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1
Marshall, J. M. « Thin lead zirconate titanate films ». Thesis, Cranfield University, 2006. http://dspace.lib.cranfield.ac.uk/handle/1826/10743.
Texte intégralRésumé :
The
subject of study was the growth and nucleation of sol-gel deposited lead
zirconate titanate
(PZT) films of composition Pb(Zr0_52,Ti0_4g)O3 (PZT52/48). This
particular composition is on a phase boundary between titanium-rich tetragonally
structured PZT and the zirconium-rich rhombohedral phase. The coexistence and relative
instability of these phases is thought to be one of the origins of high piezoelectric
coefficients exhibited
by films of this composition.
The aims of this
study were to investigate variables affecting the piezoelectric
coefficients in
sol-gel deposited PZT52/48 thin films. Control of preferred orientation if
PZT52/48 films on
platinum-coated substrates was accomplished by manipulating
processing conditions, specifically pyrolysis temperature.
Corona
poling was investigated as an alternative to contact poling. Attempts were
made to find a set of
poling parameters which yielded consistent results. Piezoelectric
coefficients are
highly dependant on poling conditions, with coefficient being lower in
insufficiently poled films or those damaged by field induced sample cracking. It was
observed that
(001)/(100)-oriented samples with small grains had significantly lower
piezoelectric coefficients and were harder to pole than coarser-grained (00l)/(l00)-
oriented
samples. Samples with a more irregular grain structure and a wide distribution of
grain size had the lowest piezoelectric coefficients, irrespective of preferred orientation.
The
impact of grain size on piezoelectric coefficients was confirmed using the FWHM of
the
(200) reaction. Films with more irregular grain structures had higher FWHM than
those with more uniform
grains and had lower d33,f and e31,f.
Values of e31,f and d33f were plotted against (001) intensity a determined from xray
diffraction. It was difficult to determine any correlation between piezoelectric
coefficients and
(001) intensity. I comparison, there was a definite inverse correlation
between
d33,f, e31,f and FWHM, indicating that defect concentration has much more of an
impact on piezoelectric coefficients in polycrystalline thin films than (001) intensity as a
result of defect-induced domain
pinning.
2
Williams, C. P. « Synthesis of lead zirconate titanate powders ». Thesis, Cranfield University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268127.
Texte intégral
3
Mohammadabadi, Ali Shafiei. « Hydrogen‐induced damage of lead‐zirconate‐titanate (PZT) ». Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44320.
Texte intégralRésumé :
Lead-Zirconate-Titanate Pb(Zr,Ti)O₃ (PZT) based actuators are evaluated by automotive industry for advanced fuel-injection systems, including hydrogen injection. However, hydrogen can have deleterious effect on the PZT's functionality and properties. The general objective of this work is to study the interactions between PZT and hydrogen. The results of long-term (200-1200 hours) high-pressure (10 MPa) hydrogen exposure on the PZT microstructure show that hydrogen has only superficial effects on the microstructure of bare PZT. However, when an electrode is attached to PZT, the hydrogen damage increased; a porous layer developed immediately adjacent to the electrodes on the PZT surface due to hydrogen spillover. The kinetics of the PZT structural modifications due to hydrogen was investigated by online monitoring of the electrical properties of PZT above the Curie temperature, up to 650°C. The results show that the structural changes can be described by the classical nucleation and growth theory. The growth of the new structure appears to be limited by the diffusion of protons into PZT, with a calculated activation energy of 0.44± 0.09 eV, at 450-650°C. Two relaxation peaks were observed in the dissipation factor curves of the hydrogen-treated PZT. While the kinetics of one of the relaxation peaks obeys the classical Arrhenius law with the activation energy of 0.66 eV, the other peak shows an unusual relaxation kinetic. The mechanisms for the formation of these relaxation peaks are determined. Low temperature (20°C) diffusion of hydrogen into the PZT was also studied, using the water electrolysis technique. Based on the microstructural observations, the diffusion coefficient of hydrogen in PZT was calculated as 9×10-¹¹ cm²/sec. The Maxwell-Wagner polarization mechanism is determined to be responsible for the changes in the hydrogen-affected PZT capacitance. In the last part of the project, alumina coatings were applied to PZT plates using the sol-gel technique, to explore the possibilities of decreasing H₂ damage to PZT. The functionality of the coating against hydrogen damage was evaluated by the water electrolysis technique. Significant decrease of hydrogen damage was observed even for highly porous coatings. The mechanisms by which the alumina coating decreases the hydrogen damage were tentatively proposed.
4
Bathurst, Stephen 1980. « Direct printing of lead zirconate titanate thin films ». Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/43136.
Texte intégralRésumé :
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references (leaves 42-44).
Thus far, use of lead zirconate titanate (PZT) in MEMS has been limited due to the lack of process compatibility with existing MEMS manufacturing techniques. Direct printing of thin films eliminates the need for photolithographic patterning and etching, as well as allows for controlled deposition over non-planar topographies which cannot be accomplished with conventional spin coating processes. This thesis reports the optimal conditions of deposition and crystallization for high dielectric quality PZT thin films via thermal ink jet printing. Included are details of the solution chemistry developed, printing conditions required for MEMS quality films, and thermal processing parameters that enable a strong piezoelectric response.
by Stephen P. Bathurst.
S.M.
5
Bernal, Ashley Lynn. « Lead zirconate titanate nanotubes processed via soft template infiltration ». Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/45886.
Texte intégralRésumé :
Nanoscale ferroelectric materials have numerous possible applications such as actively tunable photonic crystals, terahertz emitters, ultrasound transducers, and energy harvesters. One of most technologically relevant ferroelectric materials is lead zirconate titanate (PZT) due to its large piezoelectric response. However, there are limited methods currently available for creating nanoscale PZT structures. Current top-down patterning methods include material removal via a high energy beam, which damages the piezoelectric's properties, and wet etching, which is an isotropic process that results in poor edge definition. Similarly, current bottom-up approaches such as hard template-growth and hydrothermal processing have limited control over the aspect ratio of the structures produced and lack site specific registry.
