Тип публикации: статья из журнала

Год издания: 2017

Идентификатор DOI: 10.1016/j.solidstatesciences.2017.03.004

Ключевые слова: Entropy, Ferroelectric, Phase diagram, Phase transition, Thermal and dielectric properties

Аннотация: A study of heat capacity, thermal dilatation, permittivity, dielectric loops and susceptibility to hydrostatic pressure was carried out on quasi-ceramic samples of NH4HSO4 obtained from an aqueous solution as well as the melt. The main parameters of the successive P21/c (T1) - Pc (T2) - P1 phase transitions did not depend on the meПоказать полностьюthod of preparation of the samples, and were close to those determined in previous studies of single crystal and powder, except for the sign and magnitude of the baric coefficient for T2. Direct measurements of the pressure effect on the permittivity and thermal properties showed dT2/dp = ?123 K·GPa?1, which is consistent in terms of magnitude and sign with the baric coefficient evaluated using dilatometric and calorimetric data in the framework of the Clausius-Clapeyron equation. Thus, the temperature region of the ferroelectric Pc phase existence is extended under pressure. A strong decrease in the entropy jump at the Pc - P1 transformation with an increase in pressure, and the linear dependence of T2 on pressure, indicate that an increase in pressure shifts this phase transition towards the tricritical point on the T–p phase diagram. A significant barocaloric effect was found in the region of the Pc - P1 phase transition. © 2017 Elsevier Masson SAS

Журнал: Solid State Sciences

Выпуск журнала: Vol. 67

Номера страниц: 1-7

• Mikhaleva E.A. (Kirensky Institute of Physics, Federal Research Centre, KSC SB RAS, Krasnoyarsk, Russian Federation)
• Flerov I.N. (Kirensky Institute of Physics, Federal Research Centre, KSC SB RAS, Krasnoyarsk, Russian Federation, Siberian Federal University, Krasnoyarsk, Russian Federation)
• Kartashev A.V. (Kirensky Institute of Physics, Federal Research Centre, KSC SB RAS, Krasnoyarsk, Russian Federation, Astafijev Krasnoyarsk State Pedagogical University, Krasnoyarsk, Russian Federation)
• Gorev M.V. (Siberian Federal University, Krasnoyarsk, Russian Federation, Astafijev Krasnoyarsk State Pedagogical University, Krasnoyarsk, Russian Federation)
• Bogdanov E.V. (Kirensky Institute of Physics, Federal Research Centre, KSC SB RAS, Krasnoyarsk, Russian Federation, Krasnoyarsk State Agrarian University, Krasnoyarsk, Russian Federation)
• Bondarev V.S. (Kirensky Institute of Physics, Federal Research Centre, KSC SB RAS, Krasnoyarsk, Russian Federation, Siberian Federal University, Krasnoyarsk, Russian Federation)

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