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Title: Crystal structure of the Ca{sub 3}TaGa{sub 3}Si{sub 2}O{sub 14} compound

Abstract

The absolute crystal structure of the Ca{sub 3}TaGa{sub 3}Si{sub 2}O{sub 14} piezoelectric compound is refined using X-ray diffraction analysis. The unit cell parameters and final R factors are as follows: a = 8.112(1) A, c = 4.9862(6) A, space group P321, Z = 1, R = 0.98%, and R{sub w} = 1.42%. It is shown that the configuration of the absolute crystal structure inherited from the seed material determines the positive sense of the optical activity of the crystal under investigation. The structural and acoustical characteristics of the Ca{sub 3}TaGa{sub 3}Si{sub 2}O{sub 14} crystals are compared with those of the La{sub 3}Ga{sub 5}SiO{sub 14} crystals.

Authors:
 [1]; ;  [2];  [1]; ;  [2];  [1]
  1. Moscow State University (Russian Federation)
  2. Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)
Publication Date:
OSTI Identifier:
21090953
Resource Type:
Journal Article
Resource Relation:
Journal Name: Crystallography Reports; Journal Volume: 52; Journal Issue: 2; Other Information: DOI: 10.1134/S1063774507020083; Copyright (c) 2007 Nauka/Interperiodica; Article Copyright (c) 2007 Pleiades Publishing, Inc; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CALCIUM COMPOUNDS; CRYSTALS; GALLIUM COMPOUNDS; OPTICAL ACTIVITY; OXIDES; PIEZOELECTRICITY; R FACTORS; SILICON COMPOUNDS; SPACE GROUPS; THALLIUM COMPOUNDS; TRIGONAL LATTICES; X-RAY DIFFRACTION

