scholarly journals The crystallization and optical properties of LiNbO3 single crystals

2000 ◽  
Vol 65 (5-6) ◽  
pp. 391-397 ◽  
Author(s):  
Aleksandar Golubovic ◽  
Rados Gajic ◽  
Slobodanka Nikolic ◽  
Stevan Djuric ◽  
Andreja Valcic
Keyword(s):  
Optical Properties ◽  
Single Crystals ◽  
Ferroelectric Properties ◽  
Wave Number ◽  
Published Data ◽  
Phonon Modes ◽  
Number Range ◽  
Air Atmosphere ◽  
Domain Structures ◽  
Crystal Diameter

LiNbO3 single crystals were grown by the Czochralski technique in an air atmosphere. The critical crystal diameter Dc = 1.5 cm and the critical rate of rotation wc = 35 rpm were calculated from the dynamic of fluids equations for buoyancy-driven and forced convections under which the shape of the melt/crystal interface changed. The domain inversion was carried out at 1473 K using a 10 min 3.75 V/cm electric field. The obtained crystals were cut, polished and etched to determine the presence of dislocations and single domain structures. The lattice parameters a = 0.51494 nm, c = 1.38620 nm and V = 0.3186 nm 3 were determined by X-ray powder diffraction. The optical properties were studied by infrared spectroscopy in the wave number range 20. 5000 cm -1. With decreasing temperature, an atypical behaviour of the phonon modes, due to the ferroelectric properties of LiNbO3 single crystal, could be seen. The optical constants were calculated by Kramers-Kronig analysis and the value of the critical temperature was estimated. The obtained results are discussed and compared with published data.

scholarly journals Phonon anomalies in optical spectra of LnNbO3 single crystals

2004 ◽  
Vol 69 (6) ◽  
pp. 493-502 ◽  
Author(s):  
Aleksandar Golubovic ◽  
Rados Gajic ◽  
Ivana Hinic ◽  
Andreja Valcic
Keyword(s):  
Single Crystals ◽  
Published Data ◽  
Czochralski Technique ◽  
Phonon Modes ◽  
Critical Rate ◽  
Air Atmosphere ◽  
Domain Structures ◽  
Infrared And Raman Spectroscopy ◽  
Crystal Diameter ◽  
Domain Inversion

LiNbO3 single crystals were grown by the Czochralski technique in an air atmosphere. The critical crystal diameter Dc = 1.5 cm and the critical rate of rotation ?c=35 rpm were calculated by equations from the hydrodynamics of the melt. The domain inversion was carried out at 1430 K using a 3.75 V/cm electric field for 10 min. The obtained crystals were cut, polished and etched to determine the presence of dislocations and single domain structures. The optical properties were studied by infrared and Raman spectroscopy as a function of temperature. With decreasing temperature, an atypical behaviour of the phonon modes could be seen in the ferroelectrics LiNbO3. The obtained results are discussed and compared with published data.

scholarly journals The optical properties of LiNbO3 single crystals obtained in air atmosphere

1999 ◽  
Vol 64 (10) ◽  
pp. 637-646 ◽  
Author(s):  
Aleksandar Golubovic ◽  
Slobodanka Nikolic ◽  
Rados Gajic ◽  
Stevan Djuric ◽  
Aleksandar Jelisijevic ◽  
...  
Keyword(s):  
Optical Properties ◽  
Single Crystals ◽  
Optical Constants ◽  
High Temperature Superconductor ◽  
Critical Diameter ◽  
Published Data ◽  
Critical Rate ◽  
X Ray ◽  
Air Atmosphere ◽  
Reflectance Data

Single crystals of LiNbO3 were grown by the Czochralski technique in an air atmosphere. The critical diameter and the critical rate of rotation were calculated. X-Ray measurements of the powder were carried out to obtain the lattice parameters.The optical constants were calculated by Kramers-Kronig analysis of reflectance data. The optical properties of LiNbO3 single crystals were studied for samples grown in an air atmosphere to investigate the influence of air on the optical properties of the formed crystals. A peak due to OH. gtroups appears in the transmission spectrum at 3385 cm -1. It was still present after annealing in an air atmosphere at temperature up to 873 K, but it was no longer detectable after annealing at 1473 K in an electric field. Thick films of the high-temperature superconductor YBa2Cu3O7 (Ag) were obtained on plates of LiNbO3 single crystals. The obtained results are discussed and compared with published data.

scholarly journals The optical properties of bismuth germanium oxide single crystals

