Waite, J. H.

2009-04-01

343

Zircon Saturation Re-Revisited  

NASA Astrophysics Data System (ADS)

Zircon saturation in silicate melts has been utilized for magma thermometry and predicting the survival of zircon xenocrysts in crustal melts for nearly 30 years. The original calibration, which assumed only compositional (M = [2Ca+Na+K]/[AlxSi]) and temperature controls, was bolstered by subsequent experimental investigations and thermometry of volcanic rocks and glasses. These latter studies, while confirming the general predictions of the model, suggested that other environmental parameters (e.g., pressure, H 2O, halogens, [Fe], oxygen fugacity, etc.) might have second-order effects. Given the tremendous advances in micro-analytical capabilities over the intervening three decades, we have returned to this question with a view to obtaining a refined zircon solubility calibration as a function of P, T, [H2O] and FM (= [Na+K+2(Ca+Mg+Fe)]/[AlxSi]). Detailed SEM imaging of the original low-temperature crystallization experiments (1.2-2.1 kbar) revealed limitations of this approach and we chose instead to use a new experimental design in which shattered Mud Tank zircon is infiltrated by melts of selected composition and water contents. 10 kbar hydrothermal experiments (925o and 850oC) were run for sufficiently long durations (2 to 3 days) to ensure microscale diffusive equilibration of Zr released by zircon dissolution into the intercrystalline melt pools. Sectioned run products were analyzed by SIMS ion imaging of selected areas where glass is exposed in close proximity to or surrounded by Mud Tank zircon fragments. Ion imaging has the advantage of permitting high spatial resolution (3 ?m) analysis of the glasses allowing assessment of Zr equilibration. Using synthetic glass standards, we found [Zr] in anhydrous glasses to be enhanced by ca. 20% relative to hydrous (at 6 wt.% H2O). Our new experiments and re-analysis of the earlier glasses broadly reproduce the original calibration, albeit with substantially enhanced (factor of five) precision compared to the original EMPA analyses. Thus it appears that no significant pressure effect exists up to at least 10 kbar. Ongoing work will expand the pressure range beyond this limit and explore a greater compositional space than previously constrained.

Boehnke, P.; Trail, D.; Schmitt, A. K.; Watson, E. B.; Harrison, M.

2011-12-01

344

Aboard the Titanic  

NSDL National Science Digital Library

You will be exploring the R.M.S Titanic. This includes an individual passenger, the class system on board, the collision and warnings leading up to it, and the construction of the ship. Introduction: You are going to be a passenger on board the RMS Titanic. You boarded the ship and set sail expecting the experience of a lifetime upon the Ship of Dreams, but what will happen next? In this project we will be exploring how the ship was structured, what activities were ...

Maahs, Mrs.

2010-04-20

345

Manufacture and characterization of high activity piezoelectric fibres  

NASA Astrophysics Data System (ADS)

Piezoelectric fibres are finding increasing application in a variety of piezoelectric composites, including active fibre composites (AFCs). This paper describes the manufacture and characterization of lead zirconate titanate (PZT) fibres manufactured by viscous plastic processing (VPP). The manufacturing method will be described along with a systematic characterization of the macrostructure, microstructure, phase composition and low and high field piezoelectric properties. A comparison with other available PZT fibres will be made, which demonstrates that the VPP PZT fibres display high piezoelectric coefficients.

Bowen, C. R.; Stevens, R.; Nelson, L. J.; Dent, A. C.; Dolman, G.; Su, B.; Button, T. W.; Cain, M. G.; Stewart, M.

2006-04-01

346

A novel multi-degree-of-freedom thick-film ultrasonic motor  

Microsoft Academic Search

This paper describes a new multi-degree-of-freedom (MDOF) ultrasonic motor that comprises few parts and is based on low-cost thick-film technology. Conventional ultrasonic motors using bulk lead zirconate titanate (PZT) or thin-film PZT layers are relatively expensive at the present time. Thick-film printed PZT technology provides the opportunity to reduce the costs of ultrasonic motors. To demonstrate the feasibility of this

Manaba Aoyagi; S. P. Beeby; N. M. White

2002-01-01

347

Thickness effect on electrical properties of Pb(Zr 0.52Ti 0.48)O 3 thick films embedded with ZnO nanowhiskers prepared by a hybrid sol–gel route  

Microsoft Academic Search

Silicon-based lead zirconate titanate thick films embedded with zinc oxide nanowhiskers (ZnOw–PZT) were prepared by a hybrid sol–gel route. ZnOw–PZT films with thickness from 1.5?m to 4?m are perovskite structure and have smooth surface without any cracks. As the thickness increases, the remanent polarization and dielectric constant increase, but the coercive field and tetragonality decrease. Compared with PZT films, the

Q. L. Zhao; M. S. Cao; J. Yuan; R. Lu; D. W. Wang; D. Q. Zhang

2010-01-01

348

Flexible ultrasonic transducers for structural health monitoring of metals and composites  

Microsoft Academic Search

Flexible ultrasonic transducers (FUTs) which have the on-site installation capability are presented for the non-destructive evaluation (NDE) and structural health monitoring (SHM) purposes. These FUTs consist of 75 mum thick titanium membrane, thick (> 70 mum) thick piezoelectric lead-zirconate-titanate (PZT) composite (PZT-c) films and thin (< 5 mum) thick top electrodes. The PZT-c films are made by a sol-gel spray

M. Kobayashi; K.-T. Wu; J.-L. Shih; C.-K. Jen; S. E. Kruger

2010-01-01

349

Inelastic neutron scattering from zircon  

SciTech Connect

A lattice dynamical investigation of zircon (ZrSiO{sub 4}) has been carried out to obtain a microscopic understanding of its thermodynamic properties, as well as to examine possible soft modes that may contribute to the phase transformation to scheelite type under high pressure. We have measured the neutron weighted phonon density of states of zircon from a polycrystalline sample. The neutron spectra reveal one-phonon excitations extending to 1130 cm{sup -1}, with phonon bands centered at 226, 298, 363, 540, 661, 726, 945, and 1081 cm{sup -1}. A quantitative analysis of the neutron results was carried out using a lattice dynamical rigid-ion model. 4 refs., 3 figs.

Nipko, J.C.; Loong, C.K.

1997-07-14

350

Trace element chemistry of zircons from oceanic crust: A method for distinguishing detrital zircon provenance  

USGS Publications Warehouse

We present newly acquired trace element compositions for more than 300 zircon grains in 36 gabbros formed at the slow-spreading Mid-Atlantic and Southwest Indian Ridges. Rare earth element patterns for zircon from modern oceanic crust completely overlap with those for zircon crystallized in continental granitoids. However, plots of U versus Yb and U/Yb versus Hf or Y discriminate zircons crystallized in oceanic crust from continental zircon, and provide a relatively robust method for distinguishing zircons from these environments. Approximately 80% of the modern ocean crust zircons are distinct from the field defined by more than 1700 continental zircons from Archean and Phanerozoic samples. These discrimination diagrams provide a new tool for fingerprinting ocean crust zircons derived from reservoirs like that of modern mid-ocean ridge basalt (MORB) in both modern and ancient detrital zircon populations. Hadean detrital zircons previously reported from the Acasta Gneiss, Canada, and the Narryer Gneiss terrane, Western Australia, plot in the continental granitoid field, supporting hypotheses that at least some Hadean detrital zircons crystallized in continental crust forming magmas and not from a reservoir like modern MORB. ?? 2007 The Geological Society of America.

Grimes, C. B.; John, B. E.; Kelemen, P. B.; Mazdab, F. K.; Wooden, J. L.; Cheadle, M. J.; Hanghoj, K.; Schwartz, J. J.

2007-01-01

351

Matrix cracking and creep behavior of monolithic zircon and zircon silicon carbide fiber composites  

Microsoft Academic Search

In this study, the first matrix cracking behavior and creep behavior of zircon matrix silicon carbide fiber composites were studied, together with the fracture and creep behavior of the monolithic zircon. These behaviors are of engineering and scientific importance, and the study was aimed at understanding the deformation mechanisms at elevated temperatures. The first matrix cracking behavior of zircon matrix

Umashankar Anandakumar

2000-01-01

352

Ceramic–electrode interaction in PZT and PNN–PZT multilayer piezoelectric ceramics with AG\\/PD 70\\/30 inner electrode  

Microsoft Academic Search

Pb(Zr0.53Ti0.47)O3(PZT) and PbNi1\\/3Nb2\\/3O3-PZT (PNN–PZT) multilayers with Ag\\/Pd 70\\/30 inner electrodes have been studied from the point of view of the ceramic–electrode interaction. PZT multilayers have shown silver free ceramic layers, and no lead has been detected in the electrode after sintering. Silver transport through the ceramic is avoided because of low open porosity–close porosity transition temperature. This transition seems to

A. C Caballero; E Nieto; P Duran; C Moure; M Kosec; Z Samardzija; G Drazic

1997-01-01

353

Electrical power generation characteristics of PZT piezoelectric ceramics  

Microsoft Academic Search

The electrical power generation characteristics of Mn-doped PZT ceramics responding to slow mechanical stress as well as to impact stress have been investigated. Although both the slow and impact stresses induce a reversible electrical response, the generation properties are distinctly different. Slow stress releases two output current peaks with opposite directions, responding to the increasing and decreasing part of the

Chao-Nan Xu; Morito Akiyama; Kazuhiro Nonaka; Tadahiko Watanabe

1998-01-01

354

Processing of PZT piezoelectric thin films for microelectromechanical systems  

Microsoft Academic Search

Piezoelectric Pb(Zr0.52Ti0.48)O3 (PZT) thin films for microelectromechanical systems (MEMS) were deposited on platinum coated silicon substrates by sol-gel processing using lead acetate trihydrate as the lead source. A thickness uniformity of better than 1% variation over 4\\

Mary Hendrickson; Tao Su; Susan Trolier-McKinstry; Bernard J. Rod; Robert J. Zeto

1996-01-01

355

Torsional actuator motor using solid freeform fabricated PZT ceramics  

NASA Astrophysics Data System (ADS)

A torsional actuator has been developed at NRL utilizing the high piezoelectric shear coefficient, d15. This torsional actuator uses an even number of alternately poled segments of electroactive PZT. Under an applied electric field, the torsional actuator produces large angular displacement and a high torque. The solid freeform fabrication technique of the laminated object manufacturing (LOM) is used for rapid prototyping of torsional actuator with potential cost and time saving. First step to demonstrate the feasibility of the LOM technique for the torsional actuator device fabrication is to make near net shape segments. We report a prototype PZT torsional actuator using LOM prepared PZT-5A segments. Fabrication processes and test results are described. The torsional actuator PZT-5A tube has dimensions of 13 cm long, 2.54 cm OD and 1.9 cm ID. Although the piezoelectric strain is small, it may be converted into large displacement via accumulation of the small single cycle displacements over many cycles using AC driving voltage such as with a rotary 'inchworm' actuator or an ultrasonic rotary motor. A working prototype of a full-cycle motor driven by the piezoelectric torsional actuator has been achieved. The rotational speed is 1,200 rpm under 200 V/cm field at the resonant frequency of 4.5 kHz.

Kim, Chulho; Wu, Carl C. M.; Bender, Barry

2004-07-01

356

Tape Casting of Honeywell PZT Type III Powder.  

National Technical Information Service (NTIS)

This is the fourth and final report in the series dealing with transfer of tape casting technology from The Pennsylvania State University, Materials Research Laboratory to Honeywell Ceramic Center. The report deals with characterization of H.C.C. PZT powd...

J. V. Biggers G. O. Dayton B. A. Jones

1984-01-01

357

The Exploration of Titan  

Microsoft Academic Search

he exploration of Saturn's moon Titan is reviewed, noting the dramatic recent improvements in our knowledge of this strange world from the ongoing inter- national Cassini-Huygens mission, results from which are summarized. Among Cassini's discoveries are the remarkable richness and complexity of its organic chemistry, a strikingly Earth-like landscape with hydrocarbon lakes and seas, and vast fields of organic sand

Ralph D. Lorenz

358

Titan: An exogenic world?  

Microsoft Academic Search

All landforms on Titan that are unambiguously identifiable can be explained by exogenic processes (aeolian, fluvial, impact cratering, and mass wasting). Previous suggestions of endogenically produced cryovolcanic constructs and flows have, without exception, lacked conclusive diagnostic evidence. The modification of sparse recognizable impact craters (themselves exogenic) can be explained by aeolian and fluvial erosion. Tectonic activity could be driven by

Jeffrey M. Moore; Robert T. Pappalardo

2011-01-01

359

Semiconducting barium titanate  

Microsoft Academic Search

Barium titanate, which is well known as a basic ferroelectric material, is also of interest when doped because of the interaction between semiconductivity and ferroelectricity. The resistance of blocking layers at surfaces and grain-boundaries is governed mainly by the ferroelectric properties, so that a resistance jump of four decades is observed on heating above the Curie temperature. A survey of

W. Heywang

1971-01-01

360

The atmosphere of Titan.  

