Download or read book Synthesis Characterization and Optical Properties of Barium Titanate Films Sputtered Under Various Conditions written by John C. Olson and published by . This book was released on 1981 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt: Data is presented on BaTiO3 films which were rf sputtered on Pt, quartz and sapphire substrates at various temperatures and gas mixtures. Measurements of density, dielectric constant, electrical conductivity, X-ray diffraction, energy band gap from optical absorption and wavelength, and temperature dependence of refractive index are presented. Measurements were also made on a BaTiO3 single crystal and a hot-pressed ceramic pellet for direct comparison of bulk properties to those of the films. The results of this work demonstrate that a transition of the properties occurs between the amorphous and crystalline states depending on the surface temperature during sputtering. The transition is sluggish up to 700 C above which crystalline properties of the films appear rapidly. (Author).

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1991 with total page 1460 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.

Download or read book Synthesis and Characterization of Batio3 Pellets and Thin Films written by Meor Ahmad Faris Meor Ahmad Tajudin and published by . This book was released on 2014 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: Barium titanate was synthesized using a solid state approach and an aqueous method. Solid state syntheses were used to prepare barium titanate pellets using a powder metallurgy method. Appropriate amounts of barium carbonate and titanium dioxide powder were mixed together in an agate mortar. Barium titanate pellets were mixed according to 5 different ratios of Ba/Ti which are 1:0.9, 1:0.95, 1:1, 1:1.05, 1:1.1. Pellets were sintered in air at a temperature 1400 °C. Barium titanate thin films were prepared using an aqueous method. Sol-gel of barium titanate was prepared according to the similar ratios as pellets. Thin films of barium titanate sol-gel were deposited using a desktop printer onto a glass substrate and fired at 400 °C. Both pellets and thin films were characterized by X-ray diffraction, scanning electron microscope, Atomic Force Microscope (thin films only), and impedance spectroscopy. This thesis focuses on determination of dielectric properties of barium titanate including the resistance, capacitance, dielectric constant, relaxation frequency, and loss tangent. The highest density for the barium titanate pellets were 5.90 g/cm3 when a Ba:Ti ratio of 1:1 was used. The average thicknesses of the thin films were 2.89 nm as measured using the atomic force microscope and verified using the scanning electron microscope. Characteristic of barium titanate were observed under various temperatures starting from room temperature up to 450 °C (for pellets) and 300 °C (for thin films). The measured dielectric constant of the pellets at 10 kHz (at room temperature) varied from a maximum of 2810 to a minimum of 1375.

Download or read book Technical Abstract Bulletin written by and published by . This book was released on 1981 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proceedings of the Intersociety Energy Conversion Engineering Conference written by and published by . This book was released on 1997 with total page 798 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis Characterization and Applications of Barium Strontium Titanate Thin Film Structures written by Supriya Ashok Ketkar and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Barium Strontium Titanate (BST) based ferroelectric thin film devices have been popular over the last decade due to their versatile applications in tunable microwave devices such as delay lines, resonators, phase shifters, and varactors. BST thin films are promising candidates due to their high dielectric constant, tunability and low dielectric loss. Dielectric-tunable properties of BST films deposited by different deposition techniques have been reported which study the effects of factors, such as oxygen vacancies, film thickness, grain size, Ba/Sr ratio, etc. Researchers have also studied doping concentrations, high temperature annealing and multilayer structures to attain higher tunability and lower loss. The aim of this investigation was to study material properties of Barium Strontium Titanate from a comprehensive point of view to establish relations between various growth techniques and the film physical and electrical properties. The primary goal of this investigation was to synthesize and characterize RF magnetron sputtered Barium Strontium Titanate (Ba1-xSrxTiO3), thin film structures and compare their properties with BST thin films deposited by sol-gel method with the aim of determining relationships between the oxide deposition parameters, the film structure, and the electric field dependence. In order to achieve higher thickness and ease of fabrication, and faster turn around time, a [grave]stacked' deposition process was adopted, wherein a thin film (around 200nm) of BST was first deposited by RF magnetron sputtering process followed by a sol-gel deposition process to achieve higher thickness. The investigation intends to bridge the knowledge gap associated with the dependence of thickness variation with respect to the tunability of the films. The film structures obtained using the three different deposition methods were also compared with respect to their analytical and electrical properties.

