Download or read book Processing and Structural Studies of Barium Strontium Titanate BaxSr1 xTiO3 Using the High Temperature Hydrothermal Technique written by Khairunisak Abdul Razak and published by . This book was released on 2007 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Processing Science of Barium Titanate 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 and barium strontium titanate thin films were deposited on base metal foils via chemical solution deposition and radio frequency magnetron sputtering. The films were processed at elevated temperatures for densification and crystallization. Two unifying research goals underpin all experiments: 1) To improve our fundamental understanding of complex oxide processing science, and 2) to translate those improvements into materials with superior structural and electrical properties. The relationships linking dielectric response, grain size, and thermal budget for sputtered barium strontium titanate were illustrated. (Ba0.6Sr0.4)TiO3 films were sputtered on nickel foils at temperatures ranging between 100-400 Ã'°C. After the top electrode deposition, the films were co-fired at 900 Ã'°C for densification and crystallization. The dielectric properties were observed to improve with increasing sputter temperature reaching a permittivity of 1800, a tunability of 10:1, and a loss tangent of less than 0.015 for the sample sputtered at 400 Ã'°C. The data can be understood using a brick wall model incorporating a high permittivity grain interior with low permittivity grain boundary. However, this high permittivity value was achieved at a grain size of 80 nm, which is typically associated with strong suppression of the dielectric response. These results clearly show that conventional models that parameterize permittivity with crystal diameter or film thickness alone are insufficiently sophisticated. Better models are needed that incorporate the influence of microstructure and crystal structure. This thesis next explores the ability to tune microstructure and properties of chemically solution deposited BaTiO3 thin films by modulation of heat treatment thermal profiles and firing atmosphere composition. Barium titanate films were deposited on copper foils using hybrid-chelate chemistries. An in-situ gas analysis process was developed to probe the organic removal and.
Download or read book Hydrothermal Processing of Barium Strontium Titanate Composites on Printed Circuit Board for Thin Film Varactor Applications written by and published by . This book was released on 2014 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thin film Ba0.7Sr0.3TiO3 has been deposited onto printed circuit boards at low temperatures for low and high frequency applications. The fabrication method involves spin coating sol-gel composites (a mixture of BST powder suspended in an amorphous BST sol), and treating the resultant films at 175°C. The treatment is done in an autoclave in an aqueous environment comprised of barium hydroxide, strontium hydroxide, and water, and is carried out at elevated temperature and pressure. This causes the amorphous BST sol to recrystallize, forming bridges that link the BST powders together, creating a dense network, leading to a higher dielectric constant. Three different types of powders have been explored for the composite. They are low-temperature derived, ceramic derived, and sol-gel derived powder. Low-temperature derived powders are the smallest in size, in the nanometer range. Due to such small sizes, the ferroelectric properties are lost, leading to no tunability and very low dielectric constant. The permittivity ranges from 30 to 55. Sol-gel derived powders are very reactive to the hydrothermal process. The resultant film permittivity is the highest, ranging from 200 to 260, but with a limited tunability of 1%. Ceramic derived powders are compatible with the process. The permittivity is less than that of sol-gel derived, with values from 130 to 140, but the tunability ranges from 4 to 8% at low frequencies (500 kHz to 20 MHz). For high frequency characterization (45 MHz to 1.15 GHz), films containing ceramic derived powder are deposited onto grounded coplanar waveguide capacitors. The dielectric constant significantly reduced, reaching as low as 18, but tunability increased to 18%.
Download or read book Bibliography written by Pierre Villars and published by Walter de Gruyter. This book was released on 2012-12-21 with total page 1827 pages. Available in PDF, EPUB and Kindle. Book excerpt: By browsing about 10 000 000 scientific articles of over 200 major journals mainly in a 'cover to cover approach' some 200 000 publications were selected. The extracted data is part of the following fundamental material research fields: crystal structures (S), phase diagrams (also called constitution) (C) and the comprehensive field of intrinsic physical properties (P). This work has been done systematically starting with the literature going back to 1900. The above mentioned research field codes (S, C, P) as well as the chemical systems investigated in each publication were included in the present work. The aim of the Inorganic Substances Bibliography is to provide researchers with a comprehensive compilation of all up to now published scientific publications on inorganic systems in only three handy volumes.
