Tetragonal tungsten bronze phase potential in increasing the piezoelectricity of sol-gel synthesized (K0.5Na0.5)1-Li NbO3 ceramics

2021 ◽  
Author(s):  
Nor Huwaida Janil @ Jamil ◽  
Zalita Zainuddin ◽  
Mohammad Hafizuddin Hj Jumali ◽  
Izura Izzuddin ◽  
Lubna Nadzir
Keyword(s):  
Sol Gel ◽  
Tungsten Bronze ◽  
Tetragonal Tungsten Bronze

Epitaxial Growth of Sr0.3Ba0.7Nb2O6 Thin Films Prepared by Sol-Gel Process

1999 ◽  
Vol 606 ◽  
Author(s):  
Keishi Nishio ◽  
Jirawat Thongrueng ◽  
Yuichi Watanabe ◽  
Toshio Tsuchiya
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Epitaxial Growth ◽  
Raw Materials ◽  
Substrate Surface ◽  
Sol Gel ◽  
Tungsten Bronze ◽  
Monomethyl Ether ◽  
Tetragonal Tungsten Bronze ◽  
Sol Gel Process

AbstructWe succeeded in the preparation of strontium-barium niobate (Sr0.3Ba0.7Nb2O6 : SBN30)that have a tetragonal tungsten bronze type structure thin films on SrTiO3 (100), STO, or La doped SrTiO3 (100), LSTO, single crystal substrates by a spin coating process. LSTO substrate can be used for electrode. A homogeneous coating solution was prepared with Sr and Ba acetates and Nb(OEt)5 as raw materials, and acetic acid and diethylene glycol monomethyl ether as solvents. The coating thin films were sintered at temperature from 700 to 1000°C for 10 min in air. It was confirmed that the thin films on STO substrate sintered above 700°C were in the epitaxial growth because the 16 diffraction spots were observed on the pole figure using (121) reflection. The <130> and <310> direction of the thin film on STO were oriented with the c-axis in parallel to the substrate surface. However, the diffraction spots of thin film on LSTO substrate sintered at 700°C were corresponds to the expected pattern for (110).

Preparation and characterization of nanocrystalline potassium lithium niobate powders and films

2001 ◽  
Vol 16 (12) ◽  
pp. 3609-3613 ◽  
Author(s):  
H. X. Zhang ◽  
C. H. Kam ◽  
Y. Zhou ◽  
X. Q. Han ◽  
S. D. Cheng ◽  
...  
Keyword(s):  
Thin Films ◽  
Lithium Niobate ◽  
Near Infrared ◽  
Sol Gel ◽  
Tungsten Bronze ◽  
Ambient Atmosphere ◽  
Tetragonal Tungsten Bronze ◽  
Raman Scattering Spectroscopy ◽  
Infrared Wavelength ◽  
Optical Modes

Potassium lithium niobate (KLN) powders and thin films were prepared from metalorganic compounds through the sol-gel process. A homogeneous and stable KLN precursor was synthesized by mixing the metal ethoxides. Powder gels were obtained through the hydrolysis of the solution by exposing it to the ambient atmosphere. Thin films were deposited on Si, SiO2/Si, and fused quartz by a spin coating technique. The pyrolysis and crystallization of KLN powders and films were investigated through the methods of differential thermal analysis, thermogravimetric analysis, x-ray diffraction, and Raman scattering spectroscopy. The results revealed that both KLN powders and films could crystallize into a tetragonal tungsten–bronze-type phase with appropriate annealing. Optical studies indicated that the films were highly transparent in the visible–near-infrared wavelength range and could support optical modes.

Crystal Structure of Red Lead Titanate Thin Films

1997 ◽  
Vol 11 (26n27) ◽  
pp. 1181-1187
Author(s):  
L. A. Bursill ◽  
J. L. Peng ◽  
B. Jiang ◽  
X. Li
Keyword(s):  
Crystal Structure ◽  
Thin Films ◽  
Lead Titanate ◽  
Sol Gel ◽  
Tungsten Bronze ◽  
Tetragonal Tungsten Bronze ◽  
Transmission Electron ◽  
Red Lead ◽  
Hydrolysis Of ◽  
Perovskite Type

Orange-red lead titanate thin films are examined by high-resolution transmission electron microscopy and diffraction. It is remarkable that the structure is based on that of tetragonal-tungsten-bronze (TTB) rather than perovskite-type. The chemical basis for this result is examined, it is deduced that the TTB structure is stabilized by inclusion of hydroxyl ions during synthesis by a sol–gel route involving hydrolysis of n-Butyl titanate.