PubMed

The discovery that Titan had an atmosphere was made by the identification of methane in the satellite's spectrum in 1944. But the abundance of this gas and the identification of other major constituents required the 1980 encounter by the Voyager 1 spacecraft. in the intervening years, traces of C2H2, C2H4, C2H6 and CH3D had been posited to interpret emission bands in Titan's IR spectrum. The Voyager infrared Spectrometer confirmed that these gases were present and added seven more. The atmosphere is now known to be composed primarily of molecular nitrogen. But the derived mean molecular weight suggests the presence of a significant amount of some heavier gas, most probably argon. It is shown that this argon must be primordial, and that one can understand the evolution of Titan's atmosphere in terms of degassing of a mixed hydrate dominated by CH4, N2 and 36Ar. This model satisfactorily explains the absence of neon and makes no special requirements on the satellite's surface temperature. The organic chemistry taking place on Titan today invites comparison with chemical evolution on the primitive Earth prior to the origin of life. PMID:7097773

Owen, T

1982-01-01

361

Future Titan Mission Studies  

NASA Astrophysics Data System (ADS)

Exploration of Titan will remain a solar system science priority even (or especially) after Cassini. Not only does Titan offer an array of meteorological, oceanographical and geological phenomena richer than anywhere except Earth, but Titan's importance as an astrobiological target with a rich organic inventory has been long recognized. In-situ surface chemistry studies, meteorological and seismological monitoring and high-resolution geomorphological investigations are beyond Cassini's capabilities. Concepts for future missions involve a mobile airborne platform able to access sur- face materials at a number of locations, and an orbiter for communications support and survey observations. Detailed studies at JPL have evaluated mission options in- cluding a lander or a blimp (airship) supported by an orbiter, with launch in the 2010- 2015 timeframe, allowing early Cassini results to refine the mission science goals and implementation strategies. After a 10 year cruise and aerocapture, the mission would provide an enormous bounty of data from a 1-3 year tour of Titan. International col- laboration would broaden the scope of the mission and would build on the successful Cassini-Huygens experience.

Kakuda, R.; Spilker, T.; Baines, K.; Lorenz, R.

362

Titan Nitriles Awaiting Detection  

NASA Astrophysics Data System (ADS)

The nitrogen-methane haze of Titan is known to harbor at least four molecules containing a nitrile (-CN) group: H-CN, NC-CN, CH3-CN, and HCC-CN. The low-temperature reaction chemistry of these molecules is of interest as the Cassini orbiter and Huygens probe approach the Saturnian system. As part of our preparation for Cassini-Huygens results we have undertaken an experimental study of the dominant chemical changes of nitrile molecules. Our results point to isomerization products formed by both low-temperature photochemistry and radiation chemistry. Among the new molecules we can predict are isonitriles (e.g. CH3-NC) and enimines (e.g. H2C=C=NH). We also expect, depending on the amount of H2O present, that cyanate ions (OCN-) can form on Titan. This presentation will include our latest results for Titan nitriles, as well a few nitriles not yet detected on Titan but present in either cometary comae or the interstellar medium. Since nitriles can form biological molecules, such as alpha-amino acids, purines, and pyrimidines, our results may also have astrobiological implications. -- The authors acknowledge NASA funding through the SARA and Planetary Atmospheres programs. RLH acknowledges support from NASA grant NAG-5-1843.

Hudson, R. L.; Moore, M. H.

2003-05-01

363

Exobiology on Titan  

Microsoft Academic Search

With a dense N2-CH4 atmosphere rich in organics, both in gas and aerosol phases, and with the possible presence of hydrocarbons oceans on its surface, Titan, the largest satellite of Saturn, appears as a natural laboratory to study chemical evolution toward complex organic systems, in a planetary environment and over a long time scale. Thanks to many analogies with planet

F. Raulin; P. Bruston; P. Coll; D. Coscia; M. C. Gazeau; L. Guez; E. Vanssay

1995-01-01

364

The lakes of Titan  

Microsoft Academic Search

The surface of Saturn's haze-shrouded moon Titan has long been proposed to have oceans or lakes, on the basis of the stability of liquid methane at the surface. Initial visible and radar imaging failed to find any evidence of an ocean, although abundant evidence was found that flowing liquids have existed on the surface. Here we provide definitive evidence for

E. R. Stofan; C. Elachi; J. I. Lunine; R. D. Lorenz; B. Stiles; K. L. Mitchell; S. Ostro; L. Soderblom; C. Wood; H. Zebker; S. Wall; M. Janssen; R. Kirk; R. Lopes; F. Paganelli; J. Radebaugh; L. Wye; Y. Anderson; M. Allison; R. Boehmer; P. Callahan; P. Encrenaz; E. Flamini; G. Francescetti; Y. Gim; S. Hensley; W. T. K. Johnson; K. Kelleher; D. Muhleman; P. Paillou; G. Picardi; F. Posa; L. Roth; R. Seu; S. Shaffer; S. Vetrella

2007-01-01

365

Methane rain on Titan  

Microsoft Academic Search

The atmosphere of Titan is characterized by means of model computations based on Voyager IRIS IR spectra and published data from laboratory determinations of absorption coefficients and cloud refractive indices. The results are presented in tables and graphs, and it is pointed out that the presence of Ar is not required in the model. Particular attention is given to the

O. B. Toon; C. P. Mckay; R. Courtin; T. P. Ackerman

1988-01-01

366

Radiation damage effects in zircon  

NASA Astrophysics Data System (ADS)

Zircon, ZrSiO_4, is important for geology and geochronology, and has been proposed as a host material to immobilize highly radioactive materials from dismantled weapons and nuclear waste from power stations [1]. In these applications zircon is exposed to alpha-irradiation. Computer simulations have started to be employed to simulate radiation damage in zircon [2], but the origin and microscopic mechanisms of the most important structural changes in zircon - unit cell expansion and large macroscopic swelling at higher doses, strong shear deformation of the crystalline lattice, and polymerization of SiOn units [3], remain unknown. Here, we perform the molecular dynamics simulation of highly energetic recoils in zircon. Basing on the simulation results, we propose the simple picture of the density change in the damaged region that consists of the depleted and densified matter. We find that the experimentally observed structural changes originate from the interaction of the damaged region with the surrounding crystalline lattice: the shear of the lattice around the damaged region causes shear deformation and expansion of the unit cells. The polymers of connected SiOn polyhedra are most commonly present in the densified shell at the periphery of the damaged region. [1] R C Ewing et al, J. Mater. Res. 10, 243 (1995); W J Weber et al, B E Burakov et al, in Scientific Basis for Nuclear Waste Management XIX, 25-32 and 33-40 (Plenum, New York, 1996); R C Ewing, et al in Crystalline Ceramics: Waste Forms for the Disposal of Weapons Plutonium, NATO Workshop Proceedings 65 (Academic Publishers, Dordrecht, The Netherlands, 1996). [2] B Park et al, Phys. Rev. B, 64, 174108 (1-16) (2001); J P Crocombette and D Ghaleb, J. Nucl. Mater., 295, 167 (2001); K Trachenko et al, J. Appl. Phys., 87, 7702 (2000); K Trachenko et al, J. Phys.: Cond. Matt., 13, 1947 (2001). [3] T Murakami et al, Am. Min., 76, 1510 (1991); H D Holland and D Gottfried, Acta Cryst. 8, 291 (1955).; W J Weber, J. Am. Ceram. Soc., 76, 1729 (1993); W J Weber et al, J. Mater. Res. 9, 688 (1994); S Rios and E K H Salje, J.Phys.: Condens. Matter 11, 8947 (1999); I Farnan, Phase Trans. 69, 47 (1999); I Farnan and E K H Salje, J. Appl. Phys. 89, 2084 (2001).

Trachenko, Kostya; Dove, Martin; Salje, Ekhard

2002-03-01

367

Titanic Weather Forecasting  

NASA Astrophysics Data System (ADS)

New Detailed VLT Images of Saturn's Largest Moon Optimizing space missions Titan, the largest moon of Saturn was discovered by Dutch astronomer Christian Huygens in 1655 and certainly deserves its name. With a diameter of no less than 5,150 km, it is larger than Mercury and twice as large as Pluto. It is unique in having a hazy atmosphere of nitrogen, methane and oily hydrocarbons. Although it was explored in some detail by the NASA Voyager missions, many aspects of the atmosphere and surface still remain unknown. Thus, the existence of seasonal or diurnal phenomena, the presence of clouds, the surface composition and topography are still under debate. There have even been speculations that some kind of primitive life (now possibly extinct) may be found on Titan. Titan is the main target of the NASA/ESA Cassini/Huygens mission, launched in 1997 and scheduled to arrive at Saturn on July 1, 2004. The ESA Huygens probe is designed to enter the atmosphere of Titan, and to descend by parachute to the surface. Ground-based observations are essential to optimize the return of this space mission, because they will complement the information gained from space and add confidence to the interpretation of the data. Hence, the advent of the adaptive optics system NAOS-CONICA (NACO) [1] in combination with ESO's Very Large Telescope (VLT) at the Paranal Observatory in Chile now offers a unique opportunity to study the resolved disc of Titan with high sensitivity and increased spatial resolution. Adaptive Optics (AO) systems work by means of a computer-controlled deformable mirror that counteracts the image distortion induced by atmospheric turbulence. It is based on real-time optical corrections computed from image data obtained by a special camera at very high speed, many hundreds of times each second (see e.g. ESO Press Release 25/01 , ESO PR Photos 04a-c/02, ESO PR Photos 19a-c/02, ESO PR Photos 21a-c/02, ESO Press Release 17/02, and ESO Press Release 26/03 for earlier NACO images, and ESO Press Release 11/03 for MACAO-VLTI results.) The southern smile ESO PR Photo 08a/04 ESO PR Photo 08a/04 Images of Titan on November 20, 25 and 26, 2002 Through Five Filters (VLT YEPUN + NACO) [Preview - JPEG: 522 x 400 pix - 40k] [Normal - JPEG: 1043 x 800 pix - 340k] [Hires - JPEG: 2875 x 2205 pix - 1.2M] Caption: ESO PR Photo 08a/04 shows Titan (apparent visual magnitude 8.05, apparent diameter 0.87 arcsec) as observed with the NAOS/CONICA instrument at VLT Yepun (Paranal Observatory, Chile) on November 20, 25 and 26, 2003, between 6.00 UT and 9.00 UT. The median seeing values were 1.1 arcsec and 1.5 arcsec respectively for the 20th and 25th. Deconvoluted ("sharpened") images of Titan are shown through 5 different narrow-band filters - they allow to probe in some detail structures at different altitudes and on the surface. Depending on the filter, the integration time varies from 10 to 100 seconds. While Titan shows its leading hemisphere (i.e. the one observed when Titan moves towards us) on Nov. 20, the trailing side (i.e the one we see when Titan moves away from us in its course around Saturn) - which displays less bright surface features - is observed on the last two dates. ESO PR Photo 08b/04 ESO PR Photo 08b/04 Titan Observed Through Nine Different Filters on November 26, 2002 [Preview - JPEG: 480 x 400 pix - 36k] [Normal - JPEG: 960 x 800 pix - 284k] Caption: ESO PR Photo 08b/04: Images of Titan taken on November 26, 2002 through nine different filters to probe different altitudes, ranging from the stratosphere to the surface. On this night, a stable "seeing" (image quality before adaptive optics correction) of 0.9 arcsec allowed the astronomers to attain the diffraction limit of the telescope (0.032 arcsec resolution). Due to these good observing conditions, Titan's trailing hemisphere was observed with contrasts of about 40%, allowing the detection of several bright features on this surface region, once thought to be quite dark and featureless. ESO PR Photo 08c/04 ESO PR Photo 08c/04 Titan Surface Projections [Previ

2004-04-01

368

Titan Mare Explorer (TiME): A Discovery Mission to Titan’s Hydrocarbon Lakes  

NASA Astrophysics Data System (ADS)

The discovery of lakes in Titan’s high latitudes confirmed the expectation that liquid hydrocarbons exist on the surface of the haze-shrouded moon. The lakes fill through drainage of subsurface runoff and/or intersection with the subsurface alkanofer, providing the first evidence for an active condensable-liquid hydrological cycle on another planetary body. The unique nature of Titan’s methane cycle, along with the prebiotic chemistry and implications for habitability of Titan’s lakes, make the lakes of the highest scientific priority for in situ investigation. The Titan Mare Explorer mission is an ASRG (Advanced Stirling Radioisotope Generator)-powered mission to a lake on Titan. The mission would be the first exploration of a planetary sea beyond Earth, would demonstrate the ASRG both in deep space and a non-terrestrial atmosphere environment, and pioneer low-cost outer planet missions. The scientific objectives of the mission are to: determine the chemistry of a Titan lake to constrain Titan’s methane cycle; determine the depth of a Titan lake; characterize physical properties of liquids; determine how the local meteorology over the lakes ties to the global cycling of methane; and analyze the morphology of lake surfaces, and if possible, shorelines, in order to constrain the kinetics of liquids and better understand the origin and evolution of Titan lakes. The focused scientific goals, combined with the new ASRG technology and the unique mission design, allows for a new class of mission at much lower cost than previous outer planet exploration has required.

