Electrical and Raman Spectroscopic Studies on Aurivillius Layered-Pervoskite Ceramics

2019 ◽  
Vol 1154 ◽  
pp. 80-90
Author(s):  
Mohammed Abdul Basheer ◽  
Vagmare Gangadhar ◽  
Guduru Prasad ◽  
Gobburu Subramanya Kumar ◽  
Nandi Venkata Prasad
Keyword(s):  
Rare Earth ◽  
Complex Impedance ◽  
Spectroscopic Properties ◽  
Spectroscopic Studies ◽  
Rare Earth Ions ◽  
X Ray Diffraction ◽  
Raman Spectroscopic ◽  
Solid State Route ◽  
A Site ◽  
Rare Earth La

Double rare-earth (La; Sm/Gd) substituted Aurivillius family of Bismuth Layered Structured Ferroelectrics (BLSF) namely Bi2.6Sm0.2La0.2TiNbO9 (BSLT; sample-A), Bi2.6Gd0.2La0.2TiNbO9 (BGLT; sample-B), single phase ceramics were prepared by solid state route. In addition, intergrowth (x BSLT - (1-x) BGLT, where x=0.49; sample-C) and solid solution (BSLT­x - BGLTy; where x + y=0.4; sample-D) materials were prepared. Dielectric, ferroelectric and Raman spectroscopic properties were studied on the said above materials. The X-ray diffraction analysis and Raman spectra revealed well-formation of stable structure. Though, the sample-C and sample-D have lower coercive field, compared to the sample-A and sample-B, but they exhibited sharp hysterisis loop. Therefore the instrinsic defects of sample-D inhabits more sensitivity towards the ferroelectric behaviour. The results were corroborated to the impedance and dielectrical data. The results were consistent with the SEM micrographs and complex impedance plots. An attempt is made to understand the effect of rare-earth ions on A-site of layered-pervoskite structure, defined as: (Bi2O2)2+(An-1BnO3n+1)2-.The term n represents number of pervoskite blocks interleaved with the bismuth oxide layers.

Accidental formation of Gd4(SiO4)2OTe: crystal structure and spectroscopic properties

2015 ◽  
Vol 71 (7) ◽  
pp. 598-601 ◽  
Author(s):  
Marek Daszkiewicz ◽  
Lubomir D. Gulay
Keyword(s):  
Crystal Structure ◽  
Rare Earth ◽  
Room Temperature ◽  
Emission Spectra ◽  
Functional Materials ◽  
Spectroscopic Properties ◽  
Rare Earth Ions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Interest In Science

Designing new functional materials with increasingly complex compositions is of current interest in science and technology. Complex rare-earth-based chalcogenides have specific thermal, electrical, magnetic and optical properties. Tetragadolinium bis[tetraoxidosilicate(IV)] oxide telluride, Gd4(SiO4)2OTe, was obtained accidentally while studying the Gd2Te3–Cu2Te system. The crystal structure was determined by means of single-crystal X-ray diffraction. The compound crystallizes in the space groupPnma. Three symmetry-independent gadolinium sites were determined. The excitation and emission spectra were collected at room temperature and at 10 K. Gd4(SiO4)2OTe appears to be a promising optical material when doped with rare-earth ions.

scholarly journals SiO2-SnO2:Er3+ Glass-Ceramic Monoliths

2018 ◽  
Author(s):  
Lam Thi Ngoc Tran ◽  
Damiano Massella ◽  
Lidia Zur ◽  
Alessandro Chiasera ◽  
Stefano Varas ◽  
...  
Keyword(s):  
Rare Earth ◽  
Optical Sensors ◽  
Tin Dioxide ◽  
Sol Gel ◽  
Glass Ceramics ◽  
Building Blocks ◽  
Spectroscopic Properties ◽  
Silica Matrix ◽  
Rare Earth Ions ◽  
Planar Waveguides

The development of efficient luminescent systems, such as microcavities, solid state lasers, integrated optical amplifiers, optical sensors is the main topic in glass photonics. The building blocks of these systems are glass-ceramics activated by rare earth ions because they exhibit specific morphologic, structural and spectroscopic properties. Among various materials that could be used as nanocrystals to be imbedded in silica matrix, tin dioxide presents some interesting peculiarities, e.g. the presence of tin dioxide nanocrystals allows increase in both solubility and emission of rare earth ions. Here, we focus our attention on Er3+ - doped silica – tin dioxide photonic glass-ceramics fabricated by sol-gel route. Although the SiO2-SnO2:Er3+ could be fabricated in different geometrical systems: thin films, monoliths and planar waveguides we herein limit ourselves to the monoliths. The effective role of tin dioxide as luminescence sensitizer for Er3+ ions is confirmed by spectroscopic measurements and detailed fabrication protocols are discussed.