In this work, a bottom-up approach for creating PbZr₀.₅₂Ti₀.₄₈O₃ nanotubes was developed using soft-template infiltration by a sol-gel solution. This method allows excellent control of the structures produced, overcoming current manufacturing limitations. PZT nanotubes were fabricated with diameters ranging from 100 to 200 nm, aspect ratios (height to diameter) from 1.25:1 to 5:1, and wall thicknesses from 5 to 25 nm. The piezoelectric and ferroelectric nature of the nanotubes was characterized via scanning probe microscopy in order to investigate nanoscale phenomena. Specifically, the effects of lateral constraint, substrate clamping, and critical size on the extrinsic contribution to the piezoelectric response were studied and the results are discussed.
6
Braun, Wolfgang. « Study of lead zirconate titanate films grown by MOCVD ». Thesis, Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/30420.
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7
Verdier, Cyril [Verfasser]. « Fatigue Effects in Bulk Lead-Zirconate-Titanate / Cyril Verdier ». Aachen : Shaker, 2004. http://d-nb.info/1170545076/34.
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8
Navarro, A. « Fabrication of lead zirconate titanate ceramics for pyroelectric applications ». Thesis, Cranfield University, 2001. http://dspace.lib.cranfield.ac.uk/handle/1826/11244.
Texte intégralRésumé :
The objective of this work was twofold, i.e. to develop an aqueous route for tape casting Lead Ziconate Titanate (PZT)ceramics for pyroelectric applications and to optimise the die-pressing route for reducing defect size and number in bulk Lead Zicronate Titanate ceramics (PZT).
9
He, Hui. « Phase transitions in Sn-modified lead zirconate titanate antiferroelectric ceramics ». [Ames, Iowa : Iowa State University], 2007.
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10
Cordero, Cabrera Mario César. « Sol-gel processing and fabrication of lead zirconate titanate ceramics ». Thesis, University of Cambridge, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.615260.
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11
Dutta, Indrajit. « Electro-Mechanical Behavior of Strontium Modified Lead Zirconate Titanate Ceramics ». University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1187036967.
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12
Xuqian, Zheng. « Lead Zirconate Titanate Piezoelectric Cantilevers for Multimode Vibrating Microelectromechanical Systems ». Case Western Reserve University School of Graduate Studies / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=case1428592535.
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13
Thomas, James A. « Optical phased array beam deflection using lead lanthanum zirconate titanate / ». Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1998. http://wwwlib.umi.com/cr/ucsd/fullcit?p9907669.
Texte intégral
14
Sun, D. « Deposition-patterning of lead zirconate titanate (PZT) using electrohydrodynamic atomization ». Thesis, University College London (University of London), 2008. http://discovery.ucl.ac.uk/1445863/.
Texte intégralRésumé :
This research develops a novel processing technique, namely electrohydrodynamic atomization, for forming lead zirconate titantate (PZT) in various structures. The capability to process PZT materials is crucial due to the demand in applications of sensors, capacitors and actuators. Structures from continuous films to columnar structures and track-structures need to be fabricated with high effectiveness, low cost and high accuracy. This study focused on investigating a new deposition-patterning technique to fabricate such versatile material. Electrohydrodynamic atomization is a novel processing technique which makes use of electric field induced flow (electrohydrodynamics) to deposit and pattern pre-designed structures. This research is comprised of three parts. In the first part, the properties of 0.6 mol/L PZT sol was studied, which include density, electrical conductivity, viscosity and surface tension. Then the sol was placed in a furnace and heat-treated and the ideal sintering temperature was determined. After that, the electrohydrodynamic atomization process was successfully utilized for spraying 0.6 mol/L PZT sol in the cone-jet mode. Important spraying parameters such as applied voltage, flow rate and distance between the needle and substrate were examined. The mode selection map for this sol was constructed from 5x10"'2 m3 s"1 up to the critical flow rate point above which the cone-jet mode is not obtainable. The PZT particles were deposited on metallic substrates and heat-treated at 650 °C. Microstructure of the deposit was studied. Nano-structured PZT particles were observed under the microscope and the average size of these spherical particles was approximately 100nm. Secondly, the influence of concentration of sprayed sol on the as-deposited structures was investigated. Continuous PZT films were obtained using 0.06 mol/L sols while columnar PZT structures which are used to form 1-3 composites were produced using 0.6 mol/L sols. The reason for this feature was discussed considering the droplets of different sizes and their evaporation. The growth of PZT columns was studied by observing the cross-sectional structures at 10s, 20s, 40s, 60s, 180s and 330s. The affect of substrate temperature on the columnar structure was also analyzed by studying the density of the columns. A 1-3 composite was produced by infiltrating photoresists into columnar structures. The dielectric properties of such composite and the continuous film were investigated. Thirdly, PZT track-structures were produced by electrohydrodynamic printing. Cracks within the printed structures were eliminated by adding polyvinylpyrrolidone (PVP) to 0.6 mol/L PZT sol. Different volume ratios from 1:1 to 1:4 were used when mixing PZT and PVP solutions. The microstructure of the PZT tracks printed using different solutions were investigated using optical microscope. The content of residual PVP polymer was examined and it elucidated that PVP was completely removed after heat treatment at 650 °C.
15
Waring, Miles Alexander Thomas. « The electrical and structural properties of lanthanum-doped lead zirconate titanate ». Thesis, University of Oxford, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491614.
Texte intégralRésumé :
The literature shows there is confusion regarding the factors that control the electrical properties and observed lattice response of PLZT. This study aims to characterise the electrical properties and study the lattice response of PLZT to help resolve these issues. Powders with varying compositions were produced by the mixed oxide process. A range of specimen grain sizes was produced by varying the temperature and hold time during pressure-less sintering. Lanthanum affects the grain growth and diffusion rate, changing the grain size, density and reducing the axial ratio. Strain and polarisation hysteresis, d33 , and permittivity with temperature were all measured. Lanthanum increases the d33 value and reduces the Curie temperature and coercive field strength. However, the results show that grain size and axial ratio also alter these properties. The lattice response was determined using neutron diffraction. Specific planes' lattice spacings, in different spatial directions, were measured by re-orientating the specimens relative to the neutron beam. The spacing of these planes was found to vary with applied field, as a result of the converse-piezoelectric effect, and clastic misfit strains resulting from domain reorientation in surrounding grains. Lattice strain in the nonpolar direction larger than that in the polar direction was observed, along with a small tensile lattice strain in the polar direction after poling. The large strain in the non-polar direction is attributed to elastic misfit strains, but an additional voltageinduced strain was found in that direction, potentially a result of the elastic misfit strain distorting the lattice and allowing the polarisation to align with the field. The tensile poling strain result is explained by a change in the crystal structure, or by considering elastic misfit strains between neighbouring domains. This study has discussed the factors affecting the macroscopic piezoelectric properties, and contributed to the understanding of the underlying lattice response. Supplied by The British Library - 'The world's knowledge'
16
Bortolani, Francesca. « Synthesis and development of lead zirconate titanate inks for direct writing ». Thesis, Cranfield University, 2010. http://dspace.lib.cranfield.ac.uk/handle/1826/4456.