Lorenz, R. D.; Stofan, E. R.; Lunine, J. I.; Kirk, R. L.; Mahaffy, P. R.; Bierhaus, B.; Aharonson, O.; Clark, B. C.; Kantsiper, B.; Ravine, M. A.; Waite, J. H.; Harri, A.; Griffith, C. A.; Trainer, M. G.

2009-12-01

369

Quantitative comparison between the degree of domain orientation and nonlinear properties of a PZT ceramic during electrical and mechanical loading  

SciTech Connect

The macroscopic electromechanical coupling properties of ferroelectric polycrystals are composed of linear and nonlinear contributions. The nonlinear contribution is typically associated with the extrinsic effects related to the creation and motion of domain walls. To quantitatively compare the macroscopic nonlinear properties of a lead zirconate titanate ceramic and the degree of domain orientation, in-situ neutron and high-energy x-ray diffraction experiments are performed and they provide the domain orientation density as a function of the external electric field and mechanical compression. Furthermore, the macroscopic strain under the application of external electrical and mechanical loads is measured and the nonlinear strain is calculated by means of the linear intrinsic piezoelectric effect and the linear intrinsic elasticity. The domain orientation density and the nonlinear strain show the same dependence on the external load. The scaling factor that relates to the two values is constant and is the same for both electrical and mechanical loadings.

Marsilius, Mie; Granzow, Torsten; Jones, Jacob L. (Florida); (Darmstadt)

2011-10-26

370

Enhance of ferroelectric properties by modifying Pb2+ side by Mg2+ in PZT (52/48) ceramics  

NASA Astrophysics Data System (ADS)

Magnesium substituted lead zirconate titanate Pb1-xMgxZr0.52Ti0.48O3 (x=0.02, 0.04, 0.06 & 0.08) have been prepared by the sol-gel method. The crystal structure and phase purity of the samples were studied by powder X-ray diffraction (XRD) technique. The ferroelectric hysteresis loop measurements were carried out at room temperature using ferroelectric loop tracer over a field range of 4.5kv/cm. The saturation polarization and coercivety and remnant polarization increase with the increase in magnesium concentration. The piezoelectric constant was measured by varying the polling field was found to be decrease with the increase in concentration of magnesium.

Kour, P.; Kumar, Pawan; Kar, Manoranjan; Sinha, S. K.

2013-02-01

371

Properties of Semiconductive Barium Titanates  

Microsoft Academic Search

The resistivity of barium titanate which is usually of the order of 109˜1012 ohm-cm, may be remarkably reduced with suitable control in valency. The valency-controlled barium titanate, whose resistivity is of the order of 10˜104 ohm-cm at room temperature, shows anomalous positive character in the temperature dependency of the resistivity. For example, the resistivity of barium titanate containing 0.1 mol.

Osamu Saburi

1959-01-01

372

Isotopic Composition of Oxygen in Lunar Zircons.  

National Technical Information Service (NTIS)

The recent discovery of heavy oxygen in zircons from the Jack Hills conglomerates Wilde et al., and Mojzsis et al., was interpreted as an indication of presence of liquid water on the surface of Early Earth. The distribution of ages of Jack Hills zircons ...

A. A. Nemchin M. J. Whitehouse R. T. Pidgeon

2005-01-01

373

Titan's methane cycle in the Titan WRF general circulation model  

NASA Astrophysics Data System (ADS)

Observations of methane clouds, surface lakes and precipitation (or evidence of past precipitation) on Titan allow us to assemble information about the seasonal evolution of Titan’s methane cycle, as well as Titan’s lower atmosphere and near-surface environment in general. Using the TitanWRF general circulation model [Newman et al., 2011] we attempt to reproduce some of these observations by simulating Titan’s atmospheric circulation and methane cycle, assuming limited surface methane and using a simple large-scale cloud scheme both with and without latent heating effects included. We have performed both ‘current’ and ‘reversed perihelion’ simulations, i.e. using the current solar forcing (perihelion in southern summer) and its exact opposite (perihelion in northern summer, as occurred at some time in the past), to test the hypothesis that the timing of perihelion explains the asymmetry in surface methane distribution currently observed. We look at the net transport and latitudinal distribution of surface methane as the simulations tend toward steady state after >100 Titan years. Initially, as the equatorial regions lose and the high latitudes gain significant methane each Titan year, our results are highly sensitive to initial conditions. However, as the simulations tend toward steady state and specifically as the tropics dry out, the ‘current’ and ‘reversed perihelion’ results increasingly tend toward ‘mirror images’ of each other. With the decreased significance of tropical moisture sources, the methane balance becomes dominated by pole-to-pole exchange (inter-polar competition for methane) with the simulations tending toward final states with significantly more high latitude surface methane in the hemisphere with the longer, cooler summer (i.e., in the northern hemisphere for current solar forcing, in line with the asymmetry observed). References: Newman, C. E., et al.: "Stratospheric superrotation in the TitanWRF model". Icarus, Vol. 213, pp. 636-654, 2011.

Newman, C. E.; Lian, Y.; Richardson, M. I.; Lee, C.; Toigo, A. D.

2012-04-01

374

Zircon-rutile-ilmenite froth flotation process  

SciTech Connect

This patent describes a method for separating a mixture of minerals comprising at least zircon, ilmenite and rutile. It comprises adding an acid solution to the mixture to acidify to a pH of between about 2.0 and 6.0; adding starch to the mixture to depress the ilmenite and the rutile; adding a source of fluoride ions to the mixture to provide a negative surface charge on the zircon surface to activate the zircon; adding an amine cationic collector to the mixture to float the activated zircon; subjecting the mixture containing the added acid solution, the fluoride ions, the starch and the cationic collector, to froth flotation; and withdrawing a float product comprising the zircon and a sink product comprising the ilmenite and rutile.

Schmidt, R.; Denham, D.L. Jr.

1992-04-21

375

Zircon refractories for glass-melting (review)  

SciTech Connect

The compositions, some of the properties, and the field of application of zircon refractories produced for glass melting in the USSR and abroad are presented. The studies show that the zircon refractories of enhanced purity with a total concentration of coloring impurities of 0.3% are of particular interest in the melting of several grades of special glasses. Data on the glass resitance of zircon refractories to a series of special glasses are presented; the data were obtained using a dynamic method in a comparison with fused quartz. The degree of corrosion was evaluated from the change in the monitored volume of the specimens before and after contact with the glass. It is clear that the corrosion of the zircon refractories both pressed and also obtained by slip casting is significantly less than the corrosion of refractories made from fused quartz. The zircon refractories can reasonably be used for melting a series of glasses with a low concentration of alkalis.

Mel'nikova, I.G.; Nesterova, T.A.; Razdol'skaya, I.V.

1986-03-01

376

Titan's Surface Brightness Temperatures  

NASA Astrophysics Data System (ADS)

Radiance from the surface of Titan can be detected from space through a spectral window of low opacity in the thermal infrared at 19 ?m (530 cm-1). By combining Composite Infrared Spectrometer observations from Cassini's first four years, we have mapped the latitude distribution of zonally averaged surface brightness temperatures. The measurements are corrected for atmospheric opacity as derived from the dependence of radiance on the emission angle. At equatorial latitudes near the Huygens landing site, the surface brightness temperature is found to be 93.7 ± 0.6 K, in excellent agreement with the in situ measurement. Temperature decreases toward the poles, reaching 90.5 ± 0.8 K at 87°N and 91.7 ± 0.7 K at 88°S. The meridional distribution of temperature has a maximum near 10°S, consistent with Titan's late northern winter.

Jennings, D. E.; Flasar, F. M.; Kunde, V. G.; Samuelson, R. E.; Pearl, J. C.; Nixon, C. A.; Carlson, R. C.; Mamoutkine, A. A.; Brasunas, J. C.; Guandique, E.; Achterberg, R. K.; Bjoraker, G. L.; Romani, P. N.; Segura, M. E.; Albright, S. A.; Elliott, M. H.; Tingley, J. S.; Calcutt, S.; Coustenis, A.; Courtin, R.

2009-02-01

377

Titanic exploration with GIS  

USGS Publications Warehouse

To help teachers and students investigate one of the world's most famous historical events using the geographic perspective and GIS tools and methods, the U.S. Geological Survey (USGS) created a set of educational lessons based on the RMS Titanic's April 1912 sailing. With these lessons, student researchers can learn about latitude and longitude, map projections, ocean currents, databases, maps, and images through the analysis of the route, warnings, sinking, rescue, and eventual discovery of the submerged ocean liner in 1985. They can also consider the human and physical aspects of the maiden voyage in the North Atlantic Ocean at a variety of scales, from global to regional to local. Likewise, their investigations can reveal how the sinking of the Titanic affected future shipping routes.

Kerski, J. J.

2004-01-01

378

Hydrocarbon lakes on Titan  

NASA Astrophysics Data System (ADS)

The Huygens Probe detected dendritic drainage-like features, methane clouds and a high surface relative humidity (˜50%) on Titan in the vicinity of its landing site [Tomasko, M.G., and 39 colleagues, 2005. Nature 438, 765-778; Niemann, H.B., and 17 colleagues, 2005. Nature 438, 779-784], suggesting sources of methane that replenish this gas against photo- and charged-particle chemical loss on short (10-100) million year timescales [Atreya, S.K., Adams, E.Y., Niemann, H.B., Demick-Montelara, J.E., Owen, T.C., Fulchignoni, M., Ferri, F., Wilson, E.H., 2006. Planet. Space Sci. In press]. On the other hand, Cassini Orbiter remote sensing shows dry and even desert-like landscapes with dunes [Lorenz, R.D., and 39 colleagues, 2006a. Science 312, 724-727], some areas worked by fluvial erosion, but no large-scale bodies of liquid [Elachi, C., and 34 colleagues, 2005. Science 308, 970-974]. Either the atmospheric methane relative humidity is declining in a steady fashion over time, or the sources that maintain the relative humidity are geographically restricted, small, or hidden within the crust itself. In this paper we explore the hypothesis that the present-day methane relative humidity is maintained entirely by lakes that cover a small part of the surface area of Titan. We calculate the required minimum surface area coverage of such lakes, assess the stabilizing influence of ethane, and the implications for moist convection in the atmosphere. We show that, under Titan's surface conditions, methane evaporates rapidly enough that shorelines of any existing lakes could potentially migrate by several hundred m to tens of km per year, rates that could be detected by the Cassini orbiter. We furthermore show that the high relative humidity of methane in Titan's lower atmosphere could be maintained by evaporation from lakes covering only 0.002-0.02 of the whole surface.

Mitri, Giuseppe; Showman, Adam P.; Lunine, Jonathan I.; Lorenz, Ralph D.

2007-02-01

379

NPR: Titanic Baby  

NSDL National Science Digital Library

This Web site contains an audio file of a story broadcast on National Public Radio earlier this month. The broadcast relates the poignant story of a four-year effort to identify the exhumed body of a 13-month-old child who died in the Titanic disaster. A metal medallion buried with the body serendipitously preserved a bit of the wrist bone, from which forensic scientists could extract mitochondrial DNA and eventually find the child's living relatives.

2002-01-01

380

Crystalline titanate catalyst supports  

DOEpatents

A series of new crystalline titanates (CT) are shown to have considerable potential as catalyst supports. For Pd supported catalyst, the catalytic activity for pyrene hydrogenation was substantially different depending on the type of CT, and one was substantially more active than Pd on hydrous titanium oxide (HTO). For 1-hexene hydrogenation the activities of the new CTs were approximately the same as for the hydrous metal oxide supports.

Anthony, Rayford G. (Bryan, TX); Dosch, Robert G. (Albuquerque, NM)

1993-01-01

381

Crystalline titanate catalyst supports  

DOEpatents

A series of new crystalline titanates (CT) are shown to have considerable potential as catalyst supports. For Pd supported catalyst, the catalytic activity for pyrene hydrogenation was substantially different depending on the type of CT, and one was substantially more active than Pd on hydrous titanium oxide (HTO). For 1-hexene hydrogenation the activities of the new CTs were approximately the same as for the hydrous metal oxide supports.

Anthony, R.G.; Dosch, R.G.

1993-01-05

382

Titan’s “blandlands”: nature, distribution, and possible origin of Titan’s plains  

NASA Astrophysics Data System (ADS)

Titan’s diverse and Earth-like geologic features have been mapped and interpreted based on their morphological characteristics (e.g. Lopes et al., 2010, Icarus 205; Aharonson et al., 2012, Titan: Surface, Atmosphere, Magnetosphere, Cambridge University Press). While the interpretation for the origin of some units, such as dunes and well-preserved impact craters, has been relatively straightforward, others have been more challenging. In particular, the undifferentiated plains first mapped by Lopes et al. (2010) remain mysterious. These vast expanses, often referred to as “blandlands” (also “undifferentiated plains unit”, Lopes et al., 2010) are mostly found at mid-latitudes and appear relatively featureless at radar wavelengths, with no significant topography. Their gradational boundaries and paucity of features in SAR data make geologic interpretation particularly challenging. We examine and evaluate different formation mechanisms. Plains may be sedimentary in origin, resulting from fluvial or lacustrine deposition or accumulation of photolysis products created in the upper atmosphere. Alternatively, the plains may be cryovolcanic, consisting of overlapping flows of low relief, obscured by accumulation of sediments. In this paper, we use SAR, radiometry, scatterometry, and SARTopo data to examine the characteristics of the plains and compare them with other geologic units. We also compare their global distribution with that of other units and examine the implications.