scholarly journals Noncovalent Bonds, Spectral and Thermal Properties of Substituted Thiazolo[2,3-b][1,3]thiazinium Triiodides

Crystals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 506 ◽  
Author(s):  
Irina Yushina ◽  
Natalya Tarasova ◽  
Dmitry Kim ◽  
Vladimir Sharutin ◽  
Ekaterina Bartashevich
Keyword(s):  
Electron Density ◽  
Noncovalent Interactions ◽  
Material Design ◽  
Spectroscopic Properties ◽  
Structural Features ◽  
Halogen Bonds ◽  
X Ray Diffraction ◽  
Raman Spectroscopic ◽  
Pairwise Interactions ◽  
Noncovalent Bonds

The interrelation between noncovalent bonds and physicochemical properties is in the spotlight due to the practical aspects in the field of crystalline material design. Such study requires a number of similar substances in order to reveal the effect of structural features on observed properties. For this reason, we analyzed a series of three substituted thiazolo[2,3-b][1,3]thiazinium triiodides synthesized by an iodocyclization reaction. They have been characterized with the use of X-ray diffraction, Raman spectroscopy, and thermal analysis. Various types of noncovalent interactions have been considered, and an S…I chalcogen bond type has been confirmed using the electronic criterion based on the calculated electron density and electrostatic potential. The involvement of triiodide anions in the I…I halogen and S…I chalcogen bonding is reflected in the Raman spectroscopic properties of the I–I bonds: identical bond lengths demonstrate different wave numbers of symmetric triiodide vibration and different values of electron density at bond critical points. Chalcogen and halogen bonds formed by the terminal iodine atom of triiodide anion and numerous cation…cation pairwise interactions can serve as one of the reasons for increased thermal stability and retention of iodine in the melt under heating.

Synthesis and Characterization of the Manganese Pyroarsenate Mn2As2O7 · 2H2O

2001 ◽  
Vol 56 (4-5) ◽  
pp. 359-363 ◽  
Author(s):  
N. Stock ◽  
G. D. Stucky ◽  
A. K. Cheetham
Keyword(s):  
Three Dimensional ◽  
Spectroscopic Studies ◽  
Mean Value ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Raman Spectroscopic ◽  
Distorted Octahedral ◽  
Ir And Raman ◽  
Hydrothermal Methods

Abstract The manganese pyroarsenate hydrate, Mn2As2O7 · 2 H2O, has been obtained as a single phase product using hydrothermal methods and the structure has been determined by single crystal X-ray diffraction. The title compound crystallizes in the monoclinic space group P21/n with a = 6.6576(4), b = 14.555(1), c = 7.8147(5) Å, β = 94.935(1)°, V = 754.46(8) Å3 and Z = 4. The manganese ions are each coordinated to five oxygen atoms and a water molecule in a distorted octahedral arrangement. Edge-sharing MnO6 octahedra form chains which are connected to a three-dimensional framework by As2O74- ions. The pyroarsenate anion, which attains a nearly eclipsed conformation, has a mean As-O distance for the terminal As-O bonds of 1.669(2) Å, while for the bridging oxygen atom a mean value of 1.757(2) Å is observed. Magnetic susceptibility measurements indicate the presence of high-spin Mn2+ ions. Thermogravimetric as well as IR and Raman spectroscopic studies of Mn2As2O7 · 2 H2O are presented.

The magnetic and spectroscopic properties of certain rare-earth double nitrates

1955 ◽  
Vol 232 (1191) ◽  
pp. 458-474 ◽  
Keyword(s):  
Rare Earth ◽  
Electric Field ◽  
Spectroscopic Properties ◽  
Rare Earth Ions ◽  
Rare Earth Ion ◽  
Crystalline Electric Field ◽  
Paramagnetic Resonance ◽  
Systematic Fashion ◽  
Resonance Data ◽  
Rare Earth Series

The theory that has been developed for rare-earth ions in crystals is here applied to the double nitrates. The paramagnetic resonance data and certain spectroscopic properties of the different rare-earth double nitrates, depending as they do on the crystalline electric field at a rare-earth ion, are related to the six parameters through which the field is defined. It is found that most of the experimental results can be fitted to values of the parameters that vary in a systematic fashion along the rare-earth series.

