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Mel’Nikova, Svetlana V.
Bogdanov, Evgeniy V.
Molokeev, Maxim S.
Laptash, Natalia M.
Flerov, Igor N.
2020-01-20T07:56:35Z
2020-01-20T07:56:35Z
2019
Mel’Nikova, Svetlana V. Optical and calorimetric studies of K2TaF7 [Текст] / Svetlana V. Mel’Nikova, Evgeniy V. Bogdanov, Maxim S. Molokeev, Natalia M. Laptash, Igor N. Flerov // Journal of Fluorine Chemistry. — 2019.
00221139
https://www.sciencedirect.com/science/article/pii/S0022113919300302?via%3Dihub
http://elib.sfu-kras.ru/handle/2311/129262
Optical and calorimetric experiments on K2TaF7 are performed in a wide temperature range. No features were found in the behavior of the birefringence Δnb(T), the angle of rotation of the indicatrix ϕ(T) and the heat capacity ΔCp(T) except for those associated with the Pnma↔P21/c phase transition. Structural transformation was characterized as strong first order “proper” ferroelastic accompanied by a huge angle ϕ ≈40° and strong pretransition phenomena in Δnb(T). Two contributions to the anomalies of the optical properties were found associated with the photoelastic effect and the transition parameter related linearly to the spontaneous deformation. Thermal treatments cause correlated changes in temperature and enthalpy of the phase transition, which leads to the invariance of the large magnitude of the corresponding entropy ΔS=22 J/mol·K which does not match the model with the absence of structural disorder in the Pnma phase.
Optical and calorimetric studies of K2TaF7
Journal Article
Journal Article Preprint
29.19.15
2020-01-20T07:56:35Z
10.1016/j.jfluchem.2019.04.016
Институт инженерной физики и радиоэлектроники
Кафедра теплофизики
Базовая кафедра физики твердого тела и нанотехнологий
Journal of Fluorine Chemistry
Q2
Q3


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