Lopes, Rosaly M.; Malaska, M. J.; Le Gall, A.; Hayes, A.; Mitchell, K. L.; Kirk, R.; Radebaugh, J.; Neish, C.; Stofan, E.; Janssen, M.; Wall, S. D.; Lucas, A.; Lorenz, R. D.; Cassini RADAR Team

2013-10-01

383

Hydrothermal synthesis of sodium bismuth titanate and titanate nanofibers  

Microsoft Academic Search

A hydrothermal processing method was developed for the synthesis of sodium bismuth titanate powders and thin films from suitable precursors at 150°C. Oxide precursors were best suited for preparing pure phase materials. The sodium bismuth titanate powders consisted of cube shaped crystals. A modified solution-reprecitation model involving partial dissolution of the precursors was proposed to explain the growth of these

Animesh Kundu

2008-01-01

384

Synthesis and electrical analysis of nano-crystalline barium titanate nanocomposites for use in high-energy density applications.  

SciTech Connect

Ceramic based nanocomposites have recently demonstrated the ability to provide enhanced permittivity, increased dielectric breakdown strength, and reduced electromechanical strain making them potential materials systems for high energy density applications. A systematic characterization and optimization of barium titanate and PLZT based nanoparticle composites employing a glass or polymer matrix to yield a high energy density component will be presented. This work will present the systematic characterization and optimization of barium titanate and lead lanthanum zirconate titanate nanoparticle based ceramics. The nanoparticles have been synthesized using solution and pH-based synthesis processing routes and employed to fabricate polycrystalline ceramic and nanocomposite based components. The dielectric/ferroelectric properties of these various components have been gauged by impedance analysis and electromechanical response and will be discussed.

DiAntonio, Christopher Brian; Yang, Pin; Chavez, Tom P.; Huber, Dale L.; Winter, Michael R.; Monson, Todd C.; Roesler, Alexander William

2010-10-01

385

Enthalpy of formation of zircon  

SciTech Connect

Using high-temperature solution calorimetry in molt 2PbO {center dot} B{sub 2}O{sub 3}, the enthalpy of reaction of the formation of zircon, ZrSiO{sub 4}, from its constituent oxides has been determined: {Delta}{sub 4}H{sub 977}(ZrSiO{sub 4}) = {minus}27.9 ({plus minus}1.9) kJ/mol. With previously reported data for the heat contents of ZrO{sub 2} SiO{sub 2} and ZrSiO{sub 4} and standard-state enthalpies of formation of ZrO{sub 2} and SiO{sub 2}, we obtain {Delta}{sub f}H{sub 298}{degrees}. (ZrSiO{sub 4}) = {minus}2034.2 ({plus minus}3.1) kJ/mol and {Delta}{sub t}G{sub 298}{degrees} (ZrSiO{sub 4}) = {minus}1919.8 kJ/mol. The free energy value is in excellent agreement with a range previously estimated from solid-state reaction equilibria. At higher temperature also the data are in close agreement with existing data, though the data sets diverge somewhat with increasing T. In this paper the limitations of the data for predicting the breakdown temperature of zircon into its constituent oxides are discussed.

Ellison, A.J.G. (Materials Science Div., Argonne National Lab., Argonne, IL (US)); Navrotsky, A. (Dept. of Geological and Geophysical Sciences, Princeton Univ., Princeton, NJ (US))

1992-06-01

386

Titan's neutral atmospheric composition  

NASA Astrophysics Data System (ADS)

Our understanding of Titan's atmospheric chemical composition has recently been enhanced by the data returned by the Cassini instruments. Spectra recorded by the Composite Infrared Spectrometer (CIRS) aboard the Cassini spacecraft have been processed from the Titan flybys spanning three years now since SOI (Flasar et al., 2005; Teanby et al., 2006, Vinatier et al., 2006; Nixon et al., 2006; Coustenis et al., 2007). The spectra characterize various regions on Titan from 85°S to 80°N with a variety of emission angles. We have studied the emission observed in the CIRS detector arrays (covering the 10-1500 cm-1 spectral range with apodized resolutions of 2.54 or 0.53 cm-1). We have used temperature profiles retrieved from the inversion of the emission observed in the methane v4 band at 1304 cm-1 and a line-by-line radiative transfer code to infer the abundances of the trace constituents and some of their isotopes in Titan's stratosphere (Coustenis et al., 2007a). The composite spectra show several signatures of previously identified molecules: hydrocarbons, nitriles, H2O and CO2. Besides these well-known trace species, a firm detection of benzene (C6H6) is provided by CIRS at 674 cm-1 and allows for the study of its latitudinal variations. No longitudinal variations were found for any of the gases. Information is retrieved on the meridional variations of the trace constituents and tied to predictions by dynamicalphotochemical models (Hourdin et al., 2004; Lavvas et al., 2007). Molecules showing a significant enhancement at northern latitudes are the nitriles (HC3N, HCN) and the complex hydrocarbons (C4H2, C3H4). The D/H ratio on Titan was also determined from the CH3D band at 8.6 micron and found to be about 1.3 ±0.2 10-4. We have also identified the presence of C2HD at 678 cm-1 for the first time (Coustenis et al., 2007b, in preparation). Constraints are also set on the vertical distribution of C2H2. References : Coustenis et al., 2007a, Icarus, in press; Flasar et al., 2005, Science 308, 975 ; Hourdin et al., 2004, J. Geophys. Res. 109, E1205; Nixon et al., 2006, BAAS 38; Lavvas et al., 2007, Plan. Space Sci., in press; Teanby et al., 2006, Icarus 181, 243; Vinatier et al., 2006, Icarus, 188, 120.

Coustenis, A.; Jennings, D.; Jolly, A.; Bénilan, Y.; Vinatier, S.; Nixon, C.; Gautier, D.; Bjoraker, G.; Romani, P.; Flasar, M.

2007-08-01

387

Truss Structure Integrity Identification Using PZT Sensor-Actuator  

Microsoft Academic Search

This paper presents a frequency domain impedance-signature-based technique for health monitoring of an assembled truss structure. Unlike conventional modal analysis approaches, the technique uses piezoceramic (PZT) elements as integrated sensor-actuators for acquisition of signature pattern of the truss. The concept of the localization of sensing\\/actuation area for damage detection of an assembled structure is presented for the first time. Through

F. P. Sun; Z. Chaudhry; C. Liang; C. A. Rogers

1995-01-01

388

Titan after Cassini Huygens  

NASA Astrophysics Data System (ADS)

In 2005, the Huygens Probe gave us a snapshot of a world tantalizingly like our own, yet frozen in its evolution on the threshold of life. The descent under parachute, like that of Huygens in 2005, is happening again, but this time in the Saturn-cast twilight of winter in Titan's northern reaches. With a pop, the parachute is released, and then a muffled splash signals the beginning of the first floating exploration of an extraterrestrial sea-this one not of water but of liquid hydrocarbons. Meanwhile, thousands of miles away, a hot air balloon, a "montgolfiere," cruises 6 miles above sunnier terrain, imaging vistas of dunes, river channels, mountains and valleys carved in water ice, and probing the subsurface for vast quantities of "missing" methane and ethane that might be hidden within a porous icy crust. Balloon and floater return their data to a Titan Orbiter equipped to strip away Titan's mysteries with imaging, radar profiling, and atmospheric sampling, much more powerful and more complete than Cassini was capable of. This spacecraft, preparing to enter a circular orbit around Saturn's cloud-shrouded giant moon, has just completed a series of flybys of Enceladus, a tiny but active world with plumes that blow water and organics from the interior into space. Specialized instruments on the orbiter were able to analyze these plumes directly during the flybys. Titan and Enceladus could hardly seem more different, and yet they are linked by their origin in the Saturn system, by a magnetosphere that sweeps up mass and delivers energy, and by the possibility that one or both worlds harbor life. It is the goal of the NASA/ESA Titan Saturn System Mission (TSSM) to explore and investigate these exotic and inviting worlds, to understand their natures and assess the possibilities of habitability in this system so distant from our home world. Orbiting, landing, and ballooning at Titan represent a new and exciting approach to planetary exploration. The TSSM mission architecture inherently provides the optimal balance between science, risk, and cost using three guiding principles: Achieve science well beyond the high bar set by Cassini Huygens. The TSSM orbiter, lander, and balloon have been configured with instruments and operational concept that go well beyond Cassini-Huygens capabilities, thus ensuring dramatic remote observation and in situ science discoveries. Build upon successful design and operational experience and lessons learned. ESA has successful experience in designing and landing probes on Titan (Huygens), as does NASA in implementing an orbiter at Saturn (Cassini). Long life design rules and extensive operational experience in the Saturn system have been applied to form the TSSM concept. Lessons learned from Galileo, Cassini, New Horizons, and MRO have been applied to reduce risk and lower cost. Development by ESA of the montgolfiere combines prior experience with Earth and planetary balloon systems to enable innovative science and unprecedented mobility for surface exploration. Strong international partnership. TSSM represents a collaborative effort between NASA and ESA that is structured to provide the best possible mission at a reasonable cost to NASA and to ESA. This NASA-ESA partnership leverages resources to maximize science return, distribute risk, and ensure technical readiness.

Beauchamp, P. M.; Lunine, J.; Lebreton, J.; Coustenis, A.; Matson, D.; Reh, K.; Erd, C.

2008-12-01

389

Assessment of PZT transducer bonding techniques under drop-weight impact loading in composites  

Microsoft Academic Search

This paper describes the robustness of a structural health monitoring system (SHM) that utilizes lead-zirconatetitanate (PZT) transducers tested on carbon fibre composite coupons under drop-weight impact loading. Four PZT transducers are attached to the surface of 10.16 cm x 15.24 cm aerospace grade carbon fibre coupons using four types of adhesives: cyanoacrylate, epoxy, methyl methacrylate, and silicon. Each PZT transducer

Kyle R. Mulligan; Pierre-Claude Ostiguy; Patrice Masson; Saïd Elkoun; Nicolas Quaegebeur

2011-01-01

390

Nondestructive Evaluation of Polarization in LTCC\\/PZT Piezoelectric Modules by Thermal Wave Methods  

Microsoft Academic Search

This work investigates the polarization behavior of low-temperature cofired ceramic (LTCC)\\/PZT sensor-actuator-modules fabricated by packaging of ceramic PZT plates between alumosilicate-corundum LTCC green layers and subsequent sintering at elevated temperatures. Polarization evaluation was done by applying the laser intensity modulation method (LIMM) where a thermal wave travelling into the ferroelectric PZT ceramic plate is generated by an intensity-modulated laser beam.

G. Suchaneck; W. Hu; G. Gerlach; M. Flössel; S. Gebhardt; A. Schönecker

2011-01-01

391

Correlation of materials and ferroelectric properties of sputtered and sol-gel PZT films  

Microsoft Academic Search

The processes for the physical vapor deposition (PVD) of Pb(Zr,Ti)O3 (PZT) thin films from two different composite oxide targets has been demonstrated. PZT thin films have been deposited by both PVD or sputter technique and standard sol-gel method. Half micron PZT films were deposited by both methods on identical substrates (Si[(100) 4 inch Cz wafer]\\/SiO2\\/Ti-TiO2\\/Pt) followed by sputter-deposited Pt top

R. X. Fu; R. Mamazza; T. S. Zheleva; K. W. Kirchner; B. H. Piekarski

2009-01-01

392

The Observational Program and Research Tests of an Automatic PZT with Prolonged Exposure  

NASA Astrophysics Data System (ADS)

The theory and instrumentation of the PZT have been described by several authors. In comparison to other techniques available for the determination of Earth Rotation Parameters (ERP), the PZT has many advantages. Among these are its rigid construction, elimination of levelling errors, minimization of refraction errors, ease of operation, etc. Among the disadvantages of a PZT are its limited field of view by which few stars can be observed.