2000 ◽  
Vol 65 (9) ◽  
pp. 611-618 ◽  
Author(s):  
Aleksandar Golubovic ◽  
Rados Gajic ◽  
Changkang Chen ◽  
Andreja Valcic
Keyword(s):  
Optical Properties ◽  
Single Crystals ◽  
Optical Constants ◽  
Published Data ◽  
Germanium Oxide ◽  
Reflection Spectra ◽  
Czochralski Technique ◽  
Phonon Modes ◽  
Bismuth Germanium Oxide ◽  
Wave Numbers

Bi12GeO20 single crystals were grown by the Czochralski technique. Suitable polishing and etching solutions were determined. Reflection spectra were recorded in the wave numbers range 20-5000 cm-1, and compared with the spectra of Bi12SiO20 single crystals to study the position of the phonon modes. The optical constants of the Bi12GeO20 single crystals were obtained using Kramers-Kronig analysis. The obtained results are dicussed and compared with published data.

FT-IR Spectroscopic and XRD Studies on Tris-Thiourea Strontium Chloride Single Crystals

2011 ◽  
Vol 8 (1) ◽  
pp. 201-204
Author(s):  
H. O. Jethva ◽  
R. R. Hajiyani
Keyword(s):  
Single Crystals ◽  
Xrd Analysis ◽  
Wave Number ◽  
Strontium Chloride ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Number Range ◽  
Aqueous Solvent ◽  
Powder Xrd Analysis ◽  
Ft Ir

There are various nonlinear optical materials having crystalline nature and find various applications in science and technology. Tris-thiourea strontium chloride was synthesized and single crystals were grown by the slow solvent evaporation technique using aqueous solvent. The grown crystals were characterized by Fourier Transform Infrared Spectroscopy (FT-IR), and X-ray diffraction analysis (XRD). The FT-IR spectra of these crystals were recorded in the wave number range 400-4000 cm-1 which reveals the presence of various functional groups. The powder XRD analysis suggested orthorhombic crystal structure.

scholarly journals The growth of Mg2TiO4 single crystals using a four-mirror furnace

2011 ◽  
Vol 76 (11) ◽  
pp. 1561-1566 ◽  
Author(s):  
Aleksandar Golubovic ◽  
Marko Radovic
Keyword(s):  
Optical Properties ◽  
Single Crystal ◽  
Diffraction Analysis ◽  
Single Crystals ◽  
Powder Diffraction ◽  
Spectroscopic Ellipsometry ◽  
Lattice Parameter ◽  
Published Data ◽  
X Ray ◽  
Float Zone

A single crystal of Mg2TiO4 was grown by the travelling solvent float zone (TSFZ) method. The lattice parameter a = 0.8444(8) nm was determined by X-ray powder diffraction analysis. The optical properties of the Mg2TiO4 single crystals were studied using spectroscopic ellipsometry. The obtained results are discussed and compared with published data.

scholarly journals The growth of sapphire single crystals

2001 ◽  
Vol 66 (6) ◽  
pp. 411-418 ◽  
Author(s):  
Aleksandar Golubovic ◽  
Slobodanka Nikolic ◽  
Stevan Djuric ◽  
Andreja Valcic
Keyword(s):  
Crystal Growth ◽  
Single Crystals ◽  
Powder Diffraction ◽  
Chemical Polishing ◽  
Published Data ◽  
Czochralski Technique ◽  
Critical Rate ◽  
Etching Solution ◽  
X Ray ◽  
Crystal Diameter

Sapphire (Al2O3) single crystals were grown by the Czochralski technique both in air and argon atmospheres. The conditions for growing sapphire single crystals were calculated by using a combination of Reynolds and Grash of numbers. Acritical crystal diameter dc = 20 mm and the critical rate of rotation c = 20 rpm were calculated from the hydrodynamics of the melt. The value of the rate of crystal growth was experimentally found to be 3.5 mm/h. According to our previous experiments, it was confirmed that three hours exposures to conc. H3PO4 at 593 K was suitable for chemical polishing. Also, three hours exposure to conc.H3PO4 at 523Kwas found to be a suitable etching solution. The lattice parameters a = 0.47573 nm and c = 1.29893 nm were determined by X-ray powder diffraction. The obtained results are discussed and compared with published data.

scholarly journals The growth of Nd: YAG single crystals

2002 ◽  
Vol 67 (4) ◽  
pp. 291-300 ◽  
Author(s):  
Aleksandar Golubovic ◽  
Slobodanka Nikolic ◽  
Rados Gajic ◽  
Stevan Djuric ◽  
Andreja Valcic
Keyword(s):  
Crystal Growth ◽  
Single Crystals ◽  
Powder Diffraction ◽  
Lattice Parameter ◽  
Argon Atmosphere ◽  
Published Data ◽  
Czochralski Technique ◽  
Critical Rate ◽  
X Ray ◽  
Crystal Diameter