Download or read book Ceramic Abstracts written by and published by . This book was released on 2000 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hydrothermal Synthesis of Barium Strontium Titanate bst Powders and Continuous and Patterned Thin Films written by Xuezheng Wei and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Barium strontium titanate (BST) solid-solution oxides represent an important class of ferroelectric materials due to their high dielectric constants, composition dependent Curie temperature, and potential applications in dynamic random access memory (DRAM). Hydrothermal technique is a new low-temperature (
Download or read book Characterization of Barium Titanate and Strontium Titanate Nanoparticles Synthesized by Hydrothermal and Molten Salt Methods written by Jin Zhou and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis mainly focused on investigating the suitable synthesis methods to get barium titanate (BaTiO3) and strontium titanate (SrTiO3) nanocubes without using any capping agents. Two synthesis methods (hydrothermal and molten-salt) were used to synthesize BaTiO3 and SrTiO3 nanoparticles. X-ray diffraction (XRD) was used to identify phases and determine the phase purity of synthesized BaTiO3 and SrTiO3 nanoparticles. The morphology and formation mechanisms were investigated through scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was verified that BaTiO3 nanocubes can be successfully synthesized by molten-salt method, while SrTiO3 nanocubes were obtained by hydrothermal method. The synthesized nanocubes for both materials have high crystallinity and high purity. The formation mechanism of BaTiO3 nanocubes was proposed due to the low surface energy of {100} crystal planes. Crystal planes with low surface energy are preferred in the crystal growth stage. The formation of SrTiO3 nanocubes was proposed due to the crystal growth of {100} crystal planes and face-to-face attachment. These mechanisms provided clear explanations for the formation of BaTiO3 and SrTiO3 nanocubes without using any capping agents, which can be applied to other metal oxide nanocubes. Future studies can be focused on the synthesis of other metal oxide nanocubes by using the formation mechanisms proposed in this thesis.
Download or read book Electronic Structure of Barium Strontium Titanate by Soft x ray Absorption Spectroscopy written by and published by . This book was released on 1997 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt: Perovskite-type titanates, such as Strontium Titanate (STO), Barium Titanate (BTO), and Lead Titanate (PTO) have been widely studied because they show good electric and optical properties. In recent years, thin films of Barium Strontium Titanate (BST) have been paid much attention as dielectrics of dynamic random access memory (DRAM) capacitors. BST is a better insulator with a higher dielectric constant than STO and can be controlled in a paraelectric phase with an appropriate ratio of Ba/Sr composition, however, few studies have been done on the electronic structure of the material. Studies of the electronic structure of such materials can be beneficial, both for fundamental physics research and for improving technological applications. BTO is a famous ferroelectric material with a tetragonal structure, in which Ti and Ba atoms are slightly displaced from the lattice points. On the other hand, BST keeps a paraelectric phase, which means that the atoms are still at the cubic lattice points. It should be of great interest to see how this difference of the local structure around Ti atoms between BTO and BST effects the electronic structure of these two materials. In this report, the authors present the Ti L{sub 2,3} absorption spectra of STO, BTO, and BST measured with very high accuracy in energy of the absorption features.
Download or read book Mechanical and Microstructural Evaluation of Barium Strontium Titanate Thin Films for Improved Antenna Performance and Reliability written by and published by . This book was released on 1999 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ferroelectric barium strontium titanate (Ba(1-x)SrxTiO3 BSTO) films of 1-micron nominal thickness were deposited on single crystals of sapphire and electroded substrates at substrate temperatures varying from 30 deg C to 700 deg C. The microstructure of the thin films was columnar at all substrate deposition temperatures. The film microhardness showed a trend toward increased hardness with substrate temperature. Furthermore, with the elevation in substrate temperature, there was a parallel increase in film-substrate adhesion measurements, while the cohesion measurements were not influenced by substrate temperature.
Download or read book Barium Strontium Titanate written by Natheer Mahmood and published by LAP Lambert Academic Publishing. This book was released on 2014-03 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Barium Strontium Titanate Ba(x)Sr(1-x)TiO3 Is a solid solution between BaTiO3 and SrTiO3 which posses different Ferroelectric Curie temperature, Barium Strontium Titanate (BST) posses an adjustable value of Ferroelectric Curie temperature Tc depending on the value of (x). BST has wide range of applications depending on Curie temperature and Dielectric properties . BST used in communications especially in microwave tunable circuits, phase shifter, waveguides, antennas, MOSFET, MLCCs and Varactor.
