Synthesis, X-ray crystal structure and dielectric measurements of a tetragonal tungsten bronze: Pb0.75K1.80Li1.70Nb5O15

2003 ◽  
Vol 218 (1) ◽  
Author(s):  
M. Elaatmani ◽  
A. Zegzouti ◽  
F. Capitelli ◽  
A. G. G. Moliterni ◽  
A. Migliori ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Tungsten Bronze ◽  
Dielectric Measurements ◽  
Tetragonal Tungsten Bronze ◽  
X Ray

AbstractTypical crystals Pb

scholarly journals Characterization of K6Ta10.8O30 Microrods with Tetragonal Tungsten Bronze-Like Structure Obtained from Tailings from the Penouta Sn-Ta-Nb Deposit

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2289
Author(s):  
Belén Sotillo ◽  
Lorena Alcaraz ◽  
Félix A. López ◽  
Paloma Fernández
Keyword(s):  
Crystal Structure ◽  
Tungsten Bronze ◽  
X Ray Diffraction ◽  
Tetragonal Tungsten Bronze ◽  
X Ray ◽  
The North ◽  
Recovered Material ◽  
North Of Spain ◽  
Scanning Electron

In this work, a deep characterization of the properties of K6Ta10.8O30 microrods has been performed. The starting material used to grow the microrods has been recovered from mining tailings coming from the Penouta Sn-Ta-Nb deposit, located in the north of Spain. The recovered material has been submitted to a thermal treatment to grow the microrods. Then, they have been characterized by scanning electron microscopy, X-ray diffraction, micro-Raman and micro-photoluminescence. The results of our study confirm that the K6Ta10.8O30 microrods have a tetragonal tungsten bronze-like crystal structure, which can be useful for ion-batteries and photocatalysis.

Structure and electrical properties of tetragonal tungsten bronze Ba2CeFeNb4O15

RSC Advances ◽  
2015 ◽  
Vol 5 (94) ◽  
pp. 76957-76962 ◽  
Author(s):  
Hongqiang Ma ◽  
Kun Lin ◽  
Laijun Liu ◽  
Baoling Yang ◽  
Yangchun Rong ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electrical Property ◽  
Electrical Properties ◽  
Impedance Spectroscopy ◽  
Electron Diffraction ◽  
Tungsten Bronze ◽  
Ac Impedance Spectroscopy ◽  
Tetragonal Tungsten Bronze ◽  
X Ray ◽  
Selected Area Electron Diffraction

The crystal structure and electrical property of a tetragonal tungsten bronze ceramic, BaCeFeNb4O15, were investigated by synchrotron X-ray powder diffraction, selected area electron diffraction, and AC impedance spectroscopy.

1 MV super-high-resolution electron microscopy of Nb2O5-WO3complex compounds with TTB type subcells

1978 ◽  
Vol 36 (1) ◽  
pp. 298-299
Author(s):  
Shigeo Horiuchi
Keyword(s):  
Crystal Structure ◽  
High Resolution ◽  
Composition Range ◽  
Tungsten Bronze ◽  
High Resolution Electron Microscopy ◽  
X Ray Diffraction ◽  
Tetragonal Tungsten Bronze ◽  
X Ray ◽  
Voltage Electron ◽  
Resolution Electron

It is known that, over a composition range in a Nb2-O5-WO3 system, the crystal structure of compounds is composed of subcells with tetragonal tungsten bronze ( TIB ) type.) Different models have however been reported for some of them. The crystals are usually prepared in sealed tubes and sometimes show different colours due to a reduction in spite of a definite starting composition. Moreover, they frequently include small domains, which make the structure analysis by x-ray diffraction very difficult. In the present study we examine a series of these compounds, prepared under various conditions, by a super-high-resolution, high-voltage electron microscope ( Hitachi 1250 ),in which the lattice fringes of 2.0 Å in width can be resolved at an accelerating voltage of 1 MV under an axial illumination with equipping a specimen goniometer.2)Fig.l is a crystal structure image of 4Nb2O5.9WO3. According to electron diffractions the lattice parameters are a=12.3, b=36.6 and c=3.94 Å (orthorhombic).

X-ray powder diffraction and dielectric study of BaTi1−x(Zn1/3Nb2/3)xO3 (x=0.025 and 0.9)

2008 ◽  
Vol 23 (3) ◽  
pp. 241-245
Author(s):  
L. Khemakhem ◽  
A. Kabadou ◽  
A. Ben Salah ◽  
N. Abdelmoula
Keyword(s):  
Crystal Structure ◽  
Dielectric Properties ◽  
Rietveld Refinement ◽  
Powder Diffraction ◽  
Dielectric Study ◽  
Relaxor Behavior ◽  
Dielectric Measurements ◽  
Compound A ◽  
Space Group ◽  
X Ray

Polycrystalline BaTi1−x(Zn1/3Nb2/3)xO3 (x=0.025 and 0.9) compounds were synthesized successfully and studied by XRD and dielectric measurements. The effects of the Ti/(Zn,Nb) ratio on the structure and dielectric properties of the compounds were investigated. XRD results indicated that the crystal structure of the x=0.09 compound is cubic perovskite with space group Pm3m and a=4.0095(4) Å. For the x=0.09 compound, a splitting of the (200) peak was observed near 40.2°, indicating that the crystal structure changed from cubic to tetragonal, with space group P4mm, a=4.026(4) Å, and c=4.0091(4) Å. Rietveld refinement of the crystal structures led to final confidence factors Rp=0.0353 and Rp=0.0349 for x=0.025 and 0.9, respectively. Dielectric measurements showed a relaxor behavior present in BaTi0.1(Zn1/3Nb2/3)0.9.

