Thermal, structural, optical, dielectric and barocaloric properties at ferroelastic phase transition in trigonal (NH4)2SnF6: A new look at the old compound
URI (for links/citations):http://elib.sfu-kras.ru/handle/2311/33175
Flerov, Igor N.
Kartashev, Andrey V
Gorev, Mikhail V.
Bogdanov, Evgeniy V.
Mel’Nikova, Svetlana V.
Molokeev, Maxim S.
Pogoreltsev, Evgeniy I.
Laptash, Natalia M.
Институт инженерной физики и радиоэлектроники
Journal Name:Journal of Fluorine Chemistry
Journal Quartile in Scopus:Q2
Journal Quartile in Web of Science:Q2
Bibliographic Citation:Flerov, Igor N. Thermal, structural, optical, dielectric and barocaloric properties at ferroelastic phase transition in trigonal (NH4)2SnF6: A new look at the old compound [Текст] / Igor N. Flerov, Andrey V Kartashev, Mikhail V. Gorev, Evgeniy V. Bogdanov, Svetlana V. Mel’Nikova, Maxim S. Molokeev, Evgeniy I. Pogoreltsev, Natalia M. Laptash // Journal of Fluorine Chemistry. — 2016. — Т. 183. — С. 1-9
Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.
Structural phase transition P-3m1 ↔ P-1 of the first order and nonferroelectric nature was found in (NH4)2SnF6 at about 110 K in the process of thermal, optical, dielectric and X-ray studies. Order-disorder transformation is accompanied by large changes of entropy (ΔS0 = 16.4 J/mol•K) and volume (ΔV0/V ≈ 1 %). The structural model associated with three orientations of NH4 tetrahedra in P-3m1 phase and their complete ordering in P-1 phase was suggested with the entropy change (ΔS0 = 18.3 J/mol•K) close to the experimental value. A good agreement between baric coefficients measured in a direct way (dT0/dp = -157 K/GPa) and evaluated using entropy and volume changes at phase transition (- 170 K/GPa) was found. Barocaloric effects in (NH4)2SnF6 are comparable with those of known solid state refrigerants and are characterised by a low-pressure need for realising their maximum values.