Processing Effects on the Microstructure of Sol-Gel Derived SBN Thin Films

1994 ◽  
Vol 346 ◽  
Author(s):  
L.A. Momoda ◽  
M.C. Gust ◽  
M.L. Mecartney
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Tungsten Bronze ◽  
Treatment Schedule ◽  
Size Distributions ◽  
Tungsten Bronze Structure ◽  
Tetragonal Tungsten Bronze ◽  
Transmission Electron ◽  
Processing Effects ◽  
Hydrolysis Conditions

ABSTRACTMicrostructural changes in sol-gel derived SrxBa1-xNb2O6 (SBN) thin films were monitored as a function of chemical variations in the precursor sol and of processing variations of the thin films. 6000À Sr0.5Ba0.5Nb2O6 thin films were deposited from different alkoxide based precursors under various hydrolysis conditions. The tetragonal tungsten bronze structure was achieved in films at temperatures on the order of 700°C. Preferential (001) orientation of the tetragonal lattice was found to be very dependent upon the substrate orientation as well as thermal treatment schedule. Transmission electron microscopy (TEM) was used to examine the film microstructure. Orientational effects were verified by TEM as well as a tendency for a porous structure in the alkoxide derived films. Substrate and processing dependent grain size and size distributions were also noted.

Tetragonal Tungsten Bronze Type Sn(II)-Based Quaternary Oxides: A New Type of Visible-Light-Absorbing Semiconductors for Photoelectrochemical Water Oxidation

2021 ◽  
Author(s):  
Yalong Zou ◽  
Jiabo Le ◽  
Yufeng Cao ◽  
Na An ◽  
Yang Zhou ◽  
...  
Keyword(s):  
Visible Light ◽  
Water Oxidation ◽  
Tungsten Bronze ◽  
Complex Oxides ◽  
Tetragonal Tungsten Bronze ◽  
Visible Light Absorption ◽  
New Type ◽  
Hydrogen Fuels ◽  
Photoelectrochemical Water Oxidation ◽  
Pec Water Splitting

The attractive photoelectrochemical (PEC) water splitting for hydrogen fuels always desires new semiconductors which provide stronger visible light absorption with suitable band positions. Sn(II) complex oxides are expected to offer...

Intergrowth of niobium tungsten oxides of the tetragonal tungsten bronze type

2020 ◽  
Vol 75 (11) ◽  
pp. 913-919
Author(s):  
Frank Krumeich
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Tungsten Bronze ◽  
Structural Complexity ◽  
Dark Field ◽  
Tetragonal Tungsten Bronze ◽  
Tungsten Oxides ◽  
Transmission Electron ◽  
Scanning Transmission

AbstractSince the 1970s, high-resolution transmission electron microscopy (HRTEM) is well established as the most appropriate method to explore the structural complexity of niobium tungsten oxides. Today, scanning transmission electron microscopy (STEM) represents an important alternative for performing the structural characterization of such oxides. STEM images recorded with a high-angle annular dark field (HAADF) detector provide not only information about the cation positions but also about the distribution of niobium and tungsten as the intensity is directly correlated to the local scattering potential. The applicability of this method is demonstrated here for the characterization of the real structure of Nb7W10O47.5. This sample contains well-ordered domains of Nb8W9O47 and Nb4W7O31 besides little ordered areas according to HRTEM results. Structural models for Nb4W7O31 and twinning occurring in this phase have been derived from the interpretation of HAADF-STEM images. A remarkable grain boundary between well-ordered domains of Nb4W7O31 and Nb8W9O47 has been found that contains one-dimensionally periodic features. Furthermore, short-range order observed in less ordered areas could be attributed to an intimate intergrowth of small sections of different tetragonal tungsten bronze (TTB) based structures.

Crystallization and dielectric properties of SrO–BaO–Nb2O5–GeO2 tungsten–bronze glass–ceramics

2001 ◽  
Vol 16 (7) ◽  
pp. 2057-2063 ◽  
Author(s):  
Jiin-Jyh Shyu ◽  
Hsin-Wei Peng
Keyword(s):  
Heat Treatment ◽  
Dielectric Properties ◽  
Tungsten Bronze ◽  
Glass Ceramics ◽  
Dielectric Behavior ◽  
Dendritic Morphology ◽  
Dielectric Constants ◽  
Two Stage ◽  
Tetragonal Tungsten Bronze ◽  
Stage Heat Treatment

The crystallization and dielectric properties of SrO–BaO–Nb2O5–GeO2 glass–ceramics were investigated. One- and two-stage heat-treatment methods were used to convert the parent glass to glass–ceramics. Strontium barium niobate (SBN) with a tetragonal tungsten-bronze structure formed as the major crystalline phase. When the crystallizing temperature/time was increased, the secondary crystalline BaGe2O5 phase coexisted with SBN. BaGe2O5 formed as a surface layer grown from the surface into the interior of the sample. The dendritic morphology of SBN crystals was examined. The glass–ceramics crystallized by two-stage heat treatment have higher dielectric constants than those crystallized by one-stage heat treatment. The highest dielectric constant that was obtained in the present glass–ceramics was 320. The glass–ceramics showed relaxor-type dielectric behavior.