Download or read book Synthesis and Properties of Barium Titanate Solid Solution Thin Films on Copper Substrates written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Barium titanate thin films were deposited via chemical solution deposition using a hybrid-chelate chemistry directly on copper foil substrates. A process was developed to crystallize and densify the ferroelectric films at 900C by using a reductive atmosphere containing nitrogen, hydrogen, water vapor, and oxygen impurities such that film constituents were oxidized to form barium titanate and the foil substrate remained metallic. The crystallized films are polycrystalline with equiaxed morphology and average grain diameters in excess of 100 nm. The dielectric properties exhibit permittivities in excess of 1800 at room temperature and zero bias with tunabilites of greater than 90% and high field loss tangents of less than 1%. A series of samples was prepared with varying grain and crystallite sizes by dividing and processing a single film over a range of temperature from 700 to 900C. This ensures that the chemical composition and film thickness is invariant for each sample. It is shown that the grain size increases with higher process temperatures and results in a concomitant increase in permittivity and tunability. These enhancements, combined with the constant paraelectricD erroelectric phase transition temperature, indicated that a combination of film crystallinity and grain size is responsible for diminished performance. The phase transition temperature and temperature coefficient of capacitance modified by partially substituting zirconium, hafnium, and tin for titanium. The resulting films were single phase and the phase transition shifts were consistent with bulk materials. A reduction in permittivity was observed for increasing substituent level and was attributed to a reduction in grain size for both barium titanate zirconate and barium titanate hafnate. Processing conditions were chosen to stabilize Sn2+ during the firing process in an attempt to flux the system and increase grain size. The barium titanate stannate films had less reduction in grain size.

Download or read book Transient Phase Transitions in Barium Titanate Thin Films Annealed in Millisecond Intervals written by Sudarshan Sundaravaratharajan and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Barium titanate, a commonly used bulk capacitor has found many interesting applications in the electronics industry. It is widely regarded for its use in capacitance storage devices, DRAM memory application and multi layered ceramic capacitors. Various studies have reported modifications of barium titanate for use in high-k applications and it warrants further interest in exploring various phase transitions of barium titanate thin films. In this study, amorphous to crystalline barium titanate phase transformations are discussed in light of optical properties. These phase transformations are induced during millisecond laser spike annealing of sputtered amorphous barium titanate thin films. Different sputter configurations are adopted in this study namely on-axis, and 90° off-axis. Dwell and peak temperature combinations of laser spike annealing were explored from 250 _s to 10 ms, and 600 °C to 1300 °C respectively. Optical data collection is enabled through high throughput reflectance spectroscopy and the reflectance profile is fitted with an optical model using Transfer Matrix Method (TMM). Based on the model fits, optical thickness decreased at higher dwells and at threshold temperature of 1050 °C for on-axis sputtered barium titanate, and refractive index variation is qualitatively understood across dwell - peak temperature phase map. The Transfer matrix model agrees well with the measured reflectance profiles. Further the TMM indicated that densification occurs at higher peak temperatures giving rise to refractive index and thickness variations across the annealed regions. Also, TMM model fits at onset of crystallization indicated that the amorphous barium titanate undergoes volume expansion prior to nucleation. Correlating with the previous laser spike annealing studies on off-axis barium titanate, it is understood that volume expansion occurs in both off-axis and on-axis sputtered barium titanate during millisecond laser spike annealing, however off-axis sample showed film delamination upon volume expansion whereas this volume expansion phase is stabilized in on-axis sputter configuration.

Download or read book Government Reports Announcements Index written by and published by . This book was released on 1989 with total page 1336 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electrochemical Synthesis and Characterization of Barium Titanate Films written by 伍祖璁 and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of Ferroelectric Domain Structure and Nonlinear Optical Properties in Barium Titanate Epitaxial Thin Films written by David J. Towner and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The ferroelectric material barium titanate exhibits exceptional electro-optic and dielectric properties, making it desirable for electro-optic applications, especially in thin film form. The effective nonlinear optical and dielectric properties of BaTiO3 films are determined by the ferroelectric domain structure. The ferroelectric domain structures of epitaxial BaTiO3 films on MgO (100) substrates were investigated using x-ray diffraction (XRD), scanning probe microscopy (SPM), and second harmonic generation (SHG) techniques.