Synthesis and single crystal X-ray structure of the tetragonal tungsten bronze Pb0.91K1.72Li1.46Nb5O15

2010 ◽  
Vol 45 (11) ◽  
pp. 1204-1208
Author(s):  
F. Capitelli ◽  
M. Rossi ◽  
M. Elaatmani ◽  
A. Zegzouti
Keyword(s):  
Single Crystal ◽  
Tungsten Bronze ◽  
Tetragonal Tungsten Bronze ◽  
X Ray

Influence of Ti additions on the Texture and Dielectric Properties of LSBN-BST Complex Ceramics

1998 ◽  
Vol 541 ◽  
Author(s):  
J. Portelles ◽  
H. Amorín ◽  
J. M. Siqueiros ◽  
F.F. Castilión ◽  
E. Martínez ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Oxygen Vacancies ◽  
Tungsten Bronze ◽  
Material Structure ◽  
X Ray Diffraction ◽  
Strontium Barium ◽  
Tetragonal Tungsten Bronze ◽  
X Ray ◽  
First Results

AbstractThe stoichiometric La-Ti doped strontium-barium niobate ceramic system was obtained for different concentrations of Titanium ions (Ti=1,3,5,10,30,50 %), where the Nb5− was substituted by Ti4+ according to the following expression Sr0.255 La0.03Bao0.7Nb2−yTiyO6−y/2 (LSBN-BST). The oxygen vacancies thus created which, together with the vacancies in the A sites of the tetragonal tungsten-bronze (TTB) material structure, have an important influence on their texture and dielectric properties, due to the crucial role of the occupancy of the crystallographic sites. X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy and thermoelectric analyses are reported. We report the first results for thin films of LSBNT- 7 % obtained by the PLD technique. The diffraction pattern reveals the presence of the LSBNT structure without annealing.

Incommensurate modulations of relaxor ferroelectric Ca0.24Ba0.76Nb2O6(CBN24) and Ca0.31Ba0.69Nb2O6(CBN31)

2014 ◽  
Vol 70 (4) ◽  
pp. 743-749 ◽  
Author(s):  
Heribert A. Graetsch ◽  
Chandra Shehkar Pandey ◽  
Jürgen Schreuer ◽  
Manfred Burianek ◽  
Manfred Mühlberg
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Ferroelectric Phase Transition ◽  
Ferroelectric Phase ◽  
Tungsten Bronze ◽  
Orthorhombic Phase ◽  
Relaxor Ferroelectric ◽  
Tetragonal Symmetry ◽  
Tetragonal Tungsten Bronze

CBN crystals show a one- and a two-dimensionally modulated modification. The former is isotypic with orthorhombic Ba4Na2Nb10O30and the latter with the tetragonal tungsten bronze type of crystal structure. The orthorhombic form irreversibly transforms to the tetragonal polymorph at the ferroelectric phase transition near 603 K. Orthorhombic and tetragonal CBN24 slightly differ in the distribution of the Ba and Ca atoms over the incompletely filled Me1 and Me2 sites. The tetragonal symmetry is further broken in orthorhombic CBN24 by different amplitudes of the positional modulations of O atoms which are symmetrically equivalent in the TTB structure. A similar orthorhombic phase of CBN31 could be obtained by quenching from 1473 K.

scholarly journals Atomic resolution imaging of cation ordering in niobium–tungsten complex oxides

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Sumio Iijima ◽  
Wenhui Yang ◽  
Syo Matsumura ◽  
Ichiro Ohnishi
Keyword(s):  
Crystal Structures ◽  
Tungsten Bronze ◽  
Lithium Ion ◽  
Atomic Resolution ◽  
Energy Storage Materials ◽  
Cation Ordering ◽  
Tetragonal Tungsten Bronze ◽  
X Ray ◽  
Scanning Transmission ◽  
Complex Metal Oxide

AbstractEnergy dispersive X-ray emission imaging at atomic resolution is a powerful tool to solve order–disorder problems in complex metal oxide crystals, supplementing conventional X-ray or neutron diffraction. Here, we use this method, based on scanning transmission electron microscopy, to investigate cation ordering in ternary metal oxides 4Nb2O5·9WO3 and 2Nb2O5·7WO3, which have recently attracted attention as energy storage materials in lithium-ion batteries. Their crystal structures are a tetragonal tungsten bronze-type and its hybrid with a ReO3-type ‘block structure’, respectively. Our study reveals the presence of chemical ordering of metal ions in these materials, which have previously been assumed to be solid-solutions. In particular, we show that the two types of cations, Nb and W, are well ordered in their lattices, and that the Nb ions tend to occupy one third of the pentagonal channel sites. These results demonstrate that atomic resolution X-ray emission imaging is an effective alternative approach for the study of locally ordered crystal structures.

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