Gao, Buxi; Li, Jinfeng

1991-03-01

393

PZT\\/polymer flexible composites for embedded actuator and sensor applications  

Microsoft Academic Search

Currently, smart structures utilize both polymeric sensor and PZT-based actuators. Polymeric sensors based upon PVDF are limited to about 70 degrees C operating temperature, while PZT-based actuators are inflexible. This paper examines the use of PZT\\/polymer composites for smart materials applications. Both ferroelectric (VDF) and non- ferroelectric high temperatuer polymers were studied. High temperature composite sensors were fabricated exhibiting g31

Witold Kowbel; Xiaoxin Xia; W. Champion; James C. Withers; Ben K. Wada

1999-01-01

394

Properties of thick PZT films prepared by modified metal organic decomposition process  

Microsoft Academic Search

Characteristics of PZT films synthesized by using a modified metal-organic decompositions (MOD) process, which is the spin-coating of a nano-powder incorporated PZT carbaxylate solution, was examined. A deposition rate as large as 0.27 ? m per layer is achieved by carefully adjusting the concentration of carboxylate solution (0.4 M) and spin-coating process (2000 rpm). PZT films thus obtained possess good

Yi-Nein Lai; Cheng-Hsiung Lin; Hsiu-Fung Cheng; I-Nan Lin

2001-01-01

395

The commercial Titan launch vehicle  

NASA Astrophysics Data System (ADS)

Martin Marietta is making available a commercial version of the Titan launch vehicle. At a total payload weight capability of 31,600 pounds to low earth orbit, the commercial Titan provides Shuttle and Ariane compatible services to the commercial satellite community. This paper describes the commercial Titan which is based on the U.S. Air Force Titan 34D. A large diameter payload fairing and extension module provide for single or dual payload installation. Structural and some equipment rearrangement modifications have been made to the Stage II forward skirt to handle the larger payload fairing and loads involved in commercial operation. Stage II has been stretched and the liquid rocket engines enhanced to improve lift performance. The solid rocket motors and avionics remain unchanged. Plans to utilize Transtage on top a Titan III for direct injection into geosynchronous transfer orbit are being studied for future launches.

Troutman, J.; Isakowitz, S.

1987-06-01

396

Properties of PZT/SiC composites processed by solid state diffusion  

NASA Astrophysics Data System (ADS)

PZT/SiC composites were fabricated by a heterogeneous precipitation followed by a solid state diffusion process. The content of SiC increased with increasing heating temperature of the solid state diffusion process. SEM showed that microstructures of PZT ceramics and composites were similar, and TEM and EDS showed that SiC only located at the grain boundaries. The mechanical properties were improved markedly, and the dielectric breakdown voltage of PZT/SiC composites increases by 80% compared to that of uncomposited PZT ceramics, which can bring a 200% increase in the energy storage density while maintaining the level of dielectric constant, piezoelectric and ferroelectric properties.

Chen, Heng; Yang, Hong; Dong, Xianlin; Wang, Yongling

2006-06-01

397

Zircon dating of oceanic crustal accretion.  

PubMed

Most of Earth's present-day crust formed at mid-ocean ridges. High-precision uranium-lead dating of zircons in gabbros from the Vema Fracture Zone on the Mid-Atlantic Ridge reveals that the crust there grew in a highly regular pattern characterized by shallow melt delivery. Combined with results from previous dating studies, this finding suggests that two distinct modes of crustal accretion occur along slow-spreading ridges. Individual samples record a zircon date range of 90,000 to 235,000 years, which is interpreted to reflect the time scale of zircon crystallization in oceanic plutonic rocks. PMID:19179492

Lissenberg, C Johan; Rioux, Matthew; Shimizu, Nobumichi; Bowring, Samuel A; Mével, Catherine

2009-01-29

398

Elastic softening of zircon by radiation damage  

SciTech Connect

The bulk modulus and the shear modulus of zircon soften by ca. 50% when zircon is amorphized by radiation damage. A theoretical description of the experimental findings is presented which shows that the elastic response on a zircon ceramics with radiation damage follows Hashin-Shtrikman [J. Mech. Phys. Solids 11, 127 (1963)] behavior with very narrow bounds. The elastic response depends, in good approximation, on the square of the volume fraction f{sub a} of the amorphized regions. In a slightly coarser approximation one finds an almost linear interpolation of the bulk and the shear modulus between those of the crystalline state and those of the fully amorphous state.

Salje, Ekhard K. H. [Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ (United Kingdom)

2006-09-25

399

Sputtered highly oriented PZT thin films for MEMS applications  

NASA Astrophysics Data System (ADS)

Recently there has been an explosion of interest in the field of micro-electro-mechanical systems (MEMS). MEMS device technology has become critical in the growth of various fields like medical, automotive, chemical, and space technology. Among the many applications of ferroelectric thin films in MEMS devices, microfluidics is a field that has drawn considerable amount of research from bio-technology industries as well as chemical and semiconductor manufacturing industries. PZT thin films have been identified as best suited materials for micro-actuators and micro-sensors used in MEMS devices. A promising application for piezoelectric thin film based MEMS devices is disposable drug delivery systems that are capable of sensing biological parameters, mixing and delivering minute and precise amounts of drugs using micro-pumps or micro mixers. These devices call for low driving voltages, so that they can be battery operated. Improving the performance of the actuator material is critical in achieving battery operated disposal drug delivery systems. The device geometry and power consumption in MEMS devices largely depends upon the piezoelectric constant of the films, since they are most commonly used to convert electrical energy into a mechanical response of a membrane or cantilever and vice versa. Phenomenological calculation on the crystal orientation dependence of piezoelectric coefficients for PZT single crystal have reported a significant enhancement of the piezoelectric d33 constant by more than 3 times along [001] in the rhombohedral phase as compared to the conventionally used orientation PZT(111) since [111] is the along the spontaneous polarization direction. This could mean considerable improvement in the MEMS device performance and help drive the operating voltages lower. The motivation of this study is to investigate the crystal orientation dependence of both dielectric and piezoelectric coefficients of PZT thin films in order to select the appropriate orientation that could improve the MEMS device performance. Potential application of these devices is as battery operated disposable drug delivery systems. This work will also investigate the fabrication of a flexural plate wave based microfluidic device using the PZT thin film of appropriate orientation that would enhance the device performance. (Abstract shortened by UMI.)

Kalpat, Sriram S.

400

Titan's atmosphere from DISR  

NASA Astrophysics Data System (ADS)

This abstract distills information about Titan's atmosphere described in detail in a paper by M. G. Tomasko, L. Doose, S. Engel, L. E. Dafoe, R. West, M. Lemmon, E. Karkoschka and C. See, ‘A model of Titan's aerosols based on measurements made inside the atmosphere', Planetary and Space Sciences, in press, 2008. The Descent Imager Spectral Radiometer (DISR) observed Titan's sky and surface during the descent of the Huygens Probe in January, 2005. Measurements were made over the altitude range 160 Km to the surface near latitude -10 degrees. The DISR instrument package included several components to measure the radiation state as a function of altitude. These include upward and downward-looking visible and near-infrared spectrometers covering the wavelength range 450 to 1600 nm, an ultraviolet photometer, a solar aureole camera with polarizers, and a sun sensor. Measurements were made at a variety of azimuthal angles relative to the sun azimuth. Due to unanticipated behavior of the probe (reverse spin and high-amplitude, chaotic tip and tilt) the retrieval process has required more effort than was planned and the total science return is less than expected. Nevertheless the data yielded unsurpassed and unique information which constrain the optical and physical properties of the photochemical haze aerosols and condensate particles. The principal findings are (1) between 80 Km and 160 Km the photochemical haze is well mixed with the gas with a scale height of about 65 Km, (2) between 80 Km and the surface the particle optical depth is a linear function of altitude with a break in slope near 30 Km altitude, (3) optical properties of the haze do not depend much on altitude above 80 Km although more recent work by Tomasko and colleagues suggest a gradient in the stratosphere; below 80 Km there are changes in optical behavior which suggest that condensation plays a role, (4) the data confirm previous results which proposed a particle structure of aggregates of small monomers, but the DISR data indicate somewhat smaller monomer radius ( 0.05 micro meters) and many more total monomers ( 3000) in the average particle, and (5) above 80 Km altitude particle refractive indices are similar to what is expected from laboratory measurements for tholin (Khare, B. N., Sagan, C., Arakawa, E. T., Suits, F., Calcott, T. A., Williams, M. W., ‘Optical constants of organic tholins produced in a simulated Titanian atmosphere: from X-ray to microwave frequencies', Icarus 60, 127-137, 1984) but below 80 Km there is less absorption suggesting that condensates play a role. The analyses of DISR data also led to a revision of near-infrared methane absorption coefficients under Titan conditions (M. G. Tomasko, B. Bézard , L. Doose, S. Engel, and E. Karkoschka, e ‘Measurements of Methane Absorption by the Descent Imager/Spectral Radiometer (DISR) During its Descent through Titan's Atmosphere', Planetary and Space Sciences, in press, 2008) and to a much-improved determination of the radiation budget which is important for dynamics and climate studies (M. G. Tomasko, B. Bézard , L. Doose, S. Engel, E. Karkoschka and S. e Vinatier, ‘Heat Balance in Titan's Atmosphere', Planetary and Space Sciences, in press, 2008).

West, Robert

401

Carbon isotopic enrichment in Titan's tholins? Implications for Titan's aerosols  

NASA Astrophysics Data System (ADS)

Since the discovery of the main composition of Titan's atmosphere, many laboratory experiments have been carried out to mimic its chemical evolution, and more particularly the formation of the organic haze particles widespread in this atmosphere. Indeed, some of these simulation experiments produce a solid phase - named Titan's tholins - that is assumed to get properties analogous to the Titan's aerosols ones. We have studied the possible isotopic fractionation of carbon during the processes involved in the formation of Titan's tholins, using tholins obtained from different simulation experiments. It's an important issue because it can provide information on the processes of tholins formation. We will present the first results obtained on the 12 C/13 C isotopic ratios measured on Titan's tholins synthesized in laboratory with cold plasma discharges. Measurements of isotopic enhancement in 13 C (? 13 C), done both on tholins and on the initial gas mixture (N2 :CH4 (98:2)) used to produce them, do not show any clear deficit or enrichment in 13 C relatively to 12 C in the synthesised tholins, compared to the initial gas mixture. Preliminary retrieving of the data of the Aerosol Collector and Pyrolyzer (ACP) experiment of the Huygens probe suggests that Titan's aerosols may also not present carbon isotopic enrichment. This observation allows to go further in the analyses of the ACP experiment data. We are also focusing on the evolution of Titan's tholins under acid hydrolysis treatment. This strong treatment aims to reproduce the evolution of Titan's aerosols in contact with ice water under a longer time scale. Preliminary results on the analyses of the obtained products could give guides lines to identify the still unspecified matter that takes part to the Titan's surface reflectivity decrease as observed by the DISR instrument. This study is still in progress.

Nguyen, M.-J.; Raulin, F.; Coll, P.; Derenne, S.; Szopa, C.; Cernogora, G.; Israel, G.; Bernard, J.-M.

402

Recrystallisation of Strontium Titanate.  

NASA Astrophysics Data System (ADS)

The recrystallisation rate of amorphous strontium titanate is dramatically enhanced by thermal annealing in water vapour as compared with a dry ambient. Time resolved optical reflectivity (TRR) has been combined with Rutherford backscattering spectrometry (RBS) and ion channelling to investigate this effect. Thin amorphous films were produced on single crystal substrates of (100) strontium titanate by ion bombardment. Specimens were annealed under controlled ambient conditions and the solid phase epitaxial recrystallisation monitored in situ by TRR. The TRR data were calibrated ex situ by RBS measurements. Isotope substitution, nuclear reaction analysis and secondary ion mass spectrometry were utilised to reveal the uptake of hydrogen and oxygen into the implanted layer. Hydrogen is identified as the species which penetrates to the crystal/amorphous interface. It is shown that the recrystallisation rate is proportional to the concentration of diffusing hydrogen at the interface. The data show that the effect of water vapour, or more precisely hydrogen, is to reduce the activation energy of recrystallisation from 2.1 to 1.0 eV. It is concluded that hydrogen, provided by the dissociation of water molecules at the surface, is a catalyst in the crystallisation of strontium titanate. The approach used in this study is seen to have application to a wider class of thin film phase changes and reactions. We have applied TRR to measure the temperature dependance of the amorphous to gamma and the gamma to alpha phase transitions in Al_2O _3 (sapphire). TRR has also been utilised to measure the thermal oxidation rate of single crystal silicon in a water vapour ambient.

Simpson, Todd William

403

Zirconate pyrochlores under high pressure  

SciTech Connect

Ab initio total-energy calculations and x-ray diffraction measurements have been combined to study the phase stability of zirconate pyrochlores (A2Zr2O7; A=La, Nd and Sm) under pressures up to 50 GPa. Phase transformations to the defect-cotunnite structure are theoretically predicted at pressures of 22, 20 and 18 GPa, in excellent agreement with the experimentally determined values of 21, 22 and 18 GPa for La2Zr2O7, Nd2Zr2O7 and Sm2Zr2O7, respectively. Analysis of the elastic properties indicate that elastic anisotropy may be one of the driving forces for the pressure-induced cubic-to-noncubic phase transformation.

Xiao, Haiyan [Pacific Northwest National Laboratory (PNNL); Zhang, Fuxiang [University of Michigan; Gao, Fei [Pacific Northwest National Laboratory (PNNL); Ewing, Rodney C. [University of Michigan; Weber, William J [ORNL

2010-01-01

404

Zirconate pyrochlores under high pressure  

SciTech Connect

Ab initio total-energy calculations and x-ray diffraction measurements have been combined to study the phase stability of zirconate pyrochlores (A2Zr2O7; A=La, Nd and Sm) under pressures up to 50 GPa. Phase transformations to the defect-cotunnite structure are theoretically predicted at pressures of 22, 20 and 18 GPa, in excellent agreement with the experimentally determined values of 21, 22 and 18 GPa for La2Zr2O7, Nd2Zr2O7 and Sm2Zr2O7, respectively. Analysis of the elastic properties indicates that elastic anisotropy may be one of the driving forces for the pressure-induced cubic-to-noncubic phase transformation.