Citation Formats

Klimenkova, A. A., Maximov, B. A., E-mail: maximov@ns.crys.ras.ru, Molchanov, V. N., Mill', B. V., Rabadanov, M. H., Pisarevsky, Yu. V., and Pushcharovsky, D. Yu. Crystal structure of the Ca{sub 3}TaGa{sub 3}Si{sub 2}O{sub 14} compound. United States: N. p., 2007. Web. doi:10.1134/S1063774507020083.
Klimenkova, A. A., Maximov, B. A., E-mail: maximov@ns.crys.ras.ru, Molchanov, V. N., Mill', B. V., Rabadanov, M. H., Pisarevsky, Yu. V., & Pushcharovsky, D. Yu. Crystal structure of the Ca{sub 3}TaGa{sub 3}Si{sub 2}O{sub 14} compound. United States. doi:10.1134/S1063774507020083.
Klimenkova, A. A., Maximov, B. A., E-mail: maximov@ns.crys.ras.ru, Molchanov, V. N., Mill', B. V., Rabadanov, M. H., Pisarevsky, Yu. V., and Pushcharovsky, D. Yu. Thu . "Crystal structure of the Ca{sub 3}TaGa{sub 3}Si{sub 2}O{sub 14} compound". United States. doi:10.1134/S1063774507020083.
@article{osti_21090953,
title = {Crystal structure of the Ca{sub 3}TaGa{sub 3}Si{sub 2}O{sub 14} compound},
author = {Klimenkova, A. A. and Maximov, B. A., E-mail: maximov@ns.crys.ras.ru and Molchanov, V. N. and Mill', B. V. and Rabadanov, M. H. and Pisarevsky, Yu. V. and Pushcharovsky, D. Yu.},
abstractNote = {The absolute crystal structure of the Ca{sub 3}TaGa{sub 3}Si{sub 2}O{sub 14} piezoelectric compound is refined using X-ray diffraction analysis. The unit cell parameters and final R factors are as follows: a = 8.112(1) A, c = 4.9862(6) A, space group P321, Z = 1, R = 0.98%, and R{sub w} = 1.42%. It is shown that the configuration of the absolute crystal structure inherited from the seed material determines the positive sense of the optical activity of the crystal under investigation. The structural and acoustical characteristics of the Ca{sub 3}TaGa{sub 3}Si{sub 2}O{sub 14} crystals are compared with those of the La{sub 3}Ga{sub 5}SiO{sub 14} crystals.},
doi = {10.1134/S1063774507020083},
journal = {Crystallography Reports},
number = 2,
volume = 52,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}
  • The result of X-ray diffraction study on a single crystal of the calcium-gallogermanate family Ca{sub 3}TaGa{sub 3}Si{sub 2}O{sub 14} (CTGS) modulated by a surface acoustic wave (SAW) is presented. The power flow angle for SAW propagating along the X{sub 2} axis of the X-cut in CTGS was measured. The rocking curves for the CTGS crystal were recorded at different amplitudes of an input high frequency electric signal on interdigital transducer used to excite a SAW. Based on the data obtained, intensity dependence of diffraction satellites on the amplitude of electric signal exciting a SAW was built. Numerical simulation of themore » crystal rocking curves and dependence of diffraction satellite intensities on the SAW amplitude enabled the selection of a set of material constants at which the most complete coincidence of experimental and calculated results is observed.« less
  • An accurate X-ray diffraction study of Ca{sub 3}TaGa{sub 3}Si{sub 2}O{sub 14} single crystal has been performed using two datasets obtained on a diffractometer equipped with a CCD area detector (a = 8.1056(2) Å, c = 4.9800(1) Å, sp. gr. P321, Z = 1, R/wR = 0.486/0.488%). A model structure is determined which is characterized by a high degree of reproducibility of structural parameters. Each site in Ca{sub 3}TaGa{sub 3}Si{sub 2}O{sub 14} is occupied by atoms of only one type. Nevertheless, its structural feature is asymmetric disordering of sites of Ca, Ta, Ga, and two out of three oxygen atoms occupyingmore » special and general sites. A transition of some part of Ca atoms (~3%) from 3e sites on the twofold symmetry axis to general 6g sites is revealed.« less
  • An accurate X-ray diffraction study of Sr{sub 3}TaGa{sub 3}Si{sub 2}O{sub 14} (STGS) crystal (a = 8.3023(10) Angstrom-Sign , c = 5.0853(2) Angstrom-Sign , sp. gr. P321, Z = 1, R/wR = 0.59/0.52%, 4004 independent reflections) is performed. The use of two independent data sets obtained on diffractometers with point and 2D detectors made it possible to determine the model structure characterized by the best reproducibility of parameters. The ordered distribution of atoms over crystallographic positions and the anharmonic character of displacements of all cations and one oxygen atom are established.
  • We have grown a new langasite-type piezoelectric single crystal Sr{sub 3}TaGa{sub 3}Si{sub 2}O{sub 14} (STGS) with dimensions of 15 mm in diameter and 30 mm in length by using the Czochralski technique. The X-ray powder diffraction (XRPD) of single crystal was performed at room temperature. The thermal expansion coefficient perpendicular to Z direction has been measured as 3.2x10{sup -6} K{sup -1} between 343.15 and 493.15 K, and along Z-axis, 9.7x10{sup -6} K{sup -1} between 318.15 and 503.15 K. The specific heat of the crystal has been measured as 0.68 J g{sup -1} K{sup -1} at 468.15 K. The transmittance spectramore » from 200 to 3200 nm annealed in different atmospheres were measured.« less
  • The absolute crystal structures of two enantiomorphic forms of the Ca{sub 3}Ga{sub 2}Ge{sub 4}O{sub 14} crystals (a = 8.075(1) A, c = 4.9723(6) A, space group P321) with the positive and negative senses of the optical activity are determined using X-ray diffraction analysis. The final R factors are as follows: R = 1.75% and R{sub w} = 2.57% for the crystal with the positive sense of the optical activity and R = 1.86% and R{sub w} = 2.78% for the crystal with the negative sense of the optical activity. The replacement of the Ca{sup 2+} ions by larger Sr{sup 2+}more » ions (with the formation of the Sr{sub 3}Ga{sub 2}Ge{sub 4}O{sub 14} compound) leads to an anisotropic expansion of the crystal lattice (with a more considerable increase in the lattice parameter a as compared to the lattice parameter c), a change in the occupation of the 1a and 3f positions by the Ga{sup 3+} and Ge{sup 4+} ions, and symmetrization of the octahedra and tetrahedra forming the structural framework. The shape of the dodecahedron changes so that its size along the polar electric axis 2 increases significantly. This change is the main factor responsible for the increase in the piezoelectric activity of the Sr{sub 3}Ga{sub 2}Ge{sub 4}O{sub 14} compound as compared to the piezoelectric activity of the Ca{sub 3}Ga{sub 2}Ge{sub 4}O{sub 14} compound.« less