Texte intégralRésumé :
The work presented in this thesis is focused on the development of a novel low processing temperature PZT (lead zirconate titanate) ink for direct writing of functional microsystems. The work examines both the synthesis of PZT powder for use in the ink as well as the formulation of the ink. Two different routes were investigated for the powder synthesis: electro hydrodynamic atomisation (EHDA) and molten salt synthesis (MSS). EHDA is a technique that leads to the formation of small and spherical droplets that, after drying, result in solid particles. Several process parameters were investigated in order to determine their influence on particle size. PZT sols with concentrations up to 0.6 M were electrosprayed under different conditions: the flow rate was varied from 0.2 to 0.6 ml h1 and the distance between the needle and the bottom electrode was increased from 20 to 40 mm. The solvent was dried by the use of a focused lamp with temperature between 200 and 680oC. It was determined that, in order to reduce the size of the PZT particles, low concentration and low flow rate were needed. The needle-electrode distance was found not to have a strong effect on size. However an increase in the focus temperature to a threshold of 520oC led to a reduction of the particle diameter. A further increase of the degree of heating led to the formation of big and irregular particles. Small PZT particles with diameter of 260 nm were obtained under the following conditions: flow rate of 0.2 ml h1, sol concentration of 0.2 M, needle-electrode distance of 30 mm and drying temperature of 520oC. The synthesised powder was spherical in shape, that made it suitable for IJP, but the yield was very low. In order to overcome the problem associated with the low yield of EHDA, MSS was investigated. Also in this case process parameters were studied with the purpose to reduce particle size. The optimum synthesis conditions were found to be 1 hour at 850oC, with a ramp rate of 3.3oC min1. Under these circumstances, PZT particles with a mean diameter of 340 nm were synthesised. From the investigation it came to light that long times and higher temperatures led to an increase in particle size due to coarsening process. Short times and low temperatures led instead to an incomplete reaction between the starting oxides. A reaction mechanism for the formation of PZT is also proposed: fully dissolved Pb reacts with the insoluble TiO2 to form PbTiO3. Then ZrO2 reacts with PT and the remaining Pb to form PZT. Composite inks were formulated from the powders synthesised by both the routes. In the case of EHDA however the formulation was hampered due to a low amount of powder available. This resulted in a quick powder sedimentation that led to nozzle clogging during printing. Inks composed of MSS powder were formulated with different solid loadings to identify under which conditions the nozzles were clogging. Two different patterns were printed on the substrate: a 20x20 drops for the identification of the ink behaviour on the wafer, and a line array pattern to determine in which conditions printing quality was enhanced.
17
Zheng, Hong. « Structure-property relations in Sr, Nb, Ba doped lead zirconate titanate ». Thesis, University of Sheffield, 2002. http://etheses.whiterose.ac.uk/14843/.
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18
Akella, Sriram. « Design and test of lead-zirconate-titanate flexural plate wave based actuators ». [Tampa, Fla.] : University of South Florida, 2005. http://purl.fcla.edu/fcla/etd/SFE0001001.
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19
Zai, Marvin Ho-Ming. « Chemical synthesis of lead zirconate titanate thin films for a piezoelectric actuator ». Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367760.
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20
Su, Bo. « Novel fabrication processing for improved lead zirconate titanate (PZT) ferroelectric ceramic materials ». Thesis, University of Birmingham, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.668338.
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21
Yu, Yongjian. « FIELD INDUCED ANTIFERROELECTRIC PHASE SWITICHING BEHAVIOR IN LEAD STRONTIUM ZIRCONATE TITANATE CERAMICS ». University of Cincinnati / OhioLINK, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=ucin971277493.
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22
Lee, Sungchul. « Characterization of lead zirconate titanate (PZT) thin films for ferroelectric memory applications ». Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186318.
Texte intégralRésumé :
Recently, significant progress has been made in integrating ferroelectric materials and semiconductor technology to achieve high density, semiconductor memories. The hysteresis behavior of the polarization versus the electric field and high dielectric constant of ferroelectric materials are useful for non-volatile and dynamic random access memories (DRAMs), respectively. Lead Zirconate-Titanate (Pb(Zr,Ti)O₃), commonly called PZT, is considered to be potentially important in memory applications. PZT is the ferroelectric material studied here. In this dissertation, the measurement methods for polarization and current-voltage characteristics of ferroelectric thin films are investigated. A new method for measuring current-voltage characteristics of ferroelectric materials is developed to distinguish the leakage current from the switching current. Further, the reliability concerns for ferroelectric memories, such as fatigue, retention, and temperature effect, are discussed based on the polarization and leakage-current characteristics of sol-gel derived PZT thin films. In addition to the studies on the charge storage capability, a model of the ferroelectric thin films is presented. Considering the spontaneous polarization of the ferroelectric film, a back-to-back Schottky barrier system having asymmetric barriers is proposed as a model for the platinum-PZT-platinum capacitor. The potential and electric field distributions in PZT thin films are calculated by solving Poisson's equation numerically for different doping concentrations. In this analysis, the permittivity variation with respect to the electric field is considered. Based on these numerical results, capacitance-voltage characteristics of the PZT thin film capacitor are predicted. For a doping concentration of 1 x 10¹⁸ cm⁻³ and the maximum relative permittivity of ∼8000, the calculated C-V curve fits well with the experimental result.
23
Wu, Zhigang. « First-principles calculations of piezoelectricity and polarization rotation in lead zirconate titanate ». W&M ScholarWorks, 2002. https://scholarworks.wm.edu/etd/1539623401.
Texte intégralRésumé :
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.
24
Piekarski, Brett Harold. « Lead zirconate titanate thin films for piezoelectric actuation and sensing of mems resonators ». College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/3195.
