The Origin of the Ferroelectricity in the Bismuth Titanate Bi4Ti3O12 with Perovskite-Like Layered Structure

2015 ◽  
Vol 226 ◽  
pp. 17-22 ◽  
Author(s):  
Joanna A. Bartkowska ◽  
Jolanta Dercz ◽  
Daniel Michalik
Keyword(s):  
Room Temperature ◽  
Bismuth Titanate ◽  
Diffraction Method ◽  
Ceramic Materials ◽  
Ferroelectric Material ◽  
X Ray Diffraction ◽  
Electronic Industry ◽  
X Ray ◽  
Formation Behavior ◽  
Thermogravimetric Studies

The goal of this study was to investigate the origin of ferroelectricity in Bi4Ti3O12. The bismuth titanate Bi4Ti3O12 (BTO), which belongs to the Aurivillius family, is one of the most interesting compounds among the bismuth-based layered ceramics. BTO is a ferroelectric material with wide applications in the electronic industry, as capacitors, transducers, memory devices and sensors. Aurivillius structures are described with a general formula following form:Am-1Bi2BmO3m-1. BTO ceramic materials is an Aurivillius structure with m = 3. This ceramic materials were prepared by conventional mixed-oxide method of the solid state reaction. The temperature of the Bi4Ti3O12 sintering was selected on basis of thermogravimetric studies. The crystal structure of Bi4Ti3O12 was examined at room temperature with an X-ray diffraction method. Phase formation behavior was investigated using the differential thermal analysis (DTA) and the thermal gravimetric (TG). The microstructure was investigated by SEM method. Based on the Dorrian’s model, the value of displacements between bismuth ions and oxygen octahedra was calculated.

Fabrication of Bi6Fe2Ti3O18 Ceramics by Mixed Oxide Method

2012 ◽  
Vol 730-732 ◽  
pp. 100-104
Author(s):  
Agata Lisińska-Czekaj
Keyword(s):  
Room Temperature ◽  
Ceramic Powder ◽  
Diffraction Method ◽  
Elementary Cell ◽  
X Ray Diffraction ◽  
Stoichiometric Mixture ◽  
Pressing Method ◽  
X Ray ◽  
Cell Parameters ◽  
Ceramic Samples

In the present study Bi6Fe2Ti3O18 (BFTO) ceramics has been fabricated by solid state reaction from the mixture of simple oxides viz. Bi2O3, TiO2 and Fe2O3. Stoichiometric mixture of the powders was thermally analyzed so parameters of the thermal treatment were determined. The EDS measurements have shown conservation of the chemical composition of the ceramic powder after calcination. Hot-pressing method was used for final densification of ceramic samples. The crystalline structure of the sintered samples was examined by X-ray diffraction method at room temperature. It was found that BFTO ceramics sintered at T=980 °C adopted the orthorhombic structure of Aba2 (41) space group with the following elementary cell parameters: a=5.4567(2)Å, b=49.418(2) and c=5.4826(2). Details concerning the atom’s positions are presented.

On the tetragonality of the room-temperature ferroelectric phase of barium titanate, BaTiO3

2009 ◽  
Vol 42 (3) ◽  
pp. 480-484 ◽  
Author(s):  
Dean S. Keeble ◽  
Pamela A. Thomas
Keyword(s):  
Barium Titanate ◽  
Diffraction Pattern ◽  
Room Temperature ◽  
Ferroelectric Material ◽  
Tetragonal Symmetry ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Group Assignment ◽  
Growth Method

The room-temperature phase of the important ferroelectric material barium titanate, BaTiO3, was re-investigated by single-crystal X-ray diffraction on a sample grown by the top-seeded solution growth method, with the intention of demonstrating once again that the structure has tetragonal symmetry consistent with the space-group assignmentP4mmand thus resolving recent controversy in the scientific community and literature [Yoshimura, Kojima, Tokunaga, Tozaki & Koganezawa (2006).Phys. Lett. A,353, 250–254; Yoshimura, Morioka, Kojima, Tokunaga, Koganezawa & Tozaki (2007).Phys. Lett. A,367, 394–401]. To this end, the X-ray diffraction pattern of a small (341 µm3) sample of top-seeded solution-grown BaTiO3was measured using an Oxford Diffraction Gemini CCD diffractometer employing Mo Kα radiation and an extended 120 mm sample-to-detector distance. More than 104individual diffraction maxima observed out to a maximum resolution of 0.4 Å were indexed on two tetragonal lattices. These were identical to within the standard deviations on the lattice parameters and were related to each other by a single rotation of 119.7° about the [11\overline1] direction of the first tetragonal lattice (the major twin component), although the actual twinning operation that explains the observed diffraction pattern both qualitatively and quantitatively is shown to be conventional 90° twinning by them[101] operation. Importantly, it is not necessary to invoke either monoclinic symmetry or a coexistence of tetragonal and monoclinic phases to explain the observed diffraction data.