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 Effect of Dispersant on Preparation of Barium Strontium Titanate Nanopowders by Microwave Hydrothermal Processing written by and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hydrothermal Synthesis of Sodium Bismuth Titanate and Titanate Nanofibers written by Animesh Kundu and published by ProQuest. This book was released on 2008 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: A hydrothermal processing method was developed for the synthesis of sodium bismuth titanate powders and thin films from suitable precursors at 150°C. Oxide precursors were best suited for preparing pure phase materials. The sodium bismuth titanate powders consisted of cube shaped crystals. A modified solution-reprecitation model involving partial dissolution of the precursors was proposed to explain the growth of these particles. The thin films were prepared on strontium titanate (100) substrate. A sample holder was specially designed and fabricated to secure the substrates in the reaction vessel. The result was a relatively smooth film of thickness & le;550 nm. The films were essentially single crystalline and had strong epitaxial relationship with the substrate. Titanate nanofibers (NaxH yTinO2n+1° zH2O) were known to form under similar hydrothermal conditions as sodium bismuth titanate powders. Detail research revealed that the pure hydroxide and oxide precursors tend to form sodium bismuth titanate powders or thin films. Titanate nanofibers were the predominant product when any other ions or organics were present in the precursor. Much faster reaction kinetics for the formation of nanofibers was observed when certain organic compounds were added deliberately with the precursors. Accordingly, a hydrothermal process was developed for converting the precursors to titanate nanofibers in a significantly shorter time than reported in the literature. A thin film consisting of vertically aligned nanofibers was prepared on titanium substrate at 150°C in as little as 30 minutes. Complete conversion of starting precursors to free standing nanofibers was achieved in & sim;8 hours at 150°C. The as-prepared nanofibers were some form of sodium titanate. They were converted to hydrogen titanate by ion exchange. Differential Scanning calorimetric experiments were performed to understand the thermal evolution of the fibers. The hydrogen titanate fibers underwent structural modifications even at temperatures less than 100°C. Research was done to understand the structure of these hydrogen titanate nanofibers with the aid of HRTEM, simulation of HRTEM images and x-ray diffraction. Initial results revealed that the fibers observed under the microscope had either a lepidocrocite type structure or an anatase type structure.
Download or read book Hydrothermal Conversion of Diatom Frustules Into Barium Titanate Based Replicas written by Eric Michael Ernst and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Numerous organisms produce ornately detailed inorganic structures (often known as shells) with features on length scales from the nanoscale to the microscale. One organism, commonly referred to as a diatom, originates from algae and is found throughout the oceans on Earth. These diatoms possess skeletal structures, frustules, made from silicon dioxide. This chemical makeup limits the number of possible applications for which these structures can be used. Using a series of gas displacement reactions, these frustules can be converted to other useful materials, such as magnesium oxide and titanium dioxide, while maintaining the features of the frustule template. In the current research, silicon dioxide frustules were converted to titanium dioxide replicas using method previously devised by our group. The titanium dioxide replicas were subjected to a hydrothermal reaction by exposing the replicas to an aqueous basic solution containing barium hydroxide to form barium titanate and barium strontium titanate replicas. The effects of reaction temperature, time, and solution composition on extent of conversion were examined. The conventional method of converting titanium dioxide to barium titanate, using a convection heating oven, was compared with a microwave assisted heating method to study the advantages of using microwave heating over convection heating.
Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2734 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Ceramic Materials for Electronics written by Relva C. Buchanan and published by CRC Press. This book was released on 2018-10-08 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Third Edition of Ceramic Materials for Electronics studies a wide range of ceramic materials, including insulators, conductors, piezoelectrics, and ferroelectrics, through detailed discussion of their properties, characterization, fabrication, and applications in electronics. The author summarizes the latest trends and advancements in the field, and explores important topics such as ceramic thin film, functional device technology, and thick film technology. Edited by a leading expert on the subject, this new edition includes more than 150 pages of new information; restructured reference materials, figures, and tables; as well as additional device application-oriented segments.
