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in subjects: "Ferroelectric Materials"

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Ferroelectric ceramics for dielectric power conversion. Annual report, March 1, 1979-April 30, 1980

Materials selected for study were those which could be expected to have useful Curie temperatures, resistivities, coercive fields, and Devonshire coefficients. Materials studied include PZT (lead-zirconia-titania system), Bi(Na,K)Ti/sub 2/O/sub 6/, rare earth titanoniobates, other tantalates and niobates, and thin films. Graphs are given for spontaneous polarization as a function of composition, temperature dependence of spontaneous polarization and coercive field for modified PSZT dielectrics,… more

Date: May 1, 1980

Creator: Payne, D. A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Physical motivations of the constitutive relations for ferroelectric ceramics and the existence of butterfly and hysteresis loops

The responses of ferroelectric ceramics can be quite complex depending on the physical processes to which they are subjected. Their mechanical, electromechanical and dielectric properties depend on domain switching, dipole dynamics and phase transformation which can be caused by external stimuli such as mechanical and electrical loadings, and temperature variations. A theory, taking into account the effects of domain switching and dipole dynamics, has been formulated, and in its present stage o… more

Date: January 1, 1982

Creator: Chen, P.J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Photoferroelectric effects in PLZT ceramics

A photoferroelectric effect described as photoassisted domain switching (PDS) is used to store high resolution, high contrast, nonvolatile optical information, including gray scale images in PLZT ceramics. Image storage is achieved by switching the ferroelectric remanent polarization while exposing the image on one of the indium tin oxide electroded surfaces of a PLZT plate, using near-UV light at the PLZT band gap energy (3.35 eV). PDS eliminates the photoconductive films required in previous … more

Date: January 1, 1977

Creator: Land, C.E. & Peercy, P.S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Remarkable Strontium B-Site Occupancy in FerroelectricPb(Zr1-xTix)O3 Solid Solutions Doped with Cryolite-Type StrontiumNiobate

New high-performance ferroelectric materials based on Pb(Zr{sub 1-x}Ti{sub x})O{sub 3} (PZT) that are doped with cryolite-type strontium niobate (SNO, Sr{sub 4}(Sr{sub 2-2y/3}Nb{sub 2+2y/3})O{sub 11+y}V{sub 0,1-y} with 0 {le} y {le} 1), hence denoted PZT:SNO, and their microscopic structure are described. The combination of exceptional piezoelectric properties, i.e. a piezoelectric strain constant of d{sub 33} {approx} 760 pm/V, with excellent stability and degradation resistance makes ferroele… more

Date: April 26, 2007

Creator: Feltz, A.; Schmidt-Winkel, P.; Schossman, M.; Booth, C.H. & Albering, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Phase transformation of poled "chem-prep" PZT 95/5-2Nb ceramic under quasi-static loading conditions.

Specimens of poled 'chem-prep' PNZT ceramic from batch HF803 were tested under hydrostatic, uniaxial, and constant stress difference loading conditions at three temperatures of -55, 25, and 75 C and pressures up to 500 MPa. The objective of this experimental study was to obtain the electro-mechanical properties of the ceramic and the criteria of FE (Ferroelectric) to AFE (Antiferroelectric) phase transformations so that grain-scale modeling efforts can develop and test models and codes using re… more

Date: October 1, 2004

Creator: Lee, Moo Yul; Montgomery, Stephen Tedford & Hofer, John H.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Response of ferroelectric ceramics to uniaxial stress. [Nb doped PZT 95/5]

Changes in electrical polarization of ferroelectric ceramics subjected to non-hydrostatic stress can be caused by rotation of ferroelectric domains, or, in the case of materials near ferroelectric to antiferroelectric phase boundaries, by a stress-induced phase transformation. Both processes have been observed in mechanical measurements on PZT 95/5. The results may have important implications for the operation of shock-actuated ferroelectric power supplies.

Date: January 1, 1979

Creator: Fritz, I.J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Chevron layer structures in surface stabilized ferroelectric liquid crystal (SSFLC) cells filled with a material which exhibits the chiral nematic to smetic C* phase transition

In this paper we report on the layer structure in Surface Stabilized Ferroelectric Liquid Crystal (SSFLC) electro-optic cells, adopted by a compound which exhibit the smectic C* (SC*) to chiral nematic (N*) phase transition. This class of compounds is unique in that the SC* layers form directly from the N* phase. These materials demonstrate a large tilt (/Theta/) of the director (/cflx n/) from the layer normal (/cflx z//prime/) immediately upon cooling into the SC* phase. Recent high resolutio… more

Date: January 1, 1989

Creator: Rieker, T.P.; Clark, N.A. & Safinya, C.R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Application of catastrophe theory to nuclear structure

Three two-parameter models, one describing an A-body system (the atomic nucleus) and two describing many-body systems (the van der Waals gas and the ferroelectric (perovskite) system) are compared within the framework of catastrophe theory. It is shown that each has a critical point (second-order phase transition) when the two counteracting forces controlling it are in balance; further, each undergoes a first-order phase transition when one of the forces vanishes (the deforming force for the nu… more