scholarly journals Structural and Optical Studies of Potential Ferroelectric Crystal: KDP Doped TGS

2013 ◽  
Vol 6 (1) ◽  
pp. 1-9 ◽  
Author(s):  
P. R. Deepti ◽  
J. Shanti
Keyword(s):  
Infrared Detectors ◽  
Room Temperature ◽  
Grown Crystal ◽  
High Sensitivity ◽  
Ferroelectric Material ◽  
X Ray Diffraction ◽  
Optical Studies ◽  
Ferroelectric Crystal ◽  
X Ray ◽  
Vis Spectroscopy

Triglycine sulphate (TGS), an important ferroelectric material has been widely used in the fabrication of high sensitivity infrared detectors at room temperature. Single crystals of KDP doped TGS was grown by slow evaporation method at room temperature in this study. The grown crystal was characterized by UV-Vis spectroscopy, FTIR spectroscopy, powder X-ray diffraction studies, and ferroelectric studies. KDP doped TGS crystals were found to be highly transparent and full faced. The experimental results evidence the suitability of the grown crystal for optoelectronic applications.  Keywords: Crystal growth; KDP-doped TGS; Ferroelectric studies  © 2014 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.  doi: http://dx.doi.org/10.3329/jsr.v6i1.16584 J. Sci. Res. 6 (1), 1-9 (2014)

Residual Stress Measurements of 4H-SiC Crystals Using X-Ray Diffraction

2014 ◽  
Vol 778-780 ◽  
pp. 453-456 ◽  
Author(s):  
Masashi Nakabayashi ◽  
Tatsuo Fujimoto ◽  
Hiroshi Tsuge ◽  
Kiyoshi Kojima ◽  
Kozo Abe ◽  
...  
Keyword(s):  
Residual Stress ◽  
Temperature Distribution ◽  
Room Temperature ◽  
Radial Direction ◽  
Large Strain ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plane Direction ◽  
Lateral Temperature

The room temperature residual stress of 4H-SiC wafers has been investigated using a precise X-ray diffraction method. A large strain was observed for the circumferential direction of wafers, more than ten times larger than those measured along the principal plane direction and the radial direction. Optimizing the lateral temperature distribution in growing crystals leads to reduction of residual stress of wafers with high crystal quality.

scholarly journals Rb-=SUB=-1-x-=/SUB=-Cs-=SUB=-x-=/SUB=-NO-=SUB=-3-=/SUB=- (x=0.025, 0.05, 0.1) монокристаллы и их исследование методом высокотемпературной рентгенографии

2018 ◽  
Vol 52 (6) ◽  
pp. 565
Author(s):  
А.Ф. Хазиева ◽  
В.И. Насиров ◽  
Ю.Г. Асадов ◽  
Ю.И. Алыев ◽  
С.Г. Джабаров ◽  
...  
Keyword(s):  
Melting Point ◽  
Room Temperature ◽  
Diffraction Method ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Transformation Temperatures ◽  
X Ray ◽  
Cell Parameters

AbstractPolymorphic transformations in Rb_0.975Cs_0.025NO_3, Rb_0.950Cs_0.05NO_3, and Rb_0.90Cs_0.1NO_3 crystals grown by us have been studied by the X-ray diffraction method. Four different modifications are found for crystals in the range from room temperature to the melting point. The transformation temperatures and the unit-cell parameters are determined for the crystals of these modifications.

Enhanced Dielectric Properties of Sintered MgFe1.98Nd0.02O4 Nanoparticles

2020 ◽  
Vol 42 (1) ◽  
pp. 87-87
Author(s):  
U Rafiq U Rafiq ◽  
M Hanif M Hanif ◽  
M Anis ur Rehman and A Ul Haq M Anis ur Rehman and A Ul Haq
Keyword(s):  
Dielectric Properties ◽  
Loss Factor ◽  
Room Temperature ◽  
Grain Shape ◽  
Sol Gel ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
Phase Purity ◽  
X Ray ◽  
Scanning Electron

Spinal MgFe1.98Nd0.02O4 was prepared by simplified sol-gel method. To measure the dielectric properties samples were sintered from 700-800 oC in the steps of 50 oC. The sample’s phase purity, crystallographic phase and crystallite size was measured by X-ray diffraction method (XRD). The pellets were analyzed in Scanning Electron Microscope for their surface morphology and grain shape. Dielectric properties were measured from 20 Hz to 3 MHz at room temperature. Samples sintered at 750 oC, showed highest value of AC conductivity which indicated that the material is suitable for use in sensors. However, minimum value of dielectric loss factor was obtained at 800 and#176;C which makes it more suitable for antenna applications.