Y3Al5O12 doped with 0.8%wt.Nd (Nd:YAG) single crystals were grown by the Czochralski technique under an argon atmosphere. The conditions for growing the Nd:YAG single crystals were calculated by using a combination of Reynolds and Grashof numbers. The critical crystal diameter and the critical rate of rotation were calculated from the hydrodynamics of the melt. The crystal diameter Dc=1.5 cm remained constant during the crystal growth while the critical rate of rotation changed from ?c=38 rpm after necking to ?c=13 rpm at the end of the crystal. The value of the rate of crystal growth was experimentally found to be 0.8?1.0 mm/h. According to our previous experiments, it was confirmed that 20 min exposure to conc. H3PO4 at 603 K was suitable for chemical polishing. Also, one-hour exposure to conc. H3PO4 at 493 K was found to be suitable for etching. The lattice parameter a=1.201 (1) nm was determined by X-ray powder diffraction. The obtained results are discussed and compared with published data.

scholarly journals Single crystals of bismuth silicon oxide grown by the czochralski technique and their characterisation

1999 ◽  
Vol 64 (9) ◽  
pp. 553-561 ◽  
Author(s):  
Aleksandar Golubovic ◽  
Slobodanka Nikolic ◽  
Rados Gajic ◽  
Stevan Djuric ◽  
Andreja Valcic
Keyword(s):  
Optical Properties ◽  
Single Crystals ◽  
Silicon Oxide ◽  
Critical Diameter ◽  
Lattice Parameters ◽  
Published Data ◽  
Czochralski Technique ◽  
Critical Rate ◽  
Bismuth Silicon Oxide ◽  
X Ray

Single crystals of Bi12SiO20 were grown by the Czochralski technique. The critical diameter and the critical rate of rotation were calculated. Suitable polishing and etching solutions were determined. X-Ray measurements were performed on powdered samples to obtain the lattice parameters. The optical properties of the bismuth silicon oxide single crystals were investigated. The obtained results are discussed and compared with published data.

Complex morphotropic domain structure and ferroelectric properties in high-TC single crystals of a ternary perovskite solid solution

2018 ◽  
Vol 6 (34) ◽  
pp. 9216-9223
Author(s):  
Zeng Luo ◽  
Nan Zhang ◽  
Zenghui Liu ◽  
Jian Zhuang ◽  
Jinyan Zhao ◽  
...  
Keyword(s):  
Solid Solution ◽  
Curie Temperature ◽  
Phase Boundary ◽  
Single Crystals ◽  
Monoclinic Phase ◽  
Ferroelectric Properties ◽  
Boundary Region ◽  
High Curie Temperature ◽  
High Tc ◽  
Domain Structures

Complex domain structures and monoclinic phase of the high Curie temperature (TC) BiScO3–Pb(Cd1/3Nb2/3)O3–PbTiO3 crystals in the morphotropic phase boundary region are investigated.

Spectral Absorption of Water Vapor and Carbon Dioxide Mixtures in the 2.7 Micron Band

1977 ◽  
Vol 99 (1) ◽  
pp. 53-59 ◽  
Author(s):  
K. Saido ◽  
W. H. Giedt
Keyword(s):  
Carbon Dioxide ◽  
Water Vapor ◽  
Optical Path Length ◽  
Black Body ◽  
Black Body Radiation ◽  
Wave Number ◽  
Published Data ◽  
Co2 Absorption ◽  
Spectral Absorption ◽  
Number Range

An investigation of the spectral absorption characteristics of water vapor and carbon dioxide mixtures in the 2.7 micron band is described. The absorption of black body radiation by gas mixtures in the central region of a high temperature furnace was measured. The optical path length of 30 cm was bounded by NaCl windows mounted in water-cooled holders. The temperature was essentially uniform in the central one-third of the test cell, and decreased to between 400 800 K at the ends. Representative spectral transmissivity distributions obtained for central temperatures ranging from 1000 to 2200 K and pressures from 0.25 to 3 atm for four different mixture ratios of water vapor and carbon dioxide are presented. Results showed the interaction effect on spectral transmissivity to be greatest at the band center where the maximum change from around 0.40 to 0.48 was observed for approximately equimolar mixtures at a total pressure of 0.5 atm. Since this occurs over a limited wave number range, spectral transmissivities of such mixtures can be acceptably approximated by ignoring the interaction. Spectral distributions predicted from published data for spectral H2O and CO2 absorption coefficients and line half-width to spacing ratios are in good agreement with measured distributions.

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