Li- and Mg-codoped bismuth niobate pyrochlores: Synthesis, structure, electrical properties
| Autor: | Tatyana A. Denisova, M.S. Koroleva, I. V. Piir, E. I. Istomina, N.A. Zhuravlev |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Materials science
Pyrochlore Analytical chemistry Ionic bonding chemistry.chemical_element 02 engineering and technology General Chemistry Atmospheric temperature range Conductivity engineering.material 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences 0104 chemical sciences Bismuth Dielectric spectroscopy chemistry engineering General Materials Science Lithium 0210 nano-technology Spectroscopy |
| Zdroj: | Solid State Ionics. 332:34-40 |
| ISSN: | 0167-2738 |
| DOI: | 10.1016/j.ssi.2018.12.017 |
| Popis: | The structure and conductivity of the new Li- and Mg-codoped bismuth niobates Bi1.5Mg1−xLixNb1.5O7−δ (0 ≤ x ≤ 0.50) with the pyrochlore structure have been investigated. The samples were synthesized by the method of organic-inorganic precursors combustion. A structural characterization was performed using 7Li nuclear magnetic resonance (NMR) spectroscopy in combination with the fitting of X-ray diffraction patterns. The Li+ cations dynamics were studied by temperature-dependent 7Li NMR lineshape analysis. The measurements have shown that the Li+ cations are distributed in one of two possible sublattices in the structure and are not mobile up to 120 °C. According to the results of structural analysis of the Bi1.5Mg1−xLixNb1.5O7−δ (x = 0.25; 0.50) pyrochlores the lithium atoms are distributed in the bismuth sites. The electrical properties were investigated by impedance spectroscopy method in the air, oxygen and “wet” atmospheres in the 25–750 °C temperature range. The activation energy value of dc conductivity is about 1.2–1.3 eV for the all samples and corresponds to the ionic (oxygen) conductivity at T > 400 °C. Electronic (p-type) conductivity was determined at T |
| Databáze: | OpenAIRE |
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