Synthesis, Morphology Control and Luminescent Properties of Rare Earth Ion-Doped CaWO4 Microstructures

2016 ◽  
Vol 16 (4) ◽  
pp. 4029-4034 ◽  
Author(s):  
Chunxia Liu ◽  
Lixia Yang ◽  
Dan Yue ◽  
Mengnan Wang ◽  
Lin Jin ◽  
...  
Keyword(s):  
Rare Earth ◽  
Uv Light ◽  
Luminescent Properties ◽  
Average Diameter ◽  
Rare Earth Ions ◽  
X Ray Diffraction ◽  
Hydrothermal Route ◽  
Rare Earth Ion ◽  
X Ray ◽  
Facile Hydrothermal Route

Rare earth ions (Tb3+, Eu3+) doped CaWO4 microstructures were synthesized by a facile hydrothermal route without using any templates and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) spectrum. The results indicate that the asprepared samples are well crystallized with scheelite structure of CaWO4, and the average diameter of the microstructures is 2∼4 μm. The morphology of CaWO4:Eu3+ microstructures can be controllably changed from microspheres to microflowers through altering the doping concentration of Eu3+ from 3% to 35%, and the microflowers are constructed by a number of CaWO4:Eu3+ nanoflakes. Under the excitation of UV light, the emission spectrum of CaWO4:Eu3+ is composed of the characteristics emission of Eu3+ 5D0-7FJ (J = 1, 2, 3, 4) transitions, and that of CaWO4:Tb3+ is composed of Tb3+ 5D4-7FJ (J = 6, 5, 4, 3) transitions. Both of the optimal doping concentrations of Tb3+ and Eu3+ in CaWO4 microstructures are about 5%.

scholarly journals X-ray diffraction and Raman spectroscopic studies of Zn-substituted carrboydite-like compounds

2006 ◽  
Vol 100 (1) ◽  
pp. 174-186 ◽  
Author(s):  
Yu-Hsiang Lin ◽  
Moses O. Adebajo ◽  
J. Theo Kloprogge ◽  
Wayde N. Martens ◽  
Ray L. Frost
Keyword(s):  
Spectroscopic Studies ◽  
X Ray Diffraction ◽  
X Ray ◽  
Raman Spectroscopic

Dependence of the Spectroscopic Properties of Europium on the Spatial Distribution of Rare-Earth Ions in Fluorophosphate Glasses

2005 ◽  
Vol 31 (4) ◽  
pp. 420-426 ◽  
Author(s):  
T. V. Bocharova ◽  
G. O. Karapetyan ◽  
A. M. Mironov ◽  
N. O. Tagil’tseva ◽  
O. V. Yanush
Keyword(s):  
Spatial Distribution ◽  
Rare Earth ◽  
Spectroscopic Properties ◽  
Rare Earth Ions

Optimization of Rare Earth Dope on MAl2O4 (M = Ba, Sr) by Self-Propagating High Temperature Synthesis

2012 ◽  
Vol 488-489 ◽  
pp. 442-446 ◽  
Author(s):  
Taschaporn Sathaporn ◽  
Sutham Niyomwas
Keyword(s):  
Rare Earth ◽  
High Temperature ◽  
Broad Band ◽  
Emission Spectra ◽  
Rare Earth Ions ◽  
Ocean Optics ◽  
X Ray Diffraction ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Microscope Technique

The Eu2+ doped barium aluminate (BaAl2O4:Eu2+) and strontium aluminate (SrAl2O4:Eu2+) with high brightness were synthesized by self-propagating high temperature synthesis (SHS) method. The influence of doping rare earth ions (Eu2+) on the luminescence of MAl2O4:Eu2+ were described in this study. The reactions were carried out in a SHS reactor under static argon gas at a pressure of 0.5 MPa. The morphologies and the phase structures of the products have been characterized by X-ray diffraction (XRD) and scanning electron microscope technique (SEM). The emission spectra of the products have been measured by an Ocean optics spectrometer at room temperature. Broad band UV excited luminescence was observed for BaAl2O4:Eu2+ and SrAl2O4:Eu2+ in the green region peak at λmax = 501 nm and 523 nm, respectively. The optimum Eu2+ doping ratio were 10.5 mol% and 6 mol% for BaAl2O4:Eu2+ and SrAl2O4:Eu2+, respectively

Synthesis and Characterization of Sr1−xBaxBi2Ta2O9 Materials

2000 ◽  
Vol 15 (8) ◽  
pp. 1661-1664 ◽  
Author(s):  
R. E. Melgarejo ◽  
M. S. Tomar ◽  
P. S. Dobal ◽  
R. S. Katiyar
Keyword(s):  
Spectroscopic Studies ◽  
Material System ◽  
X Ray Diffraction ◽  
Raman Spectroscopic ◽  
Complete Solid Solution ◽  
Solid Solution System ◽  
Ferroelectric Memory ◽  
Memory Applications ◽  
Barium Bismuth

Due to its endurance to ferroelectric fatigue, SrBi2Ta2O9 (SBT) has been extensively investigated. We report here the synthesis of Sr1−xBaxBi2Ta2O9 (x = 0.0, 0.1, 0.5, 1.0) using a solution-based route. The precursors used in this work were the salts of strontium, barium, bismuth, and tantalum ethoxide. X-ray diffraction and Raman spectroscopic studies indicated the formation of complete solid solution system for Sr1−xBaxBi2Ta2O9. This material system may provide interesting properties relevant to microwave tuning and ferroelectric memory applications, which are under investigation.

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