Texte intégralRésumé :
Thesis (Ph. D.) -- University of Maryland, College Park, 2005.Thesis research directed by: Mechanical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
25
Imlao, Soodkhet Bond Materials Science & Engineering Faculty of Science UNSW. « Ferroelastic domain switching behaviour in lead zirconate titanate under mechanical and electrical loading ». Awarded by:University of New South Wales. Materials Science & ; Engineering, 2008. http://handle.unsw.edu.au/1959.4/41549.
Texte intégralRésumé :
In this thesis, ferroelastic domain switching behaviour of lead zirconate titanate ceramics, as used in devices such as actuators, was studied. In particular, the effect of cyclic frequency and amplitude were assessed to develop a correlation between macrostructural changes and fatigue behaviour, both in the bulk and in crack-tip process zones. A variety of experimental methods were used. Raman scattering enabled the poling state of the ceramics can be determined. However, it could not distinguish between the different preferred orientations of in-plane c-domains. Conversely, neutron and X-ray diffraction technique can detect domain orientation distribution and the preferred direction of c-domains. In this study, neutron diffraction was used to probe domain switching behaviour in bulk samples while high spatial resolution X-rays were employed to analyse a switching zone near a crack tip. Under cyclic mechanical loading, domain switching and the accumulation of ferroelastic strain becomes saturated with increasing number of cycles. Moreover, time-dependent deformation was investigated. The results show that a domain forward-switching process occurs during creep deformation while a domain backward-switching process takes place during recovery. In addition, it was found that the frequency of applied stress affects the saturation of the ferroelastic strain while its magnitude has an influence on the level of strain accumulated. Under static mechanical loading, it was found that the size of the crack-tip zone where stress-induced domain switching occurs with increase in the stress intensity factor but the degree of domain switching around the crack tip changes only slightly. Under cyclic electrical loading, the results present a strong link between the frequency of the applied field, remnant polarisation, domain switching and the resultant crack growth. The results show that polarisation fatigue, the size of the switching zone, and the crack growth rate is greater at lower loading frequency. The quantitative analysis of the time dependent mechanism as well as the effect of loading frequency and amplitude on domain switching was achieved by applying viscoelastic models. Importantly, these models can be used to explain domain switching behaviour and domain wall movement under cyclic loading and link these processes to macroscopic deformation.
26
Wallace, Jack Bruce. « The effect of surface reduction on the piezoelectric properties of lead zirconate titanate ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0010/NQ40293.pdf.
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Bhattacharya, Mayukh. « Degradation in lead zirconate titanate thin film capacitors for non-volatile memory applications ». Thesis, Virginia Tech, 1994. http://hdl.handle.net/10919/44583.
Texte intégralRésumé :
A study of the degradation of ferroelectric properties in Lead Zirconate Titanate (PZT) thin film capacitors is presented in this work. Metal- Ferroelectric - Metal capacitors were prepared by sputtering and metal organic decomposition (MOD) techniques. Samples with several different film thicknesses were considered in this study. Depolarization, leading to imprint has been studied at various temperatures. Changes in the dielectric properties of the capacitors as a function of the number of fatigue cycles is presented.
Impedance and modulus spectroscopic techniques have been applied to study the effect of degradation on the ferroelectric thin film. It has been shown that with accurate low frequency impedance measurement equipment, new insight can be gained on the mechanisms of degradation in ferroelectric capacitors.Master of Science
28
Chang, Jhing-Fang. « Preparation and characterization of doped lead zirconate titanate Pb(Zrx̳Ti1̳-x)O3̳ films / ». This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-05042010-020142/.
Texte intégralRésumé :
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992.Vita. "x̳", "1̳-x", and "3̳" are subscripts. Abstract. Includes bibliographical references (leaves 120-128). Also available via the Internet.
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Bhattcharya, Mayukh. « Degradation in lead zirconate titanate thin film capacitors for non-volatile memory applications / ». This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-09052009-040636/.
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Teowee, Gimtong. « Electrical and optical characterization of wet chemically derived lead zirconate titanate thin films ». Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/186081.
Texte intégralRésumé :
The present investigation is concerned with the preparation and characterization of sol-gel derived lead zircon ate titanate (PZT) powders and films. Particular emphasis is placed on the synthesis, processing and characterization of thin films. The chemistry employed involves the use of alkoxides of Ti/Zr and lead acetate trihydrate. PZT gels were prepared and characterized insights gained were used as the basis for the synthesis and characterization of thin films. A model was also proposed to augment further understanding of the PZT capacitors obtained. PZT thin films were successfully prepared on various substrates such as platinized Si wafers and Corning 7059 glass. Numerous electrical and optical characterizations were performed, namely dielectric constant and loss, hysteresis loop, switching, fatigue, aging, leakage currents, refractive index, UV transmission spectroscopy, second harmonic generation (SHG) and waveguide loss. These electrical and optical properties are discussed in conjunction with film microstructure and phase assemblage. Very high quality films were obtained (e.g., dielectric constant as high as 3000 at 1kHz, and fatigue-free beyond 10⁸ cycles and optical loss as low as 1.1 dB/em). Aging of these films can be kept as low as l%/decade. It was found that the domains play an important role in determining the dielectric properties. A model of the Pt-PZT-Pt capacitor was successfully developed based on totally depleted back-to-back Schottky barriers and the model predictions agree extremely well with measured device characteristics. This model also explains the different dielectric behaviours of FE films compared to those of bulk ceramics. By tailoring the chemistry and controlling the post-deposition processing conditions and hence microstructures, the properties (both electrical and optical) of the PZT films can be effectively engineered.
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Sriram, Sharath, et sharath sriram@gmail com. « Deposition, Characterisation, and Piezoelectric Response Estimation of Strontium-doped Lead Zirconate Titanate Thin Films ». RMIT University. Electrical and Computer Engineering, 2009. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20090507.144751.