Incommensurate modulation of calcium barium niobate (CBN28 and Ce:CBN28)

2012 ◽  
Vol 68 (2) ◽  
pp. 101-106 ◽  
Author(s):  
Heribert A. Graetsch ◽  
Chandra Shekhar Pandey ◽  
Jürgen Schreuer ◽  
Manfred Burianek ◽  
Manfred Mühlberg
Keyword(s):  
Crystal Structures ◽  
Tungsten Bronze ◽  
Atomic Displacement ◽  
Type Structure ◽  
Formula Unit ◽  
Tetragonal Tungsten Bronze ◽  
First Order ◽  
Oxygen Coordination ◽  
Incommensurate Modulation ◽  
Atomic Displacement Parameters

The incommensurately modulated crystal structures of Ca0.28Ba0.72Nb2O6 (CBN28) and Ce0.02Ca0.25Ba0.72Nb2O6 (Ce:CBN28) were refined in the supercentred setting X4bm(AA0,−AA0) of the 3 + 2-dimensional superspace group P4bm(aa½,−aa½). Both compounds are isostructural with a tetragonal tungsten bronze-type structure. The modulation of CBN28 consists of a wavy distribution of Ba and Ca atoms as well as vacancies on the incompletely occupied Me2 site with 15-fold oxygen coordination. The occupational modulation is coupled with a modulation of the atomic displacement parameters and a very weak modulation of the positional parameters of Me2. The surrounding O atoms show strong displacive modulations with amplitudes up to ca 0.2 Å owing to the cooperative tilting of the rigid NbO6 octahedra. The Me1 site with 12-fold coordination and Nb atoms are hardly affected by the modulations. Only first-order satellites were observed and the modulations are described by first-order harmonics. In Ce:CBN28 cerium appears to be located on both the Me2 and Me1 sites. Wavevectors and structural modulations are only weakly modified upon substitutional incorporation of 0.02 cerium per formula unit of calcium.

scholarly journals Effect of local A-site strain on dipole stability in A6GaNb9O30 (A = Ba, Sr, Ca) tetragonal tungsten bronze relaxor dielectrics

2015 ◽  
Vol 44 (23) ◽  
pp. 10738-10745 ◽  
Author(s):  
Andrew J. Miller ◽  
Andrei Rotaru ◽  
Donna C. Arnold ◽  
Finlay D. Morrison
Keyword(s):  
General Formula ◽  
Tungsten Bronze ◽  
Tetragonal Tungsten Bronze ◽  
A Site

A series of isovalently A-site substituted relaxor dielectric tetragonal tungsten bronzes of general formula Ba6−x−ySrxCayGaNb9O30 were investigated.

Structures and phase transitions in barium sodium niobate tungsten bronze (BNN)

2021 ◽  
Vol 77 (6) ◽  
Author(s):  
Thomas A. Whittle ◽  
Christopher J. Howard ◽  
Siegbert Schmid
Keyword(s):  
Phase Transitions ◽  
Room Temperature ◽  
Tungsten Bronze ◽  
Standard Setting ◽  
Experimental Results ◽  
Temperature Structure ◽  
Sodium Niobate ◽  
Tetragonal Tungsten Bronze ◽  
Space Group ◽  
The Subject

The room-temperature structure of the filled tetragonal tungsten bronze, Ba2NaNb5O15 (BNN), has been the subject of a number of studies, and these studies have given an almost corresponding number of different results. From a group theoretical examination of the different possibilities and a review of the published experimental results we conclude that the room-temperature structure is that proposed by Labbé et al. [J. Phys. Condens. Matter (1989), 2, 25–43] in the space group Bbm2 (Ama2 in standard setting) on a 2\sqrt{2}a × \sqrt{2}a × 2c cell. Upon heating, the structure remains ferroelectric but becomes tetragonal (space group P4bm) at 550 K, then paraelectric (space group P4/mbm) at and above 860 K.

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