Xiao, Haiyan Y.; Zhang, F. X.; Gao, Fei; Lang, Maik; Ewing, Rodney C.; Weber, William J.

2010-07-12

405

Ethane ocean on titan.  

PubMed

It is proposed that Saturn's satellite Titan is covered by an ocean one to several kilometers deep consisting mainly of ethane. If the ocean is in thermodynamic equilibrium with an atmosphere of 3 percent (mole fraction) methane, then its composition is roughly 70 percent ethane, 25 percent methane, and 5 percent nitrogen. Photochemical models predict that ethane is the dominant end product of methane photolysis so that the evolving ocean is both the source and sink for continuing photolysis. The coexisting atmosphere is compatible with Voyager data. PMID:17806723

Lunine, J I; Stevenson, D J; Yung, Y L

1983-12-16

406

TitanPad  

NSDL National Science Digital Library

If you're looking to work with colleagues who might be located in different places, TitanPad might be just the application you require. The application can be customized for a number of different uses, but at its essence it provides a shared space for visitors to coordinate work on documents and to also discuss their work via a specialized chat window. Visitors don't need to sign up, and the site also includes a blog for information about updates and so on. This version is compatible with all operating systems.

407

Titan's Carbon Conundrum  

NASA Astrophysics Data System (ADS)

As recently as a year ago, a consensus was emerging that carbon-13 in Titan's methane was enriched by some ~10% over the terrestrial value (12C/13C = ~77-82 on Titan versus 89 on Earth, Niemann et al 2005, Nixon et al 2008). At the same time, several measurements of 12C/13C in ethane, the main product of methane photolysis, appeared to show no enrichment (Nixon et al 2008, Jennings et al 2009). This led to the suggestion that a steady state equilibrium was being reached, with a Kinetic Isotope Effect (KIE) in a key reaction (C2H + CH4 ? C2H2 + CH3) responsible for the slight enrichment in the atmospheric reservoir relative to both the incoming flux of methane and outgoing flux of ethane (Jennings et al 2009). This paradigm was overturned earlier this year when the Huygens GCMS team revised their measurement of 12CH4/13CH4 upwards to agree with the terrestrial value (Niemann et al, in preparation), eliminating any need for the KIE fractionation. However, this presents a new problem in the sense that the KIE effect is probably real - it is confirmed for the CH3D and 12CH4 reactions with ethynyl (Opansky and Leone 1996), so almost certainly for 13CH4-12CH4 pair as well - and so some fractionation of methane should be occurring. This is true regardless as to whether the atmospheric methane is being replenished or not - differing only in degree - provided the ethynyl abstraction reaction is the dominant path for methane loss as predicted by current models (Lavvas et al. 2008). In this forum we will present updated measurements by the CIRS team of the 12CH4/13CH4 derived from recent high signal-to-noise Titan observations, and discuss the degree of agreement with both the earlier published ratios, and the newer revised GCMS results. We will also discuss the implications for Titan's methane evolution over geologic time including clues from the D/H ratio. We conclude by highlighting the currently open questions and avenues for future work. Jennings, D.E. et al., J. Chem. Phys., 113(42), 11101-11106, 2009. Lavvas, P.P. et al., Plan. Space Science, 56, 27-66, 2008. Niemann, H.B. et al., Nature, 438, 779-784, 2005. Nixon, C.A. et al., Icarus, 195, 778-791, 2008. Opansky, B.J and S.R. Leone, J. Phys. Chem., 100, 4888-4892, 1996.

Nixon, C. A.; Jennings, D. E.; Teanby, N. A.; Vinatier, S.; BÉ Zard, B.; Coustenis, A.; Irwin, P. G.; Flasar, F. M.; Cassini Cirs Team

2010-12-01

408

Hydrothermal synthesis of sodium bismuth titanate and titanate nanofibers  

NASA Astrophysics Data System (ADS)

A hydrothermal processing method was developed for the synthesis of sodium bismuth titanate powders and thin films from suitable precursors at 150°C. Oxide precursors were best suited for preparing pure phase materials. The sodium bismuth titanate powders consisted of cube shaped crystals. A modified solution-reprecitation model involving partial dissolution of the precursors was proposed to explain the growth of these particles. The thin films were prepared on strontium titanate (100) substrate. A sample holder was specially designed and fabricated to secure the substrates in the reaction vessel. The result was a relatively smooth film of thickness ?550 nm. The films were essentially single crystalline and had strong epitaxial relationship with the substrate. Titanate nanofibers (NaxH yTinO2n+1° zH2O) were known to form under similar hydrothermal conditions as sodium bismuth titanate powders. Detail research revealed that the pure hydroxide and oxide precursors tend to form sodium bismuth titanate powders or thin films. Titanate nanofibers were the predominant product when any other ions or organics were present in the precursor. Much faster reaction kinetics for the formation of nanofibers was observed when certain organic compounds were added deliberately with the precursors. Accordingly, a hydrothermal process was developed for converting the precursors to titanate nanofibers in a significantly shorter time than reported in the literature. A thin film consisting of vertically aligned nanofibers was prepared on titanium substrate at 150°C in as little as 30 minutes. Complete conversion of starting precursors to free standing nanofibers was achieved in ˜8 hours at 150°C. The as-prepared nanofibers were some form of sodium titanate. They were converted to hydrogen titanate by ion exchange. Differential Scanning calorimetric experiments were performed to understand the thermal evolution of the fibers. The hydrogen titanate fibers underwent structural modifications even at temperatures less than 100°C. Research was done to understand the structure of these hydrogen titanate nanofibers with the aid of HRTEM, simulation of HRTEM images and x-ray diffraction. Initial results revealed that the fibers observed under the microscope had either a lepidocrocite type structure or an anatase type structure.

Kundu, Animesh

409

Zircon saturation in lunar basalts and granites  

NASA Astrophysics Data System (ADS)

The saturation surface for zircon in late-stage lunar basalts and granites has been determined over the temperature range 1400-1070 C. The saturation surface in the basalt shows a strong temperature dependence from 1400 to 1200 C. Below 1200 deg, the saturation surface turns down sharply and becomes nearly temperature independent. The saturation surface in the granitic composition is similar to the basaltic composition, although less Zr is required for saturation. At 1100 C, 9000 ppm Zr and 5000 ppm Zr are required for zircon saturation in the basalt and granite, repectively. If a magma with chondritic Zr content is assumed, then zircon saturation would not be reached until 99.96-99.92% crystallization. This precludes zircon crystallization playing a major role in the trace element evolution of lunar magmas.

Dickinson, J. E.; Hess, P. C.

1982-02-01

410

Recovery of Zircon from Investment Casting Molds.  

National Technical Information Service (NTIS)

The Bureau of Mines conducted physical and chemical beneficiation studies on three samples of waste investment casting molds to devise a method to liberate and recover zircon. Rod mill grinding, autogenous attrition grinding, and caustic leaching were lib...

C. W. Smith T. O. Llewellyn

1985-01-01

411

Titan's astrobiology: some new data  

NASA Astrophysics Data System (ADS)

The Cassini-Huygens observations of Titan have strongly strengthened its astrobiological impor-tance, clearly showing that Titan is one of the key planetary bodies for astrobiological studies. Indeed the Cassini-Huygens data show that there are many similarities which can be found when comparing Titan and the early Earth, in spite of much lower temperatures for Titan. One of these similarities is the presence of an active and complex organic chemistry in Titan's environment, which occurs from the high atmosphere to the surface and very likely in the sub-surface. This organic chemistry involves several of the key compounds of terrestrial prebiotic chemistry, and it represents, by itself, a major astrobiological aspect of Titan. Moreover, the potential presence of an internal water-ocean makes Titan a potential habitable environment, of obvious astrobiological importance. In fact, after five years of close observation by remote sensing and in situ instrumentations from the Cassini-Huygens mission, Titan does not look any more like a frozen primitive Earth, but it looks like an evolving planet, geologically active, with cryo-volcanism, eolian erosion, clouds and precipitations, and a methane cycle analogous to the water cycle on Earth. But the new data also show that a complex organic chemistry is taking place in the very high atmospheric layers of the satellite, with the formation in the ionosphere of high molecular weight (up about 10 000 Daltons) ions. Are these ions abundant enough in the lower atmosphere zones to act as organic monomers which then grow by aggregation, sedimentation and condensation down to the surface? This is one of the key questions that chemical models have now to answer. Cassini-Huygens observations have shown that there is no large surface ocean on Titan, but large regional lakes which behave like evolving liquid media. Those lakes are probably accumulating complex organics of astrobiological interest, including organic aerosols, and could be a prime astrobiologically oriented target for future exploration of Saturn's largest satellite. Cassini-Huygens has shown that the chemical composition of Titan's aerosols is similar to that of laboratory Titan's tholins. The behavior of those tholins when sub-mitted to high solar UV radiation has recently been studied in Earth orbit. The results show a slight but complex photodegradation in some cases. Moreover, recent laboratory studies of the interaction between Titan's tholins and simulated Titan's surface strongly suggests that many compounds of biological interest, including amino-acids, could be produced on Titan's surface. These new data will be presented together with a general description of Titan's astrobiological aspects as seen from Cassini-Huygens data. References F. Raulin. Astrobiology and habitability of Titan. Space Science Reviews 135, 37-48 (2008) F. Raulin , C. P. McKay , J. I. Lunine and T. Owen. Titan's Astrobiology. In "Titan from Cassini-Huygens" R. Brown, J-P Lebreton H.Waite Eds, Springer, pp. 215-233 (2009) F. Raulin, K. P. Hand, C. P. McKay and M. Viso. Exobiology and planetary protection. In "Moons of the outer solar system: exchange processes involving the interiors", O. Grasset et al. Eds, Space Science Review, in press (Feb. 2010).

Raulin, Francois; Coll, Patrice; Buch, Arnaud; Cloix, Megane; Guan, Yuan Yong; Jerome, Murielle; Poch, Olivier; Ramirez, Sandra I.; Szopa, Cyril; Cottin, Hervé

412

Testing the Ti-in-Zircon Thermometer  

NASA Astrophysics Data System (ADS)

Results of an empirical thermometer based on the concentration of Ti in zircon recently led Watson and Harrison (2005) to propose the existence of wet, minimum melting throughout the Hadean Eon - a hypothesis with far ranging implications. Tests of this hypothesis include: assessment of the range of validity of the thermometer, documentation of crystallization temperatures of post-Hadean granitoid zircons, and replication of the ca. 680°C} peak temperature of Hadean zircons. We have probed the energies of the isovalent substitution of Ti on the Si and Zr sites in zircon using the SIESTA implementation of density functional theory which uses pseudopotentials to describe the core electrons and nuclei, and a numerical scheme to describe valence electrons which allows large numbers of atoms to be assessed. Results show that the substitution of Ti on the Si site is highly favoured over the competing mechanism by approximately 32 kJ/mol. Thus essentially all Ti is expected to occupy the Si site in the zircon crystal structure in the temperature range over which the thermometer has been calibrated thus explaining in part the observed linear behaviour. We have developed a SHRIMP multi-collector protocol for zircon utilizing 49Ti/SiO which yields <0.5% precision for Ti concentrations down to the ppm level. Analysis of zircons from rutile-bearing metmorphic rocks constrained by thermobarometry to have formed between 550 and 800°C} yield calculated temperatures within uncertainty of the known value, further confirming the general validity of the thermometer in that temperature range. Analyses of a variety of granitoids including tonalite yield calculated temperatures ranging up to 820°C} that broadly correlate with zircon saturation temperature. Thus we infer that calculated temperatures of <700°C} from granitoid zircons are generally restricted to water-saturated melting conditions. We have revisited the Hadean zircons of Jack Hills, Western Australia, and more than doubled the number of Ti analyses. Of the 136 total analyses of zircons ranging in age from 3.91-4.35 Ga, only seven yield calculated temperatures in excess of 800°C}. The vast majority of analyses instead plot in a normal distribution with a peak at 680 ± 20°C}. Together with results from other studies (e.g., O isotopes, Lu-Hf, inclusion mineralogy) we conclude that the Hadean Earth supported wet, minimum melting, the formation of clay minerals under ambient conditions, and peraluminous melting of pelitic protoliths. Current analytical developments involve ion imaging Ti concentration variations using 48Ti at high mass resolving power.

Harrison, T. M.; Aikman, A.-; Holden, P.-; Walker, A. M.; McFarlane, C.-; Rubatto, D.-; Watson, E. B.

