skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Distribution, structures and nonlinear properties of noncentrosymmetric niobates and tantalates

Abstract

The distribution of 117 noncentrosymmetric niobates and tantalates over different crystal systems and types of space formation of Nb, Ta-O polyhedrons have been revealed. The dependence of polyhedron space formation in the crystal lattice of the compound on stoichiometric concentration (SC) of niobium and tantalum is established. Individual Nb, Ta-O octahedrons are found for SC=19-7.5, and chains and layers of the octahedrons appear in the range SC=11.0-5.2. Only frame formations of Nb, Ta-O octahedrons are possible under SC<5.2.

Authors:
 [1];  [2]
  1. Laboratory of Optical Materials and Structures, Institute of Semiconductor Physics, SB RAS, Novosibirsk, 630090 (Russian Federation). E-mail: antonis_chem@mail.ru
  2. Laboratory of Optical Materials and Structures, Institute of Semiconductor Physics, SB RAS, Novosibirsk, 630090 (Russian Federation)
Publication Date:
OSTI Identifier:
20784971
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 179; Journal Issue: 4; Other Information: DOI: 10.1016/j.jssc.2006.01.019; PII: S0022-4596(06)00010-7; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CRYSTAL LATTICES; CRYSTALS; DISTRIBUTION; LAYERS; NIOBATES; STOICHIOMETRY; TANTALATES

Citation Formats

Korotkov, A.S., and Atuchin, V.V. Distribution, structures and nonlinear properties of noncentrosymmetric niobates and tantalates. United States: N. p., 2006. Web. doi:10.1016/j.jssc.2006.01.019.
Korotkov, A.S., & Atuchin, V.V. Distribution, structures and nonlinear properties of noncentrosymmetric niobates and tantalates. United States. doi:10.1016/j.jssc.2006.01.019.
Korotkov, A.S., and Atuchin, V.V. Sat . "Distribution, structures and nonlinear properties of noncentrosymmetric niobates and tantalates". United States. doi:10.1016/j.jssc.2006.01.019.
@article{osti_20784971,
title = {Distribution, structures and nonlinear properties of noncentrosymmetric niobates and tantalates},
author = {Korotkov, A.S. and Atuchin, V.V.},
abstractNote = {The distribution of 117 noncentrosymmetric niobates and tantalates over different crystal systems and types of space formation of Nb, Ta-O polyhedrons have been revealed. The dependence of polyhedron space formation in the crystal lattice of the compound on stoichiometric concentration (SC) of niobium and tantalum is established. Individual Nb, Ta-O octahedrons are found for SC=19-7.5, and chains and layers of the octahedrons appear in the range SC=11.0-5.2. Only frame formations of Nb, Ta-O octahedrons are possible under SC<5.2.},
doi = {10.1016/j.jssc.2006.01.019},
journal = {Journal of Solid State Chemistry},
number = 4,
volume = 179,
place = {United States},
year = {Sat Apr 15 00:00:00 EDT 2006},
month = {Sat Apr 15 00:00:00 EDT 2006}
}
  • The difference has been revealed between the statistical distributions of centrosymmetric and noncentrosymmetric titanates over crystal symmetry systems. Space formations of Ti-O polyhedra has been analyzed for 52 noncentrosymmetric titanates. The type of Ti-O polyhedra space formations is dependent on the stoichiometric ratio, SR = n(O)/n(Ti), where n(O) is the number of oxygen and n(Ti) is the number of titanium atoms in formal composition of the compound. Individual (Ti-O) polyhedra are found for SR {>=} 3.5 (SR {>=} 6 for octahedra), chains and layers of the polyhedra exist in the range stoichiometric ratio, SR = 3.5-7.0. Only framework formations aremore » possible at SR {<=} 3.5.« less
  • Three-component systems of lead and alkaline-earth niobates were prepared, replacing partially the niobium by tantalum, in order to establish the influence of the replacement on the ferroelectric properties of the system. The general composition of the solid solutions is given by the formulas: (Pb/sub 0.5/ Ba/sub 0.1/Sr/sub 0.4/ (Nb/sub 1-/ >i/sub x/Ta/sub x/)/sub 2/O/sub 6/ and (Pb/ sub 0./ /sub 6/Ba/sub 0./ /sub 2/Ca/sub 0./ /sub 2/) (Nb/sub 1-x/Ta/sub x/ >i)/ sub 2/O/sub 6/, using Ba, Ca, and Sr carbonates, PbO, and Nb/sub 2/O/sub 5/ and Ta/sub 2/O/sub 5/ as raw materials. The usual ceramic preparative methods were employed, firingmore » the compounds containing large amounts of tantalum under an inert atmosphere. X-ray diffraction studies of the systems showed that their structure is similar to that of the orthorhombic lead niobate. In view of this and of the near-identity of the ionic diameters of Nb/sup 5+/ and of Ta/sup 5+/, it could not be established with certainty whether the systems were solid solutions or heterogeneous mixtures. No hysteresis loops were observed at liquid nitrogen temperatures with materials having relaxation properties, not even with systems with an x value?0.3 which presented such loops at room temperature, which may be explained by the increase of the coercive field at low temperatures. The replacement of niobium by tantalum led first to a weakening of the ferroelectric properties, followed by emergence of relaxation properties. (TTT)« less