Texte intégralRésumé :
Lead zirconate titanate (PZT), in the form of both bulk and thin films, is used in most piezoelectric applications due to its high piezoelectric response coefficients. Strontium-doped lead zirconate titanate (PSZT) has shown improved piezoelectric response characteristics in bulk form. This work investigates the deposition and characterisation of PSZT in the form of thin films, and reports on results from the estimation of the piezoelectric response of these thin films using two new techniques. The influence of RF magnetron sputter deposition parameters on the composition and orientation of PSZT thin films has been studied. Investigation of the consequence of varying the oxygen partial pressure during deposition on thin film stoichiometry, the influence of the choice of metal-coated silicon substrates on thin film orientation, and the effect of post-deposition cooling rate have been used to identify optimal deposition conditions. The existence of a modified unit cell resulting from these deposition parameters has been verified, and the resulting lattice parameters were estimated. Extensive materials characterisation (using microscopy, diffraction, and spectroscopy) of the PSZT thin films deposited on gold and platinum coated silicon substrates is reported. The limited techniques available for quantitative estimation of d33 for piezoelectric thin films initiated an investigation into alternative possibilities, as a consequence of which two new techniques for piezoelectric coefficient estimation, under the inverse piezoelectric effect, have been developed. One technique capitalises on the measurement accuracy of the nanoindenter in following thin film displacement, while the other uses a standard atomic force microscope in contact imaging mode to estimate d33. The development, scope, and limitations of both techniques are discussed. The techniques developed have been used to estimate the piezoelectric response of PSZT thin films. Depending on the thin film deposition parameters and the analysis frequency, values of piezoelectric response higher than any measured for thin films on silicon have been estimated. PSZT thin films deposited on gold-coated silicon at low deposition temperatures resulted in d33 values up to 892 pm/V. The study of the piezoelectric response in the millihertz frequency regime resulted in colossal values (ranging in tens of thousands of pm/V) for PSZT thin films deposited at high temperatures on platinum-coated silicon. This was hypothesised to be a result of enhanced ferroelastic domain switching. This hypothesis was verified by reducing the clamping on domains by synthesising island-structured PSZT films and obtaining an increased piezoelectric response.
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Matichyn, Serhiy. « Fabrication and characterisation of ferroelectric lead zirconate titanate and strontium bismuth tantalate thin films ». [S.l.] : [s.n.], 2006. http://diglib.uni-magdeburg.de/Dissertationen/2006/sermatichyn.htm.
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Song, Yoon-Jong. « Ferroelectric Thin Films for High Density Non-volatile Memories ». Diss., Virginia Tech, 1998. http://hdl.handle.net/10919/30675.
Texte intégralRésumé :
Ferroelectric random access memories (FRAM) are considered as future memories due to high speed, low cost, low power, excellent radiation hardness, nonvolatility, and good compatibility with the existing integrated circuit (IC) technology. The non-volatile FRAM devices are divided into two categories, based on reading technique: destructive readout (DRO) FRAM and non-destructive readout (NDRO) FRAM.
Lead zirconate titanate (PZT) is recently considered as one of the most promising materials for DRO FRAM devices due to its excellent ferroelectric properties. There are remarkable advances in the applications of PZT thin films, but the direct integration into high density CMOS devices is restricted by high processing temperatures. Hence, it is desirable to lower processing temperature and develop novel high temperature electrode-barrier layers for achieving high density DRO FRAM devices.
The NDRO FRAM devices have been developed mainly using metal-ferroelectric-semiconductor (MFS) and metal-ferroelectric-metal-insulator-semiconductor (MFMIS) structure. This devices use the remanent polarization of ferroelectric films to control the surface conductivity of a silicon substrate. The problem of the NDRO FRAM is that the actual electric field applied to ferroelectric films is very small compared to the external electric field, because of the large depolarization field in the MFS structure and the high capacitance ratio of ferroelectric capacitor and SiO2 capacitor in series in the MFMIS structure. Since the typical ferroelectric films show very high dielectric constant over 400, it is desired to develop ferroelectric films with low dielectric constant and low coercive electric field.
This research is primarily focused on developing low temperature processing and high temperature electrode-barrier layers for DRO FRAM application, and exploiting novel ferroelectric materials for NDRO FRAM application. The low temperature processing was achieved by a novel sol-gel processing, which takes advantage of in-situ electrode template layer, rapid heating-treatment without pyrolysis step, and molecularly modified precursors. The PZT films with various composition were also investigated as a function of Ti content. In order to study the integration issues for these PZT films, a substrate was constructed as Pt/TiN/TiSi2/poly-Si, which represents a scheme of capacitor in high density DRO FRAM devices. The ferroelectric films were incorporated into the substrate, and their ferroelectric properties were investigated as a function of annealing temperature. Excellent ferroelectric properties were observed for the thin films processed at a low temperature of 500 °C as contacting between top Pt and bottom polysilicon.
The other approach we have taken to overcome the integration problems in high density DRO FRAM devices is to develop high temperature electrode barrier layers. In this research, Pt/IrO2/Ir hybrid layers were prepared on poly-Si substrate as high temperature electrode-barriers. The PZT films fabricated on the Pt/IrO2/Ir/poly-Si substrates exhibited good ferroelectric properties and outstanding fatigue properties after high temperature processing. It was observed from Auger electron spectroscopy (AES) profiles that the hybrid oxide electrode minimized fatigue problem by reducing the oxygen vacancies entrapment at the electrode/ferroelectric interfaces. This results indicated that Pt/IrO2/Ir high temperature electrode-barrier layers promise to solve major problems of PZT integration into high density DRO memory devices.
For the NDRO FRAM devices, Sr2Nb2O7 and La2Ti2O7 thin films were prepared on Pt-coated silicon, Si(100), and Pt/IrO2/SiO2/Si substrates by metalorganic deposition (MOD) technique. The Sr2Nb2O7 and La2Ti2O7 thin films showed the dielectric constant values of 48 and 46, respectively. However, no ferroelectricity was observed at room temperature, which might be attributed to extremely small grains. Extensive studies on preparation and properties of Sr2(Ta1-xNbx)O7 (STN) both in bulk and thin film form were carried out as a function of composition. The STN films exhibited small dielectric constant of around 46, irrespective of the composition.Ph. D.
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Shu, Chang. « Investigation of the structural and functional properties of lead-free barium calcium zirconate titanate piezoceramics ». Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8148/.