Download or read book Ferroelectrics Literature Index written by T. F. Connolly and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 713 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research on ferroelectricity and ferroelectric materials started in 1920 with the discovery by Valasek that the variation of spontaneous polarization in Rochelle salt with sign and magnitude of an applied electric field traced a complete and reproducible hysteresis loop. Activity in the field was sporadic until 1935, when Busch and co-workers announced the observation of similar behavior in potassium dihydrogen phosphate and related compounds. Progress thereafter continued at a modest level with the undertaking of some theoretical as well as further experimental studies. In 1944, von Hippel and co-workers discovered ferroelectricity in barium titanate. The technological importance of ceramic barium titanate and other perovskites led to an upsurge of interest, with many new ferroelectrics being identified in the following decade. By 1967, about 2000 papers on various aspects of ferroelectricity had been published. The bulk of this widely dispersed literature was concerned with the experimental measurement of dielectric, crystallographic, thermal, electromechanical, elastic, optical, and magnetic properties. A critical and excellently organized cpmpilation based on these data appeared in 1969 with the publica tion of Landolt-Bornstein, Volume 111/3. This superb tabulation gave instant access to the results in the literature on nearly 450 pure substances and solid solutions of ferroelectric and antiferroelectric materials. Continuing interest in ferroelectrics, spurred by the growing importance of electrooptic crystals, resulted in the publication of almost as many additional papers by the end of 1969 as had been surveyed in Landolt-Bornstein.

Download or read book Synthesis Characterization and Application of Barium Titanate Particles in Light Emitting Devices written by Antoine Dumont and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The search for low-cost technologies that reduces our energy consumption is a priority in our struggle for the well-being of our environment. This project had two objectives : (1) Synthesizing BaTiO3 nanoparticles of a controlled size and structure for an electroluminescent device (ELD) (2) Analyzing the effect of doping barium titanate with lanthanum and optimizing the concentration for our application. The BaTiO3 particles created for this project will enable a more efficient use of the necessary electric energy for the emission of light in ELDs. They can also reduce the thickness of the overall device, which would result in lower production costs and increased brightness. The BaTiO3 was synthesized using a sol-gel method, which allows for the control of particle size and dopant concentration in 6 different powders. The material was characterized using scanning electron microscopy, X-ray diffraction analysis and X-Ray photoelectron spectroscopy (XPS). The XPS results showed a large split in the lanthanum's binding energy which was never discussed in the litterature. Following this, a hypothesis was advanced related to the interaction between the Ti-O strong bond and the lanthanum. The ELDs were screen-printed by hand using inks made from the experimental BaTiO3 and a ZnS commercial powder. The optimal concentration of dopant (0,5 mol% La) was obtained by using impedancte spectroscopy and photometry to determine, respectively, the electric permittivity of the BaTiO3 layer and the luminescence of the ELDs. One of the luminescent samples was found to be 600% brighter than the others. Although an anomaly among the samples, it is a real result and could reveal to be of great importance for the field of ELD research if it can be reproduced using a commercial printer.

Download or read book Structure of BaTiO3 written by Edward G. Grimsal and published by . This book was released on 1950 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government Reports Annual Index written by and published by . This book was released on 1982 with total page 1300 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sections 1-2. Keyword Index.--Section 3. Personal author index.--Section 4. Corporate author index.-- Section 5. Contract/grant number index, NTIS order/report number index 1-E.--Section 6. NTIS order/report number index F-Z.

Download or read book Investigation of Rare Earth doped Barium Titanate Thin Films and Their Optical Properties written by Andrew R. Teren and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Ridge waveguides were fabricated using the Er:BaTiO3 films doped with approximately 1 at.% Er. Pump/probe measurements showed stimulated emission resulted in a 2.4 dB reduction in the 1,540 nm absorption. It was concluded that to achieve net optical gain, the background losses need to be further reduced.

Download or read book Optical Properties of Rare Earth Doped Barium Titanate Thin Films Prepared by Metalorganic Vapor Deposition written by Bruce A. Block and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The microstructure of the $\rm BaTiO\sb3$ films was investigated. The surface roughness generally increased with thickness, and the films were composed of many small subgrains, 0.1 to 0.3 microns in diameter. Grain boundary grooving was responsible for the observed surface roughening. Deposition of the metalorganic precursor on the substrate prior to the initiation of growth also contributed greatly to the surface roughness.