Date: January 1, 1979

Creator: Scharff-Goldhaber, G. & Dresden, M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Fluctuations in two-dimensional six-vertex systems

The character of polarization correlations in six-vertex systems is discussed. With the aid of a connection between the 1-d Heisenberg--Ising chain and the six-vertex problem, existing results for the chain correlations are used to obtain information about long-wavelength polarization correlations in six-vertex models. These results are compared with a neutron scattering study of 2-d polarization correlations in the layered compound copper formate tetrahydrate. Because the six-vertex model is e… more

Date: January 1, 1979

Creator: Youngblood, R.W.; Axe, J.D. & McCoy, B.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Report on Phase 1A of demonstration of scientific and economic feasibility of a solid-state heat engine

Progress is reported on the major tasks of this program including measurements of material parameters relevant to dielectric power conversion, hysteresis reversal time, Curie temperature, Devonshire coefficients, and resistivities. The engine cycle tests are reported, and performance versus predictions is analyzed. Engineering and economic projections are made based upon these results, and engineering and materials problems are identified. (WHK)

Date: January 31, 1979

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Demonstration of scientific and economic feasibility of a solid-state heat engine. Second annual report

A new experimental approach to the testing and data recording setup for ferroelectric converters is described. Thermocouple thermometry allowed low frequency thermal cycles to be measured. This lower frequency, in turn, allowed the employment of a Peltier effect module to pump heat into and out of the ferroelectric sample. The Peltier module is driven by a bipolar power supply whose output current (0 to +- 10 amp) is proportional to an input voltage. Thus, the amount of heat delivered to the sa… more

Date: November 16, 1979

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Properties and Characterization of Thin Film Ferroelectric Capacitors for Nonvolatile Memories

Thin film ferroelectric materials are the basis for a new, promising IC nonvolatile memory technology. The primary material being studied for ferroelectric memories is PZT. One of the key factors in determining the feasibility of PZT ferroelectric memories for weapon or space applications is whether PZT ferroelectric technology can be integrated into a radiation-hardened CMOS or bipolar process. Sandia National Laboratories has a program to study ferroelectric/CMOS process integration issues. T… more

Date: January 1, 1990

Creator: Nasby, R. D.; Schwank, J. R.; Rodgers, M. S.; Miller, S. L.; Tuttle, B. A.; Liang, A. Y. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Vacancy related defects in thin film Pb(ZrTi)O{sub 3} materials

Positron annihilation techniques have been applied to characterize vacancy-related defects in ferroelectric thin film structures. Variable energy positron beam measurements were carried out on doped and undoped Pb(ZrTi)O{sub 3} (PZT) samples subjected to different post-deposition cool down and anneal conditions. The PZT was deposited by sol-gel with either with platinum or RuO{sub 2} electrodes, or by laser ablation with La{sub 0.5}Sr{sub 0.5}CoO{sub 3} electrodes. The RuO{sub 2} and La{sub 0.5… more

Date: December 31, 1994

Creator: Krishnan, A.; Keeble, D. J.; Ramesh, R.; Warren, W. L.; Tuttle, B. A.; Pfeffer, R. L. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Effects of acetylacetone additions on PZT thin film processing

Sol-gel processing methods are frequently used for the fabrication of lead zirconate titanate (PZT) thin films for many electronic applications. Our standard approach for film fabrication utilizes lead acetate and acetic acid modified metal alkoxides of zirconium and titanium in the preparation of our precursor solutions. This report highlights some of our recent results on the effects of the addition of a second chelating ligand, acetylacetone, to this process. The authors discuss the changes … more

Date: February 1, 1995

Creator: Schwartz, R. W.; Assink, R. A.; Dimos, D.; Sinclair, M. B.; Boyle, T. J. & Buchheit, C. D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The MBE growth and optical quality of BaTiO{sub 3} and SrTiO{sub 3} thin films on MgO

High quality epitaxial BaTiO{sub 3} and SrTiO{sub 3} have been grown on MgO; stabilized at a one unit cell height; and grown to film thicknesses of 0.5--0.7 {mu}m. These relatively thick films remain adherent when thermally cycled between growth temperatures and room temperature, are crack free with high optical quality, and have both in-plane and out-of-plane X-ray rocking curves of 0.3--0.5{degree}. These films have been grown using molecular beam epitaxy (MBE) methods starting with the TiO{s… more

Date: May 1, 1994

Creator: McKee, R. A.; Specht, E. D.; Alexander, K. B. & Walker, F. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Defect structure of semiconducting and insulating epitaxial oxides. Progress report, May 1, 1993--April 30, 1994

The investigation has focused on epitaxial growth of BaSrTiO{sub 3} over the entire solid solution range, point defects in epitaxial BaTiO{sub 3} using temperature-dependent conductivity and deep-level optical spectroscopy, and their nonlinear optical properties.