Texte intégralRésumé :
There is an urgent desire to move from lead-based piezoelectric materials to lead-free alternatives. One of the most promising lead-free materials has been reported to be zBao.7oCao.3oTi0J-(1-z) BaZro.2oTio.soOJ (abbreviated as zBCT-(1-z)BZT) system, which has comparable piezoelectric performance to lead-based materials. However, there is a lack of systematic research to investigate the effects of fabrication on the structural and functional properties of this zBCT -(1-z)BZT system. In this work, the end member Bai-xCaxTiOJ (x=0-0.30) and BaZryTii-y03 (ji=0-0.30) systems have been investigated. The phase transition diagrams of the two systems have been successfully established by measuring temperature dependent Raman spectroscopy and functional properties. The optimized fabrication procedure for forming single phased Bao.7oCao.3oTi0J and BaZro.2oTio.soOJ ceramics by solidstate methods, has been applied as a novel way to form zBCT-(1-z)BZT (O:Sz:~:J) ceramics by sintering the pre-calcined Bao.7oCao.3oTi0J and BaZro.2oTio.soOJ powders. A new phase diagram of the zBCT-(1-z)BZT (0$z:S1) has been constructed by combing structural and functional property measurements. It indicates a vertical orthorhombic phase region separating rhombohedral and tetragonal phases below the Curie temperature. The highest piezoelectric properties have been observed for z=0.5 ceramics at room temperature, due to the increased potential polarization directions in the vicinity of the orthorhombic to tetragonal phase boundary.
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Tong, Sheng. « Dielectric and Ferroelectric Properties of Lead Lanthanum Zirconate Titanate Thin Films for Capacitive Energy Storage ». University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1352993943.
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Gu, Xing. « High quality molecular beam epitaxy growth and characterization of lead titanate zirconate based complex-oxides ». VCU Scholars Compass, 2007. http://scholarscompass.vcu.edu/etd/1603.
Texte intégralRésumé :
Research interest in complex oxides has resurged owing to progress in modern epitaxial techniques. Among such oxides, lead-titanate-based thin films such as PbTiO3 (PTO) and Pb(ZrxTi1−x)O3 (PZT) offer attractive advantages for a wide variety of applications. Moreover, integration between functional oxides with compound semiconductors has the potential to realize multi-functional devices which enjoy the properties from both groups of materials. Ferroelectric materials with a perovskite structure (ABO3) and semiconductors such as GaN with a hexagonal structure, require a careful choice of a bridge layer and suitable epitaxial technique. Molecular beam epitaxy (MBE) has been an established technique in providing epitaxial growth with high crystal perfection and precise control over material composition. Single-crystal oxides grown by molecular beam epitaxy (MBE) can in principle avoid grain boundaries and provide a sharp interface as well.
In this dissertation, the MBE growth mechanism of PZT was investigated. In-situ RHEED patterns indicate that the growth of PTO and PZT occur in a two-dimensional, layer by layer mode, as confirmed by a streaky pattern. The crystal quality of PTO, PZO, and PZT thin films prepared by MBE are evaluated by X-ray diffraction (XRD), and have a full width at half maximum (FWHM) value of 4 arcmin for an 80nm thick layer. Optical properties of the PTO thin films have been characterized by variable angle spectroscopic ellipsometry (VASE), and well resolved dielectric functions are extracted. The refractive index is determined as 2.605 at 633 nm, and bandgap energy as 3.778eV. The electrical properties of the PTO and PZT are evaluated by the measurement of polarization-field hysteresis loops, give a remanent polarization of 83 μC/cm2 and a coercive field of 77 kV/cm. Lead oxide (PbO), titanium dioxide (TiO2), and zirconium dioxide (ZrO2), on GaN templates for potential PZT/GaN integration. The epitaxial growth of TiO2, PbO, and ZrO2 is realized on GaN templates for the first time by MBE. The PbO epitaxial layer was also used as a nucleation layer to enable single crystalline, perovskite PTO growth on GaN.
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Hewlett, Robert. « Solution-processed lead zirconate titanate as an interfacial modifier in hybrid oxide/polymer solar cells ». Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/24864.
Texte intégralRésumé :
Due to its excellent optoelectronic properties and ease of processing. ZnO has been considered a promising acceptor material in oxide:polymer hybrid photovoltaics (hPVs); however, devices have consistently underperformed for a number of reasons including poor charge generation and high recombination rates. The characteristics of the oxide:polymer interface have been cited as crucial in determining device performance: to this end, modification of the interface with both molecular and inorganic species has been shown to yield significant improvement. In this study, growth of the perovskite ferroelectric material lead zirconate titanate (PZT) is carried out on ZnO using sol-gel deposition. Subsequently, the PZT layers are used to modify the donor-acceptor interface in ZnO:poly(3-hexylthiophene) (P3HT) hPV devices: this study is carried out in order to lay the foundations for future investigations into the effect of ferroelectric properties on organic-based photovoltaics using inorganic ferroelectric materials. PZT was confirmed to crystallise on ZnO in the tetragonal phase and microstructural characterisation by atomic force microscopy revealed that the ZnO-PZT films consist of small, tightly packed PZT grains, indicating that the ZnO substrates provide a high seeding density for PZT. The ZnO-PZT interface was studied to determine the way by which growth proceeds in these films: whilst it was found that intermixing between the constituent elements of the two materials does not occur, transmission electron microscopy of the interface revealed the presence of a secondary phase thought to be orthorhombic PbO - it is hypothesised that this phase plays a role in the crystallisation of PZT. Growth and characterisation of low thickness PZT (< 15 nm) was conducted, confirming the crystallisation of tetragonal PZT for a film thickness of ~ 11 nm. Finally, the modification of bilayer ZnO:P3HT hPV devices with PZT was shown to have a positive effect on device performance: using transient absorption spectroscopy, the presence of the PZT layer was seen to increase the hole polaron lifetime from 15 μs to 2 ms, indicating a suppression of charge recombination. The open-circuit voltage (Voc) of the hPV devices was observed to increase from 0.162 to 0.734 V; moreover, prolonged illumination of up to 30 minutes led to further increases in Voc, reaching a maximum of 0.947 V - this was attributed to the progressive filling of electron traps with photoexcited charges, leading to a reduction in trap-assisted charge recombination.
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Karastamatis, Thomas. « Measuring the R-curves of lead zirconate titanate (PZT) from a surface crack in flexure (SCF) ». Thesis, Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/16713.
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Schönau, Kristin A. [Verfasser]. « In situ Synchrotron Diffraction of Lead-Zirconate-Titanate at its Morphotropic Phase Boundary / Kristin A Schönau ». Aachen : Shaker, 2008. http://d-nb.info/1162789948/34.