2005-12-01

413

The methane cycle on Titan  

NASA Astrophysics Data System (ADS)

Saturn's moon Titan is the second largest natural satellite in the solar system, and the only one that possesses a substantial atmosphere. With a surface temperature of 93.7 K at the equator, Titan's water is almost completely frozen out of the atmosphere; water ice comprises between 35% and 45% of the mass of Titan depending on the interior model. But methane seems to play many of the roles on Titan that water does on Earth: clouds have been observed, fluvial and dendritic features have been imaged suggesting episodic heavy rainfall, and there is compelling but circumstantial evidence for near-polar lakes or seas of methane and its atmospheric photochemical product, ethane. However, whereas Earth possesses a massive global ocean of water, Titan lacks a global methane ocean, and on Titan, low-latitude rainfall appears to be an occasional process limited by the small amount of available solar energy compared with that of Earth. Titan is therefore distinct from the Earth, but is also different from Venus in retaining an active cycle of precipitation and evaporation, and from Mars in the preponderance of active fluvial and pluvial processes in the present day.

Lunine, Jonathan I.; Atreya, Sushil K.

2008-03-01

414

Detrital zircon provenance and Ordovician terrane amalgamation  

Microsoft Academic Search

12 13 5300 words, 45 references, 2 tables, 11 figures 14 15 Running title: Detrital zircon provenance, western Ireland 16 17 18 Abstract 19 Detrital-zircon analysis of sandstones interbedded with ca 464 Ma ignimbrites in 20 the lower Mweelrea Formation of the South Mayo Trough, western Ireland, 21 suggests Ordovician source-rock provenance that corresponds to two distinct 22 volcanic-arc phases

Brian McConnell; Quentin G. Crowley

415

Monosodium Titanate Sludge Filtration  

SciTech Connect

Good filterability of tetraphenylborate (TPB) slurry is attributed to the hydrophobic nature of crystalline organic TPB that forms a firm but porous filter cake, allowing salt solution to pass through without unduly compressing the cake. Addition of inorganic sludge or monosodium titanate (MST) has an adverse effect on filtration, but the overall filtration rate with TPB is satisfactory. Poor cross-flow filtration performance for the Salt Disposition Alternatives requiring MST filtration is attributed primarily to the difficulty in filtering the residual inorganic sludge rich in iron and aluminum precipitates. Ferric hydrolysis products and colloids form a bulky and sticky filter cake significantly reducing filtration rate. Similarly poor filtration rates were observed in the BNFL ferric/ferrous precipitation process, necessitating a change to permanganate precipitation. This report, based on a few sludge settling observations, does not resolve the MST/Sludge filterability issue. However, it does identify the need for a change in emphasis from cross-flow optimization to understanding and controlling the chemistry and physics of alkaline inorganic particle suspensions and filterability. Promising potential exists to identify or develop surfactants or flocculants to enhance filterability of SRS sludge and monosodium titanate. Additional work is needed to provide a basic understanding of the nature of caustic sludge filter cake formation.

Dworjanyn, L.O.

2000-11-07

416

Huygens provides insights about Titan  

NASA Astrophysics Data System (ADS)

Huygens provides insights about Titan Following the Huygens probe's successful 14 January soft landing on Titan, Saturn's largest moon, scientists at a 21 January European Space Agency (ESA) news briefing announced that the moon has Earth-like meteorology and geology, and that there is evidence for liquid methane. Martin Tomasko, principal investigator for the Huygens Descent Imager-Spectral Radiometer, said, ``Geological evidence for precipitation, erosion, mechanical abrasion and other fluvial activity says that the physical processes shaping Titan are much the same as those shaping Earth.''

Showstack, Randy

2005-01-01

417

Elevation distribution of Titan’s craters suggests extensive wetlands  

NASA Astrophysics Data System (ADS)

Using a new global topographic map of Titan, we find that craters on Titan preferentially lie at higher than average elevations. We explore several explanations for this observed behavior, and judge the most reasonable explanation to be the presence of widespread wetlands of liquid hydrocarbons at low elevations over much of geologic time. Impacts into a shallow marine environment or a saturated layer of sediments more than several hundred meters thick would produce crater morphologies similar to terrestrial submarine impacts. These are known to lack significant topographic expression, and would thus be difficult to observe with the Cassini spacecraft. Since Titan’s near-surface methane inventory likely fluctuated over geologic time, with episodic delivery and continuous depletion, a few craters at low elevations can nonetheless be expected.

Neish, Catherine; Lorenz, R.

2013-10-01

418

A new concept and first development results of a PZT thin film actuator  

Microsoft Academic Search

High piezoelectric coupling coefficients of PZT-based material systems can be employed for actuator functions in micro-electro-mechanical systems (MEMS) offering displacements and forces which outperform standard solutions. Within this project a stress compensated, PZT coated cantilever concept for a 6\\

M. Hoffinann; H. Kuppers; T. Schneller; U. Bottger; U. Schnakenberg; W. Mokwa; R. Waser

2000-01-01

419

The relationship between the mechanical properties and microstructures of sintered PZT  

Microsoft Academic Search

PZT materials are increasingly being used in infrared sensors, transducers and actuators. The use of these sensor elements require materials with a high degree of reliability and mechanical integrity. In view of the extreme brittleness of PZT materials, there is a need to understand the factors responsible for the poor mechanical properties. Samples in the form of circular discs and

Haitao Huang; Peter Hing

1999-01-01

420

The use of the ultrasonic compaction method for the PZT piezoelectric ceramics fabrication  

Microsoft Academic Search

The method of ultrasonic (US) compaction for the fabrication of Pb(ZrTi)O3 PZT piezoceramics was approved. The values of density, granularity, shrinkage of ceramic samples, sintered from the compacts compacted by traditional uniaxial pressing and by ultrasound action are compared. It is shown that US compaction contributes to sintering temperature lowering and to PZT piezoceramics granularity reduction

O. L. Khasanov; J. S. Lee; Yu. P. Pokholkov; V. M. Sokolov; E. S. Dvilis; M. S. Kim; B. G. An

1999-01-01

421

Carbon isotopic enrichment in Titan's Tholins: implications for Titan's aerosols  

NASA Astrophysics Data System (ADS)

Since the discovery of the main composition of Titan s atmosphere many laboratory experiments have been carried out to mimic its chemical evolution and in particular the formation of the haze particles of this atmosphere Indeed the solid products obtained during these simulation experiments -- often named Titan s tholins -- are supposed to be analogues of Titan s aerosols and many studies have already been achieved on these tholins We have studied the possible isotopic fractionation of carbon during the processes involved in the formation of Titan s tholins using tholins obtained from different simulation experiments We will present the first results obtained on the isotopic ratios of 13 C 12 C measured on the analogues of Titan s aerosols synthesized in laboratory Measurement of delta 13 C leaded both on laboratory aerosols and on the initial gas mixture N 2 CH 4 98 2 used in the simulations doesn t show any evident deficit or enrichment of 13 C in comparison with 12 C in the aerosols synthesised compared to the initial gas mixture Preliminary retrieving of the data of the ACP instrument on the Huygens probe suggests that Titan s aerosols may present also no enrichment This allows us to go further in the analyses of the ACP data in comparison with the first conclusions newly published in Nature Isra e l et al Nature 2005

Nguyen, N.; Raulin, R.; Coll, C.; Derenne, D.; Szopa, S.; Israël, I.; Cernogora, C.; Bernard, B.

422

Fabrication and comparison of PMN-PT single crystal, PZT and PZT-based 1-3 composite ultrasonic transducers for NDE applications.  

PubMed

This paper describes fabrication and comparison of PMN-PT single crystal, PZT, and PZT-based 1-3 composite ultrasonic transducers for NDE applications. As a front matching layer between test material (Austenite stainless steel, SUS316) and piezoelectric materials, alumina ceramics was selected. The appropriate acoustic impedance of the backing materials for each transducer was determined based on the results of KLM model simulation. Prototype ultrasonic transducers with the center frequencies of approximately 2.25 and 5MHz for contact measurement were fabricated and compared to each other. The PMN-PT single crystal ultrasonic transducer shows considerably improved performance in sensitivity over the PZT and PZT-based 1-3 composite ultrasonic transducers. PMID:20580050

Kim, Ki-Bok; Hsu, David K; Ahn, Bongyoung; Kim, Young-Gil; Barnard, Daniel J

2010-04-24

423

The TITAN reversed-field-pinch fusion reactor study  

SciTech Connect

This report discusses research on the titan-1 fusion power core. The major topics covered are: titan-1 fusion-power-core engineering; titan-1 divertor engineering; titan-1 tritium systems; titan-1 safety design and radioactive-waste disposal; and titan-1 maintenance procedures.

Not Available

1990-01-01

424

PZT films deposited by a hydrothermal method and characterizations  

Microsoft Academic Search

Pb(Zr0.52,Ti0.48)O3 (PZT) polycrystalline films were produced by a hydrothermal synthesis on titanium substrates. Autoclaves were put in a sand bath with a temperature lower than 200°C. Hydroxide potassium KOH (4 mol l?1) was used as the mineralizer and Pb(NO3)2, ZrOCl2·8H2O, TiO2 as the precursors. This new hydrothermal treatment is a simplified process of the already reported ones. Results of a

S. Euphrasie; S. Daviero-Minaud; P. Pernod

2003-01-01

425

Effect of substrate bending on the piezoelectric measurement of PZT thin film  

NASA Astrophysics Data System (ADS)

Bonding conditions between PZT thin film and sample holder greatly affect the strain measurement of the PZT sample. The influence of various bonding conditions on the measured displacement were analyzed using finite element analysis (FEA). One-end fixed sample induces the maximum bending displacement. Experiments were performed on sol-gel derived PZT thin film. The voltage-displacement curve and "butterfly" loop were measured using laser Doppler method with phase detection. Experimental results agreed well with the simulated ones. The measured frequency dependence of piezoelectric response of PZT thin film indicated that, if the operating frequency was lower than 2 kHz, good bonding effect could be obtained when the entire back surface of the sample was glued to a rigid supporter using epoxy resin. A simple bonding model which considered the adhesives as a spring was used to estimate the frequency response of PZT thin film sample.

Xu, Xiaohui; Tang, Jianhong; He, Liangna

2009-05-01

426

Corona chemistry in Titan.  

PubMed

The atmosphere of Titan is constantly bombarded by galactic cosmic rays and Saturnian magnetospheric electrons causing the formation of free electrons and primary ions, which are then stabilized by ion cluster formation and charging of aerosols. These charged particles accumulate in drops in cloud regions of the troposphere. Their abundance can substantially increase by friction, fragmentation or collisions during convective activity. Charge separation occurs with help of convection and gravitational settling leading to development of electric fields within the cloud and between the cloud and the ground. Neutralization of these charged particles leads to corona discharges which are characterized by low current densities. We have therefore, experimentally studied the corona discharge of a simulated Titan's atmosphere (10% methane and 2% argon in nitrogen) at 500 Torr and 298 K by GC-FTIR-MS techniques. The main products have been identified as hydrocarbons (ethane, ethyne, ethene, propane, propene+propyne, cyclopropane, butane, 2-methylpropane, 2-methylpropene, n-butane, 2-butene, 2,2-dimethylpropane, 2-methylbutane, 2-methylbutene, n-pentane, 2,2-dimethylbutane, 2-methylpentane, 3-methylpentane, n-hexane, 2,2-dimethylhexane, 2,2-dimethylpentane, 2,2,3-trimethylbutane, 2,3-dimethylpentane and n-heptane), nitriles (hydrogen cyanide, cyanogen, ethanenitrile, propanenitrile, 2-methylpropanenitrile and butanenitrile) and a highly branched hydrocarbon deposit. We present the trends of hydrocarbons and nitriles formation as a function of discharge time in an ample interval and have derived their initial yields of formation. The results clearly demonstrate that a complex organic chemistry can be initiated by corona processes in the lower atmosphere. Although photochemistry and charged particle chemistry occurring in the stratosphere can account for many of the observed hydrocarbon species in Titan, the predicted abundance of ethene is too low by a factor of 10 to 40. While some ethene will be produced by charged-particle chemistry, the production of ethene by corona processes and its subsequent diffusion into the stratosphere appears to be an adequate source. Because little UV penetrates to the lower atmosphere to destroy the molecules formed there, the corona-produced species may be long-lived and contribute significantly to the composition of the lower atmosphere and surface. PMID:11541887

Navarro-Gonzalez, R; Ramirez, S I; Matrajt, G; Basiuk, V; Basiuk, E

1998-06-01

427

Geochemical signatures and magmatic stability of terrestrial impact produced zircon  

NASA Astrophysics Data System (ADS)

Understanding the role of impacts on early Earth has major implications to near surface conditions, but the apparent lack of preserved terrestrial craters > 2 Ga does not allow a direct sampling of such events. Ion microprobe U-Pb ages, REE abundances and Ti-in-zircon thermometry for impact produced zircon are reported here. These results from terrestrial impactites, ranging in age from ~ 35 Ma to ~ 2 Ga, are compared with the detrital Hadean zircon population from Western Australia. Such comparisons may provide the only terrestrial constraints on the role of impacts during the Hadean and early Archean, a time predicted to have a high bolide flux. Ti-in-zircon thermometry indicates an average of 773 °C for impact-produced zircon, ~ 100 °C higher than the average for Hadean zircon crystals. The agreement between whole-rock based zircon saturation temperatures for impactites and Ti-in-zircon thermometry (at aTiO2 = 1) implies that Ti-in-zircon thermometry record actual crystallization temperatures for impact melts. Zircon saturation modeling of Archean crustal rock compositions undergoing thermal excursions associated with the Late Heavy Bombardment predicts equally high zircon crystallization temperatures. The lack of such thermal signatures in the Hadean zircon record implies that impacts were not a dominant mechanism of producing the preserved Hadean detrital zircon record.

