Detection of Negative Thermal Expansion in a Single Crystal of Sr0.75Ba0.25Nb6O2 Relaxor Ferroelectric by X-Ray Diffraction Analysis
| Autor: | Alexander P. Dudka |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Diffraction
Materials science Condensed matter physics 02 engineering and technology 021001 nanoscience & nanotechnology 010403 inorganic & nuclear chemistry 01 natural sciences 0104 chemical sciences Surfaces Coatings and Films Negative thermal expansion Electrical resistance and conductance Lattice (order) Goniometer X-ray crystallography Thin film 0210 nano-technology Single crystal |
| Zdroj: | Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques. 14:574-577 |
| ISSN: | 1819-7094 1027-4510 |
| DOI: | 10.1134/s1027451020030234 |
| Popis: | The atomic structure of a single crystal of Sr0.75Ba0.25Nb6O2 representing a relaxor ferroelectric is determined from X-ray diffraction data. At nine temperatures within a range of 93–480 K, 12 experiments are performed. The experimental facilities (area detector, goniometer, and sample cooling system) are calibrated. The region of negative thermal expansion with respect to the unit-cell parameter с is revealed at 272–324 K. In the same region, an electrical resistance anomaly is observed. It is found that the structural parameters have a singularity at 296 K, in particular, an unusual thermal motion of atoms is observed. This correlates with a kink in the resistance–temperature curve at 297.5 K. The obtained results and analysis of published data indicate that, near room temperature, several physical properties of Sr0.75Ba0.25Nb6O2 relaxor at once have singularities, which can be explained by the revealed lattice instability. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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