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Wang, Tianhong. « Fracture mechanics studies of failures of lead zirconate titanate ceramics under mechanical and/or electrical loadings / ». View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?MECH%202003%20WANG.
Texte intégralRésumé :
Thesis (Ph. D.)--Hong Kong University of Science and Technology, 2003.Includes bibliographical references (leaves 132-137). Also available in electronic version. Access restricted to campus users.
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Garcia, Melendrez Jose Angel. « Ferroelectric and ferroelastic phenomena in PZT thin films ». Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.707904.
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Planer, Jakub. « Ab-initio výpočty elektronických a strukturních vlastností olovo-zirkonátu-titanátu (PZT) ». Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-319928.
Texte intégralRésumé :
This work is focused on Density Functional Theory (DFT) calculations of oxygen vacancy diffusion barriers in mixed perovskite lead zirconate titanate and its pure counterparts. We found out that barrier heights are different in lead titanate and lead zirconate caused by the different localization of the excess electrons due to the oxygen vacancy formation. Diffusion barriers were also determined for titanium-rich mixed phases and compared to experimental values. This work contributes to clarify unusually low experimentally measured diffusion coefficients in PZT. We found out that the induced vacancy states are forming localized bonds to the lead atoms which causes the oxygen vacancies to become immobile due to the increase of the activation energy of the diffusion process.
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Sekhar, Praveen Kumar. « Process development and characterization of sol-gel lead zirconate titanate films for fabrication of flexural plate wave devices ». [Tampa, Fla.] : University of South Florida, 2005. http://purl.fcla.edu/fcla/etd/SFE0001125.
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Chang, Jhing-Fang. « Preparation and characterization of doped lead zirconate titanate Pb(ZrxTi1-x)O₃ films ». Thesis, Virginia Tech, 1992. http://hdl.handle.net/10919/42466.
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Jones, Paul M. « Nanoparticle synthesis via thin film ferroelectric templates : surface interactions and effects ». Thesis, Cranfield University, 2008. http://dspace.lib.cranfield.ac.uk/handle/1826/3491.
Texte intégralRésumé :
An investigation into the processes taking place at the surface interface of ferroelectric Pb(Zr1-x,Tix)O3 immersed in metal salt solution under ultraviolet illumination is presented. The semiconducting and switchable dipolar nature of this material allows the spatial separation and control of photo-induced reduction and oxidation across its surface interface. These properties can be of application in novel techniques such as the controlled growth of metallic nanoparticles across specific polar domains. 70nm thick Pb(Zr0.3,Ti0.7)O3 samples, PZT(30/70), are manufactured using the sol gel methodology, two crystallographic orientations being produced. The orientation being controlled by the substrate used; Si was used for [111] orientation and MgO for [100]. The initial work with wideband ultraviolet light shows that the reduction and growth of silver on the PZT surface is greatly influenced by the structure of the film. The crystallographic orientation of the film affects metal deposition such that on [111] films the metal deposits only on positive domains, where as the [100] films experience deposition on both positive and negative domains. This is shown to be due to the difference in width of the space charge region, Δw = 4.4nm, between the [111] and [100] samples so that the negative domain on [100] samples have 10 19 times higher chance of electron tunnelling compared to the [111]. It is also shown that grain boundaries have the greatest effect on the growth of metal, with a metal cluster growth rate 51 times faster than elsewhere on the surface. This increased rate of growth is due to the effect a grain boundary has on the surrounding area, the energy band bending at the boundary attracting charge carriers from the grains around it. The interface types ranked from greatest to lowest influence are grain boundaries, positive domains, domain boundaries and finally interphase boundaries.ii It is shown that the stern layer, strongly adsorbed charged ions of opposite sign to the surface charge, at the PZT/solution interface act as an insulating layer to metal reduction. The accumulation of photoexcited charge carriers at points along grain boundaries causes the surface potential gradient to alter and allows metal reduction and thus clusters to nucleate. The energy required to cause this variation is investigated by use of narrow band, 5nm bandwidth, ultraviolet. For energy from 4.4eV to 5 eV, it is found there is an increase in the average silver cluster cross sectional area by a ratio of ca 1.6 to 1 for both the [111] and [100] orientations of PZT. Finally it is shown that the type of metal salt used in the photochemical process affects the type of reaction that takes place at the sample surface. For a cation to reduce on positive domains its reduction potential needs to be below the bottom edge of the conduction band of PZT. Chloride salts, that sit above the conduction band, cause decomposition of the negative domains. Use is made of these effects to find the position of the bottom of the conduction band for PZT. It is found that across similar [111] PZT samples FeCl2 can both reduce on positive domains and decompose negative domains, this puts the bottom of the conduction band for PZT(30/70) between 4.06 and 4.36 eV from vacuum. It is also discovered that the type of anion affects the decomposition of the negative domains. Nitrate salts with cations above the conduction band cause no decomposition whereas chlorides do. The decomposition is shown to be the loss of Pb from the negative surface.
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Yeh, Liu Yu-En, et 葉劉育恩. « Lead Zirconate Titanate Thick Films by CO2 Laser Annealing ». Thesis, 2004. http://ndltd.ncl.edu.tw/handle/72964795164397652609.