Wielicki, Matthew M.; Harrison, T. Mark; Schmitt, Axel K.

2012-03-01

428

Titan's Rotational Light-Curve  

Microsoft Academic Search

Recent observations demonstrate that near-infrared spectroscopy can probe Titan's surface through its haze. In a 5-week period during September and October 1993 we observed Titan's methane windows at 1.1, 1.3, 1.6, and 2 ?m. At 1.1 and 1.3 ?m observations were consistent with observations in 1992 at the same phases reported by Lemmon et al. (1993, Icarus 103, 329-332). Our

Mark T. Lemmon; Erich Karkoschka; Martin Tomasko

1995-01-01

429

Molecular Dynamics Simulation of Disordered Zircon  

SciTech Connect

The melting of zircon and the amorphous state produced by quenching from the melt were simulated by molecular dynamics using a new partial charge model combined with the Ziegler-Biersack-Littmark potential. The model has been established for the description of the crystalline and aperiodic structures of zircon in order to be used for the simulation of displacement cascades. It provides an excellent fit to the structure, and accounts with convenient precision the mechanical and thermodynamic properties of zircon. The calculated melting temperature is about 2100 K. The activation energy for self-diffusion of ions in the liquid state was determined to be 190-200 kJ/mole. Melt quenching was employed to produce two different disordered states with distinct densities and structures. In the high density disordered state, the zircon structure is intact but the bond angle distributions are broader, 4% of the Si units are polymerized, and the volume swelling is about 8%. In the low density amorphous state, the Zr and Si coordination numbers are lower, and the Zr-O and Si-O bond lengths are shorter than corresponding values for the crystal. In addition, a highly polymerized Si network, with average connectivity of two, is observed in the low density amorphous state. These features have all been experimentally observed in natural metamict zircon. The present findings, when considered in light of experimental radiation effects studies, suggest that the swelling in zircon arises initially from disorder in the zircon crystal, and at high doses the disordered crystal is unable to accommodate the volume expansion and transforms to the amorphous state.

Devanathan, Ram; Corrales, Louis R.; Weber, William J.; Chartier, Alain; Meis, Constantin

2004-02-27

430

The TITAN magnet configuration  

SciTech Connect

The TITAN study uses copper-alloy ohmic-heating coils (OHC) to startup inductively a reversed-field-pinch (RFP) fusion reactor. The plasma equilibrium is maintained with a pair of superconducting equilibrium-field coils (EFCs). A second pair of copper EFCs provides the necessary trimming of the equilibrium field during plasma transients. A compact toroidal-field-coil (TFC) set is provided by an integrated blanket/coil (IBC). The IBC concept also is applied to the toroidal-field divertor coils. Steady-state operation is achieved with oscillating-field current drive, which oscillates at low amplitude and frequency the OHCs, EFCs, the TFCs, and divertor coils about their steady-state currents. An integrated magnet design, which uses low-field, low technology coils, and the related design basis is given. 18 refs.

Bathke, C.G.

1987-01-01

431

Mapping Titan's Induced Magnetosphere  

NASA Astrophysics Data System (ADS)

In this work we study the spatial distribution of the magnetic pressure in the vicinity of Titan from all the Cassini flybys to date in an attempt to characterize the average extent and shape of its induced magnetosphere at altitudes above 950 km. The role of parameters such as Saturn Local Time (SLT), total upstream pressure, and convective electric field is studied. Then we combine Cassini magnetometer (MAG), Plasma Spectrometer (CAPS), Plasma Wave/Langmuir probe (RPWS/LP), and Magnetospheric Imager (MIMI) observations in order to compare, when possible, the magnitudes of the dynamic, magnetic and plasma pressures at different altitudes. Finally, we discuss the constraints that these results set for the current theoretical models.

Bertucci, C.; Achilleos, N.; Szego, K.; Wahlund, J. E.; Modolo, R.; Sittler, E. C.; Coates, A. J.; Garnier, P.; Dandouras, I.; Ma, Y.; Crary, F.; Young, D.

2008-12-01

432

Nondestructive testing of ferroelectrics by thermal wave methods  

NASA Astrophysics Data System (ADS)

The application of thermal wave measurement techniques was demonstrated for Strontium Barium Niobate (SBN) and Lithium Tantalate (LT) crystals, Lead Zirconate Titanate (PZT) ceramics, and PZT thin films. We have investigated the influence of poling conditions and of chromium and cerium doping on the polarization distribution and domain wall pinning in SBN crystals, the impact of ion beam etching on the polarization distribution in high-detectivity LT infrared sensors, the influence of poling procedure on the polarization distribution of PZT piezoceramics, and the polarization distribution in self-polarized PZT thin films.

Gerlach, Gerald; Suchaneck, Gunnar; Movchikova, Alena; Malyshkina, Olga

2007-03-01

433

Poling process optimization of piezo nano composite PZT/polimer  

NASA Astrophysics Data System (ADS)

The objective of poling process is to make the electric dipole directions to be parallel in the inside perovskite crystal of piezo materials. In simply way, poling was carried out by giving the two sides of a piezo material by highly electrical potential. More parallel of electrical dipoles, it is more strength the piezo characteristics. The optimization involved control of temperature, time depth and the electrical voltage. The samples was prepared by solgel method with precursor tetrabutyl titanat Ti(OC4H9)4, zirconium nitrat Zr(NO3)4.5H2O, Pb(CH3COO)2.3H2O and solution ethylene glycol. Molar ratio Pb:Zr:Ti = 1,1:0,52:0,48 with concidering lossed Pb. Result of solgel process is nano powder PZT. The formed nano powder PZT was then mixed with polimer PVDF and pressed 10 MPa at 150 °C with the size 15 mm in diameter. After poling, piezoelectric constant d33 was measured. The highest d33 = 45 pC/N was found at poling parameters V = 5 kV/ mm, T = 120 °C dan time depth = 1 hours.

Ridlo, M. Rosyid; Lestari, Titik; Mardiyanto; Oemry, Achiar

2013-09-01

434

Tuning of sol-gel derived PZT MEMS resonators  

NASA Astrophysics Data System (ADS)

This paper demonstrates the tunability of resonant frequencies for MEMS piezoelectric resonators acting in the d33 mode by experiment and theoretical analysis. Thin-film MEMS beams made by sol-gel PZT processing are first fabricated and tested to investigate the tuning capability. The three-layered interdigitated-electrode trapezoidal beams are then modeled by finite element analysis for validation. Beam curl and undercutting are also examined to present an alternative way of finding the stress gradient in comparison to Stoney's formula. The experimental and analytical results indicate that piezoelectric MEMS resonators have the ability to passively tune their resonant frequencies between open-circuit and short-circuit frequencies. Tuning of 0.2-0.6% is demonstrated experimentally, which compares with finite element predictions of 1.02-1.08%. Consideration is given to the reason for the differences in experimental percentages versus those predicted numerically, including the use of bulk PZT values in the ANSYS simulations, the undercut and curling effects of fabrication, and the low percentage of piezoelectric poling in the length direction.

Knight, Ryan R.; Frederick, Amanda A.; Mo, Changki; Clark, William W.

2010-12-01

435

Piezoelectric micromachined ultrasonic transducers based on PZT thin films.  

PubMed

This paper describes fabrication and characterization results of piezoelectric micromachined ultrasonic transducers (pMUTs) based on 2-microm-thick Pb(Zr0.53Ti0.47O3) (PZT) thin films. The applied structures are circular plates held at four bridges, thus partially unclamped. A simple analytical model for the fully clamped structure is used as a reference to optimize design parameters such as thickness relations and electrodes, and to provide approximate predictions for coupling coefficients related to previously determined thin film properties. The best coupling coefficient was achieved with a 270-microm plate and amounted to kappa2 = 5.3%. This value compares well with the calculated value based on measured small signal dielectric (epsilon = 1050) and piezoelectric (e3l,f = 15 Cm(-2)) properties of the PZT thin film at 100 kV/cm dc bias. The resonances show relatively large Q-factors, which can be partially explained by the small diameters as compared to the sound wavelength in air and in the test liquid (Fluorinert 77). A transmit-receive experiment with two quasi-identical pMUTs was performed showing significant signal transmission up to a distance of 20 cm in air and 2 cm in the test liquid. PMID:16463493

Muralt, Paul; Ledermann, Nicolas; Baborowski, Jacek; Barzegar, Abdolghaffar; Gentil, Sandrine; Belgacem, Brahim; Petitgrand, Sylvain; Bosseboeuf, Alain; Setter, Nava

2005-12-01

436

Synthesis of PZT powder by conventional method at various conditions  

NASA Astrophysics Data System (ADS)

In this work, the formation of Pb(Zr1-xTix)O3 solid solutions with composition near the morphotropic phase boundary (MPB) using the conventional ceramic method have been studied by changing the thermal conditions such as temperature ramp rate and isothermal times during the calcination treatment performed between 700 and 900 °C. The perovskite phase formation and morphology of undoped Pb(Zr0.52Ti0.48)O3 (abbreviated PZT) and doped new material Pb0.98Gd0.02[(Zr0.52Ti0.48)0.98 (Mg1/3Nb2/3)0.01 (Ni1/3Sb2/3)0.01]O3 (abbreviated PZT-PGMNNS) specimens have been examined by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier Transform Infrared (FTIR) while the thermal evolution of the initial precursor was followed by TG-DTA. So the results of these studies have been discussed.

Necira, Z.; Boutarfaia, A.; Abba, M.; Abdessalem, N.

2012-06-01

437

Crack detection in a beam using PZT sensors  

NASA Astrophysics Data System (ADS)

This paper proposes a method to detect the size and location of an edge-normal crack in a beam-like component by fixing discrete PZT patches at its top and bottom edges. Both theoretical and experimental results are presented. The beam geometry conforms to that of a simply supported beam. Theoretical studies were carried out using the boundary element method (BEM). Variations in the voltage drop in the patches with various crack sizes and positions were obtained theoretically. These results were fitted into a surface. Some of these results were verified by experiments. The inverse problem was also solved. Both the crack size and position were predicted from the voltage drop recorded experimentally by a pair of PZT patches. The maximum errors in the prediction were 9.33% and 4.95% respectively. Cracks as small as 3% of the beam depth can be detected. The response of a sensor is only significant when the distance between a crack and a patch along the edge is approximately less than the depth of the beam. Based on studies with distributed patches, a possible scheme for detecting a crack located anywhere over the entire span of a beam is presented.

Sumant, P. S.; Maiti, S. K.

2006-06-01

438

Titan's Geology as Viewed by the Cassini Titan Radar Mapper  

NASA Astrophysics Data System (ADS)

Cassini's Titan Radar Mapper has imaged the surface of Titan on 8 flybys to date, collecting Synthetic Aperture Radar (SAR) data at spatial resolution ranging from about 300 m to about 2 km. These radar images reveal that Titan's surface has been modified by both endogenic (volcanism, tectonism) and exogenic (impact cratering, erosion) processes, with no process dominating in an obvious way. Although less than 15 % of the surface of Titan has been imaged to date using SAR, the acquired swaths are distributed over a wide latitudinal and longitudinal range, enabling some conclusions to be drawn about the global distribution of processes. Cryovolcanic units have been identified in SAR images mostly at mid-latitudes (40-60 N), these include the construct Ganesa Macula, several calderas with associated flows, and large cryovolcanic flows. Flybys over high northern latitudes have shown lacustrine features, the distribution of these features is consistent with colder temperatures and more precipitation at high latitudes. Some of the depressions filled by the lakes may be volcanic calderas, but a thermokarstic origin is also possible (Mitchell et al., Lunar Planet Sci. Conf. XXXVIII, 2007). Ridges and mountains that are interpreted to be of tectonic origin have been seen mostly at low latitudes (Radebaugh et al., Lunar Planet Sci. Conf. XXXVIII, 2007), while drainage channels appear common at all latitudes (Lorenz et al., Plan. Space Sci., submitted). Fields of dunes (Titan's "sand seas") are mostly equatorial, but a few isolated patches of dunes extend as far north as ~60 degrees. The distribution and orientation of dunes is as expected from Titan's winds (Lorenz et al., 2006, Science 312; Radebaugh et al., Icarus, submitted). Erosion by fluvial processes is likely to have occurred on a global scale. The small number of definitive impact craters suggests that these geologic processes are erasing or burying the majority of impacts. Future data will allow us to further constrain the distribution of tectonism and volcanism, providing valuable input for models of Titan's interior.

Lopes, R. M.; Stofan, E. R.; Wood, C.; Robshaw, L.; Mitchell, K. L.; Radebaugh, J.; Lorenz, R.; Lunine, J.; Wall, S. D.; Kirk, R.; Cassini RADAR Team

2007-05-01

439