Date: March 1, 1994

Creator: Wessels, B. W.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Solution chemistry optimization of sol-gel processed PZT thin films

We have optimized the ferroelectric properties and microstructural characteristics of sol-gel PZT thin films used in a CMOS-integrated, 256 bit ferroelectric non-volatile memory. The sol-gel process utilized in our work involved the reaction of Zr n-butoxide, Ti isopropoxide, and Pb (IV) acetate in a methanol/acetic acid solvent system. A 10-factor screening experiment identified solution concentration, acetic acid addition, and water volume as the solution chemistry factors having the most sig… more

Date: December 31, 1992

Creator: Lockwood, S. J. Schwartz, R. W.; Tuttle, B. A. & Thomas, E. V.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Mechanisms for the operation of thin film transistors on ferroelectrics

The electric field emanating from the surface of a poled ferroelectric can control the conduction properties of an overlaying semiconducting film, this combination of materials can thus serve as a non-destructive readout, non-volatile memory device. Here the authors will describe a variety of experimental studies of these devices designed to probe the physics of their operation. The experimental systems included sputtered, n-type semiconductor (SC) films of In{sub 2}O{sub 3} and ZnO deposited o… more

Date: December 31, 1993

Creator: Seager, C. H.; McIntyre, D.; Tuttle, B. A. & Evans, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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In situ, real-time analysis of the growth of ferroelectric and conductive oxide heterostructures by a new time-of-flight pulsed ion beam surface analysis technique

A new time-of-flight ion scattering and recoil spectroscopy ISARS) technique has been developed and is now used to perform in situ, real-time analysis of ferroelectric and conductive oxide layers during growth. Initial results presented here show various major effects, namely: (a) RuO{sub 2} films on MgO substrates appear to be terminated in O atoms on the top layer located in between Ru atoms lying in the layer underneath (This effect may have major implications for the explanation of the elim… more

Date: June 1, 1994

Creator: Auciello, O.; Krauss, A. R.; Gruen, D. M.; Lin, Y. & Chang, R. P. H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

High-pressure studies of soft mode transitions in solids

An overview of the soft mode concept and of high pressure studies of soft mode transitions in solids is given. Typical results on displacive ferroelectric (SbSI) antiferrodistortive (Gd/sub 2/(MoO/sub 4/)/sub 3/ and BaMnF/sub 4/) transitions as well as on coupled proton-phonon soft mode transitions (KH/sub 2/PO/sub 4/) are used to demonstrate that hydrostatic pressure can strongly modify the balance of forces responsible for soft mode behavior. Emphasis is placed on the physical implications of… more

Date: January 1, 1977

Creator: Samara, G. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Ultrafast Photovoltaic Response in Ferroelectric Nanolayers

We show that light drives large-amplitude structural changes in thin films of the prototypical ferroelectric PbTiO3 via direct coupling to its intrinsic photovoltaic response. Using time-resolved x-ray scattering to visualize atomic displacements on femtosecond timescales, photoinduced changes in the unit-cell tetragonality are observed. These are driven by the motion of photogenerated free charges within the ferroelectric and can be simply explained by a model including both shift and screenin… more

Date: February 15, 2012

Creator: Daranciang, Dan

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Time-of-flight pulsed ion beam surface analysis as a means of in situ, real-time characterization of the growth of ferro-electric and conductive oxide heterostructures

Pulsed beam Time-of-Flight Ion Scattering and Recoil Spectroscopy (TOF-ISARS) surface analysis methods have been developed which permit real-time, in situ characterization of the growth layer of multi-component oxide thin films. Results are presented from a study of the deposition of Pb, Zr, Ti and Ru using a sequential layer-by-layer deposition method under ambient oxygen pressure conditions appropriate to the growth of PZT films, revealing layer-by-layer as well as 2D and 3D island growth pro… more

Date: April 1, 1994

Creator: Krauss, A. R.; Gruen, D. M.; Auciello, O.; Lin, Y. & Chang, R. P. H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Photoferroelectric effects in BaTiO{sub 3} crystals

Intrinsic photo-induced changes in the hysteresis response in BaTiO{sub 3} single crystals have been observed by the application of ultra-violet (UV) light in combination with an applied bias. This UV/bias treatment suppresses the amount of switchable polarization by over 90%. The photoferroelectric effects observed are reproducible, reversible, and stable. Electron paramagnetic resonance measurements were also made to characterize the charge trapping associated with these hysteresis effects. T… more

Date: July 1, 1994

Creator: Warren, W. L.; Dimos, D. & Smyth, D. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Chem-prep PZT95/5 for neutron generator applications : the effect of pore former type and density on the depoling behavior of chemically prepared PZT 95/5 ceramics.

The hydrostatically induced ferroelectric(FE)-to-antiferroelectric(AFE) phase transformation for chemically prepared niobium modified PZT 95/5 ceramics was studied as a function of density and pore former type (Lucite or Avicel). Special attention was placed on the effect of different pore formers on the charge release behavior associated with the FE-to-AFE phase transformation. Within the same density range (7.26 g/cm3 to 7.44 g/cm3), results showed that ceramics prepared with Lucite pore form… more

Date: October 1, 2003

Creator: Lockwood, Steven John; Scofield, Timothy W.; Yang, Pin; Voigt, James A.; Tuttle, Bruce Andrew & Moore, Roger Howard

Item Type: Report

Partner: UNT Libraries Government Documents Department