Crystal and surface structures of Y2O3 nanoparticles at room temperature

2021 ◽  
pp. 2150371
Author(s):  
R. F. Rzayev
Keyword(s):  
Crystal Structure ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Room Temperature ◽  
Diffraction Method ◽  
Surface Structures ◽  
X Ray Diffraction ◽  
Cubic Symmetry ◽  
X Ray ◽  
Scanning Electron

In this work, the crystal and surface structures of Y2O3 nanoparticles were explored. The exploration of crystal structure was carried out by X-ray diffraction method at room temperature and under normal conditions. It was found that the crystal structure of the Y2O3 compound has a cubic symmetry with an Ia-3 space group. The lattice parameters have the values: [Formula: see text] Å. The surface structure was studied at room temperature and under normal conditions on Scanning Electron Microscope (SEM) microscope. It was found that the nanoparticles of the Y2O3 compound being in the range 20–40 nm are of [Formula: see text] nm size.

Structural Properties of 300 Å of Iron Films Grown on Polycrystalline Substrate

2019 ◽  
Vol 397 ◽  
pp. 69-75
Author(s):  
Radhia Boukhalfa ◽  
Hichem Farh
Keyword(s):  
Structural Properties ◽  
Room Temperature ◽  
Molecular Beam ◽  
Structural Characteristics ◽  
Diffraction Method ◽  
The Other ◽  
X Ray Diffraction ◽  
Iron Films ◽  
X Ray ◽  
Polycrystalline Substrate

In this manuscript, the structural properties such as the distance inter-reticular of samples is studied, In the fact, four samples were used symbolized as follows: E tAg(Å), the only difference is the thickness of the Silver buffer layer (tAg= 0, 50, 100 and 150 Å) to find out how the thickness of this layer depends on the structural characteristics of the Iron thin layer, all samples are deposited using molecular beam epitaxy (MBE) at room temperature onto Si (100) substrate. The structural properties of all samples examined using X-ray diffraction method at small and high angles. The small angles X-Ray diffraction curves confirmed to us that there is a clear difference between the surface structure of the samples by varying the number of Kiessig Fringes, Also high angles X-Ray diffraction curves assured us this difference through the clear variation in the angular positions of the peaks of Bragg and the distances inter-reticular values from a sample to the other.

Effects of Refraction and Reflection on Analysis of Thin Films by the Grazing-Incidence X-ray Diffraction Method

1989 ◽  
Vol 33 ◽  
pp. 109-120 ◽  
Author(s):  
Toru Takayama ◽  
Yoshiro Matsumoto
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Diffraction Method ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
Diffraction Intensity ◽  
X Ray ◽  
Evaporation Technique ◽  
Diffraction Peaks ◽  
Angular Shift

AbstractThe grazing-incidence X-ray diffraction (GIXD) method was employed to analyze two-layer thin films, which were the samples of Å lOO Å Au/500Å Cu/Si02(substrate) and 250Å Cu/500Å Au/SiO2(substrate), which were prepared by the evaporation technique under the condition that the SiO2substrate was at room temperature. Diffraction profiles were obtained at various glancing angles ( α ) and the data were analyzed as a function of α. The results were as follows : 1) Diffraction peaks were shifted to larger diffraction angles, because of the refraction of the incident X-ray beam. The angular shift has been approximated by the equation, α - α2- αc2)1/2, where αcis the total ref reflection critical angle of the material. 2) As a result of the correction of angular shift, the stress of the evaporated films was estimated to be null. 3) The broadening of the Cu diffraction peak and the enhancement of the Cu diffraction intensity occurred at angles near αcof Cu, due to the reflection of the X-ray beam at the Cu/Au interface.

scholarly journals Dielectric properties of bismuth titanate ceramics containing SiO2 and Nd2O3 as additives

2012 ◽  
Vol 6 (3) ◽  
pp. 117-122 ◽  
Author(s):  
Stanislav Slavov ◽  
Milena Krapchanska ◽  
Elena Kashchieva ◽  
Svetlin Parvanov ◽  
Yanko Dimitriev
Keyword(s):  
Room Temperature ◽  
Bismuth Titanate ◽  
Dielectric Materials ◽  
Dielectric Losses ◽  
X Ray Diffraction ◽  
Melt Quenching ◽  
X Ray ◽  
Quenching Method ◽  
Titanate Ceramics ◽  
Scanning Electron

Bismuth-titanate ceramics containing SiO2 and Nd2O3 as additives are synthesized by melt quenching method in the system Bi2O3-TiO2-Nd2O3-SiO2 in the temperature range of 1250-1500 ?C. The phase composition of the obtained materials is determined by X-ray diffraction analysis and energy dispersive spectroscopy. Using scanning electron microscopy different microstructures are observed in the samples depending on the composition. Different values of conductivity, dielectric losses and relative permittivity are obtained depending on the composition. It is established that all investigated samples are dielectric materials with conductivity between 10-9 and 10-13 (??cm)-1 at room temperature, dielectric permittivity from 1000 to 3000 and dielectric losses tg? between 0.0002 and 0.1.

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