دورية أكاديمية
First-principles calculations of the high-temperature phase transformation in yttrium tantalate
| العنوان: | First-principles calculations of the high-temperature phase transformation in yttrium tantalate |
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| المؤلفون: | Feng, Jing, Shian, Samuel, Xiao, Bing, Clarke, David R. |
| المصدر: | Quick submit: 2014-09-08T10:26:30-04:00 Feng, Jing, Samuel Shian, Bing Xiao, and David R. Clarke. 2014. “First-Principles Calculations of the High-Temperature Phase Transformation in Yttrium Tantalate.” Physics Review B 90, no. 9: 094102. |
| بيانات النشر: | American Physical Society (APS), 2014. |
| سنة النشر: | 2014 |
| المجموعة: | FAS Scholarly Articles |
| الوصف: | The high-temperature phase transition between the tetragonal (scheelite) and monoclinic (fergusonite) forms of yttrium tantalite (YTaO4 ) has been studied using a combination of first-principles calculations and a Landau free-energy expansion. Calculations of the Gibbs free energies show that the monoclinic phase is stable at room temperature and transforms to the tetragonal phase at 1430 °C, close to the experimental value of 1426±7 °C. Analysis of the phonon modes as a function of temperature indicate that the transformation is driven by softening of transverse acoustic modes with symmetry Eu in the Brillouin zone center rather than the Raman-active Bg mode. Landau free-energy expansions demonstrate that the transition is second order and, based on the fitting to experimental and calculated lattice parameters, it is found that the transition is a proper rather than a pseudoproper type. Together these findings are consistent with the transition being ferroelastic. Engineering and Applied Sciences |
| نوع الوثيقة: | Journal Article |
| اللغة: | English |
| تدمد: | 1098-0121 |
| العلاقة: | Physical Review B |
| DOI: | 10.1103/PhysRevB.90.094102 |
| الوصول الحر: | http://nrs.harvard.edu/urn-3:HUL.InstRepos:12965656Test |
| حقوق: | Jing Feng, Samuel Shian, Bing Xiao and David R. Clarke |
| رقم الانضمام: | edshld.1.12965656 |
| قاعدة البيانات: | Digital Access to Scholarship at Harvard (DASH) |
| تدمد: | 10980121 |
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| DOI: | 10.1103/PhysRevB.90.094102 |