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Title: Electrical properties and water incorporation in A-site deficient perovskite La{sub 1−x}Ba{sub x}Nb{sub 3}O{sub 9−0.5x}

Abstract

Barium doped A-site deficient perovskites La{sub 1−x}Ba{sub x}Nb{sub 3}O{sub 9−0.5x} (x=0–0.05) were synthesized by the solid state method, their structure, electrical properties and state of oxygen-hydrogen groups have been investigated. These phases were found to be able to incorporate water from the gas phase and to exhibit proton transport. Hydration is accompanied by the formation of different forms of oxygen-hydrogen groups: OH{sup −} – groups and H{sub 3}O{sup +} – ions. The total conductivities of doped samples increased in a wet atmosphere due to the appearance of proton current carriers (at the temperatures below 700 °C), but the conductivity increased insignificantly (~0.25 order of magnitude) because of a low doping level and, consequently, small concentration of protons. TG-measurements confirmed relatively low water content (below 0.2%). The total conductivity depends substantially on x and exhibits a minimum on σ−f(x) dependencies. It has been suggested that such behavior is a manifestation of a mixed cation effect. - Highlights: • Barium doped perovskites La{sub 1−x}Ba{sub x}Nb{sub 3}O{sub 9−0.5x} (x=0–0.05) are capable to incorporate water from the gas phase and to exhibit proton transport. • The hydration is accompanied by the formation of OH{sup −} – groups and H{sub 3}O{sup +} – ions. •more » The total conductivity exhibits a minimum on σ−f(x) dependencies as a result of a mixed cation effect.« less

Authors:
 [1];  [2];  [1]
  1. Institute of Natural Sciences, Ural Federal University, 19 Mira Street, Ekaterinburg (Russian Federation)
  2. Laboratory SPMS Structures, Properties and Modeling of Solids, Ecole CentraleSupélec, Grande Voie des Vignes, Châtenay-Malabry, 92290 Paris (France)
Publication Date:
OSTI Identifier:
22584114
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 238; Other Information: Copyright (c) 2016 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:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; BARIUM; BARIUM COMPLEXES; CATIONS; CONCENTRATION RATIO; DOPED MATERIALS; ELECTRICAL PROPERTIES; HUMIDITY; HYDRATION; HYDROGEN; LANTHANUM COMPLEXES; NIOBIUM OXIDES; OXONIUM IONS; OXYGEN; PEROVSKITE; PROTON TRANSPORT; PROTONS; RAMAN SPECTROSCOPY; SOLIDS; WATER