Texte intégralRésumé :
碩士國立臺灣科技大學
機械工程系
92
Abstract In this thesis, lead zirconate titanate (PZT) thick films were prepared by a modified Sol-Gel method successfully. The microstructure of the thick film was transformed from the amorphous phase to the perovskite structure by carbon dioxide laser annealing. A PZT thick film about 10 micrometer was performed by spin coating method from the PZT nano-powder and a small amount dispersing agents in the precursor solution. Microstructure and properties of PZT thin and thick films were analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), ferroelectric testing system and transmission electron microscopy (TEM). Based on our investigation, as inclination angle of laser beam was 20o, PZT film had the best absorptivity with carbon dioxide laser energy. When the film layer increase, grain sizes of PZT film increase gradually by laser annealing. In addition, grain density of PZT film increase to make annealing energy decrease in need. Consequently, when the amount of nano-powder increase, it can help film structure to promote laser absorptivity. PZT thick film possesses sparse structure distinctly, due to nano powder size inconsistently. However, laser energy passed through the thick film, and the lattice position moved. It resulted in raising whole structure density because crystal drive in thermal energy. Investigations of ferroelectric properties show the remnant polarization (Pr) is 8.43μ C/cm2 and the value of coercive electric field (Ec) is 8.52 kV/cm for two-layer thin film. Moreover, Pr is increased to 17.42 μC/cm2 effectively and Ec is 28.26 kV/cm for eight-layer PZT film. In thick film, due to laser energy cannot pass through the film structure completely. Therefore, for the thick film above 10 micrometer, Pr is 7.66 μC/cm2 and Ec is 21.54 kV/cm. The property is not as good as furnace annealing. Laser energy can pass through only 5~6 micrometer in thick film, so thickness of thick film is about 5 micrometer that it has full energy pass through whole structure by laser annealing and get excellent ferroelectric property (Pr is 36.10 μC/cm2 and Ec is 19.66 kV/cm). The thick film properties are not only better than thin film, but also decrease the laser power density from 150 W/cm2 to 100 W/cm2. Furthermore, the temperature and thermal budget during processing had been to reduce effectively.
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Lin, Yu-Cyun, et 林育群. « Evaluation of mechanical properties of bulky Lead zirconate titanate ». Thesis, 2015. http://ndltd.ncl.edu.tw/handle/85538900472283591947.
Texte intégralRésumé :
碩士國立中興大學
機械工程學系所
103
This thesis evaluated Young’s modulus of bulky lead zirconate titanate (PZT) by micro tensile test, nanoindentation test and analytical calculation. First, bulky PZT was formed in dog bone shape using micro-milling and was tested in micro tensile test. Second, bulky PZT was measured by nanoindetation test. Finally, bulky PZT was bonded on copper substrates and shaped in the form of fixed-fixed beam. Resonant frequencies of fixed-fixed beam were evaluated and used to calculate Young’s modulus in analytical model. Average Young’s modulus 90.5GPa 92.73GPa and 75.6GPa were investigated by micro tensile test, by nanoindetation test and by analytical calculation.
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Hong, Eunki. « Surface micromachined peristaltic pumps using lead zirconate titanate film ». 2004. http://etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-450/index.html.
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Ciou, Ci-Jin, et 邱祺瑾. « The ferroelectric-ferroelastic twinning in lead zirconate titanate ceramics ». Thesis, 2010. http://ndltd.ncl.edu.tw/handle/43914249358505394877.
Texte intégralRésumé :
碩士國立中山大學
材料與光電科學學系研究所
98
The composition dependent variation of ferroelectric domain structure in lead zirconate titanate (Pb(Zr0.52Ti0.48)O3) ceramics have been investigated within the morphotropic phase boundary (MPB). Tetragonal phase in sintered samples were identified via X-ray diffractometry (XRD). Representative microstructures of ferroelectric domains were examined using scanning electron microscopy (SEM). α-boundaries, δ- boundaries, and π-boundaries were analyzed from the contrast of extreme fringe patterns by transmission electron microscopy (TEM). Twin planes for 90o domains lie in {011) and for 180o domains lie in {100) and {220) were determined by selected area diffraction patterns (SADP). Traditional contrast analysis was adopted for determining displacement vectors (R). 90o domains with R = ε[011] and 180o domains with R = n[001]. Convergent beam electron diffraction (CBED) was performed to identify crystalline phases of different domain configurations. By examined the symmetry along the Z = [100], [110], and [111] zone axis, both δ-boundaries and π-boundaries are tetragonal phase.
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Sahu, Niranjan. « Study of Crystal Structure and Electrical Properties on Lead Titanate and Lead Zirconate Titanate Based Ceramic Oxides ». Thesis, 2011. http://ethesis.nitrkl.ac.in/4436/1/Ph.D__Thesis_of_Niranjan_Sahu_(Corrected)_Date_07-09-12.pdf.
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The lead based perovskite material (PT, PZT) has so many technological applications such as:multilayer capacitor, dielectric resonator, thin film resistor, piezoelectric transducers, elecrostrictive actuators, hydrogen sensor, electro optical modulator, laser host, switch magnetic bubble memory etc. The property of the lead based material can also be enhanced by substituting different transition
materials within the perovskite.Again there is a very less report on the detailed crystal structure study (Employing the Rietveld Method) of the modified lead based perovskite ceramics.There were no detailed study on crystal structure and physical properties of Pb1-xLaxTiO3 (PLT) at high
concentration of La content.The introduction of an optimized amount of lanthanum (La) not only increases the stability but also softens the ferroelectric properties of the material.Also there was not much report on the detailed crystal structure (Employing the Rietveld method) and physical properties of B site modification of PLT with general formula (Pb0.70La0.30)(Ti1-xAx)O3,(A = Mn and Al). The main objective to study this material was to explore the structural and electrical properties of both iso(Mn3+) and aliovant (Al3+) substitution on the B site of Pb0.7La0.3TiO3 cubic perovskite. Manganese (Mn3+) as an acceptor ion may replace Ti4+ site and the addition segregates at grain boundaries. Mn doping in lead titanate is also a good candidate for fabricating piezoelectric devices. Mn belongs to valence unstable ions; it can affect the stability of the material.Aluminium does not have a bonding d-orbit or d-electrons, and has a stable valence and solely displays a valence of 3+,different from the isovalent substitutions for Ti4+.So the aliovalent substitutions of Al3+ for Ti4+ in Pb0.7La0.3TiO3 would be interesting for studying the doping effect on the crystal structure, lattice dynamics and electrical properties.The oxygen ion vacancy concentration in rare earth (La3+) and manganese modified lead titanate could have an important contribution to the electrical response of these materials. There are lots of reports on the structural and electrical properties of modified lead zirconate titanate ceramics in the MPB region. But there is hardly found few reports on the detailed crystalvii structure (Employing the Rietveld method) of lead zirconate titanate in and around the MPB region which overcomes the existence of two phases.The doping substituent can either occupy A-site, Bsite or both as donor or acceptor based on chemical valance with respect to the original ions.The substitution of the transition elements of the B-site will modify the electrical properties of the ferroelectric materials.It is also well known that the fluctuation of the oxidation state of the transition metal ions (Fe3+, Mn3+) results in the formation of oxygen ion vacancies to reserve the local electrical neutrality and causes thermally activated conduction.