Understanding the Mechanism of Ferroelectric Phase Transition in RbHSO4: A High-Pressure Raman Investigation
| Autor: | Gopal K. Pradhan, Diptikanta Swain, Venkata Srinu Bhadram, Chandrabhas Narayana |
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| Rok vydání: | 2020 |
| Předmět: |
Diffraction
Phase transition Condensed matter physics 010405 organic chemistry Crystal structure Dielectric 010402 general chemistry 01 natural sciences Ferroelectricity Rubidium hydrogen sulfate 0104 chemical sciences Ion Inorganic Chemistry Condensed Matter::Materials Science chemistry.chemical_compound symbols.namesake chemistry symbols Physical and Theoretical Chemistry Raman spectroscopy |
| Zdroj: | Inorganic Chemistry. 59:7960-7965 |
| ISSN: | 1520-510X 0020-1669 |
| Popis: | Previous high-pressure dielectric and diffraction studies on rubidium hydrogen sulfate (RbHSO4) observed ferroelectric phase transition below 1 GPa pressure. We have performed high-pressure Raman spectroscopy studies on RbHSO4 up to a maximum pressure of 5.15 GPa and at ambient temperature to understand the microscopic origin and mechanism of ferroelectric transition. On the basis of the pressure dependence of Raman mode frequencies and their full-width at half-maxima, we observed a transition around a pressure of 0.3 GPa, similar to the ferroelectric transition discovered in dielectric measurements, followed by another transition around 2.4 GPa. These phase transitions are evident from the appearance/disappearance of Raman-active modes and the change in the slope of frequencies with pressures. From the pressure dependence of the S-O and S-OH frequencies, we deduce that HSO4- ion ordering results in ferroelectric phase transition around 0.3 GPa. Further, the transition around 2.4 GPa pressure is associated with significant changes in the stretching and bending vibrational frequencies and indicates a structural phase transition with possible lowering of the crystal symmetry. Interestingly, no significant changes are observed in the Raman spectrum around 1 GPa, at which a phase transition was noticed in earlier X-ray and dielectric studies. |
| Databáze: | OpenAIRE |
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