Citation Formats

Animitsa, I., E-mail: irina.animitsa@urfu.ru, Iakovleva, A., and Belova, K. Electrical properties and water incorporation in A-site deficient perovskite La{sub 1−x}Ba{sub x}Nb{sub 3}O{sub 9−0.5x}. United States: N. p., 2016. Web. doi:10.1016/J.JSSC.2016.03.023.
Animitsa, I., E-mail: irina.animitsa@urfu.ru, Iakovleva, A., & Belova, K. Electrical properties and water incorporation in A-site deficient perovskite La{sub 1−x}Ba{sub x}Nb{sub 3}O{sub 9−0.5x}. United States. doi:10.1016/J.JSSC.2016.03.023.
Animitsa, I., E-mail: irina.animitsa@urfu.ru, Iakovleva, A., and Belova, K. Wed . "Electrical properties and water incorporation in A-site deficient perovskite La{sub 1−x}Ba{sub x}Nb{sub 3}O{sub 9−0.5x}". United States. doi:10.1016/J.JSSC.2016.03.023.
@article{osti_22584114,
title = {Electrical properties and water incorporation in A-site deficient perovskite La{sub 1−x}Ba{sub x}Nb{sub 3}O{sub 9−0.5x}},
author = {Animitsa, I., E-mail: irina.animitsa@urfu.ru and Iakovleva, A. and Belova, K.},
abstractNote = {Barium doped A-site deficient perovskites La{sub 1−x}Ba{sub x}Nb{sub 3}O{sub 9−0.5x} (x=0–0.05) were synthesized by the solid state method, their structure, electrical properties and state of oxygen-hydrogen groups have been investigated. These phases were found to be able to incorporate water from the gas phase and to exhibit proton transport. Hydration is accompanied by the formation of different forms of oxygen-hydrogen groups: OH{sup −} – groups and H{sub 3}O{sup +} – ions. The total conductivities of doped samples increased in a wet atmosphere due to the appearance of proton current carriers (at the temperatures below 700 °C), but the conductivity increased insignificantly (~0.25 order of magnitude) because of a low doping level and, consequently, small concentration of protons. TG-measurements confirmed relatively low water content (below 0.2%). The total conductivity depends substantially on x and exhibits a minimum on σ−f(x) dependencies. It has been suggested that such behavior is a manifestation of a mixed cation effect. - Highlights: • Barium doped perovskites La{sub 1−x}Ba{sub x}Nb{sub 3}O{sub 9−0.5x} (x=0–0.05) are capable to incorporate water from the gas phase and to exhibit proton transport. • The hydration is accompanied by the formation of OH{sup −} – groups and H{sub 3}O{sup +} – ions. • The total conductivity exhibits a minimum on σ−f(x) dependencies as a result of a mixed cation effect.},
doi = {10.1016/J.JSSC.2016.03.023},
journal = {Journal of Solid State Chemistry},
number = ,
volume = 238,
place = {United States},
year = {Wed Jun 15 00:00:00 EDT 2016},
month = {Wed Jun 15 00:00:00 EDT 2016}
}
  • Tetragonal tungsten bronze (TBB) type niobium compounds Sr{sub 6}Nb{sub 10}O{sub 30} and a solid solution series Ba{sub 6{minus}x}La{sub x}Nb{sub 10}O{sub 30} (x = 0, 1, 2, 3) were synthesized and their resistivity was measured in the temperature range 10--300 K. The Sr compound is a semiconductor, the high temperature data (100 {le} T {le} 300 K) for which can be fitted to the T{sup {minus}1/4} law. Ba{sub 6}Nb{sub 10}O{sub 30} also is a semiconductor, but with a different temperature dependency. La-substitution in the Ba compound caused a conduction mechanism to change from semiconducting (x = 0) to metallic (x {ge}more » 1).« less
  • Oxides belonging to the families Ba{sub 3}ZnTa{sub 2-x}Nb{sub x}O{sub 9} and Ba{sub 3}MgTa{sub 2-x}Nb{sub x}O{sub 9} were synthesized by the solid state reaction route. Sintering temperatures of 1300 deg. C led to oxides with disordered (cubic) perovskite structure. However, on sintering at 1425 deg. C hexagonally ordered structures were obtained for Ba{sub 3}MgTa{sub 2-x}Nb{sub x}O{sub 9} over the entire range (0{<=}x{<=}1) of composition, while for Ba{sub 3}ZnTa{sub 2-x}Nb{sub x}O{sub 9} the ordered structure exists in a limited range (0{<=}x{<=}0.5). The dielectric constant is close to 30 for the Ba{sub 3}ZnTa{sub 2-x}Nb{sub x}O{sub 9} family of oxides while the Mg analoguesmore » have lower dielectric constant of {approx}18 in the range 50 Hz to 500 kHz. At microwave frequencies (5-7 GHz) dielectric constant increases with increase in niobium concentration (22-26) for Ba{sub 3}ZnTa{sub 2-x}Nb{sub x}O{sub 9}; for Ba{sub 3}MgTa{sub 2-x}Nb{sub x}O{sub 9} it varies between 12 and 14. The 'Zn' compounds have much higher quality factors and lower temperature coefficient of resonant frequency compared to the 'Mg' analogues.« less
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