Electron diffraction study of crystal structures of (Sr1−xBax)2Nb2O7
| Autor: | Shinya Tsukada, Masami Terauchi, Kenji Tsuda, Bikas Aryal, Daisuke Morikawa, Yukikuni Akishige |
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| Rok vydání: | 2019 |
| Předmět: |
Materials science
Physics and Astronomy (miscellaneous) Doping 02 engineering and technology Crystal structure Electron Atmospheric temperature range 021001 nanoscience & nanotechnology 01 natural sciences Crystallography Electron diffraction Lattice (order) 0103 physical sciences General Materials Science Dielectric anomaly 010306 general physics 0210 nano-technology |
| Zdroj: | Physical Review Materials. 3 |
| ISSN: | 2475-9953 |
| DOI: | 10.1103/physrevmaterials.3.044405 |
| Popis: | Selected-area electron diffraction and convergent-beam electron diffraction (CBED) techniques are used to reveal the Ba doping effect on the crystal structure of (${\mathrm{Sr}}_{1\ensuremath{-}x}{\mathrm{Ba}}_{x}{)}_{2}{\mathrm{Nb}}_{2}{\mathrm{O}}_{7}$ [SBN(x)] in the temperature range from 293 to 693 K. Ba doping of ${\mathrm{Sr}}_{2}{\mathrm{Nb}}_{2}{\mathrm{O}}_{7}$ (SN) causes weakening of the incommensurate modulation and deviation from the C-centered lattice. On the other hand, symmetries of fundamental reflections in CBED patterns of SBN(x) are seen to be the same as those of SN, showing a small structural deviation from Cmc${2}_{1}$. Crystal symmetries above and below the temperature of a relaxorlike dielectric anomaly in SBN ($x=0.32$) at 465 K remain unchanged. CBED experiments with a nanometer-sized electron probe do not show any indication of the presence of a nanodomain around this temperature. However, the presence of a few-micron-sized polar-inversion domains is found at around 573 K in SBN ($x=0.32$). The origin of the reported relaxorlike dielectric anomaly in SBN ($x=0.32$) is discussed on the basis of the experimental results of CBED. |
| Databáze: | OpenAIRE |
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