Thermal, dielectric and barocaloric properties of NH4HSO4 crystallized from an aqueous solution and the melt
URI (for links/citations):http://www.sciencedirect.com/science/article/pii/S1293255816308196
Mikhaleva, E. A.
Flerov, I. N.
Kartashev, A. V.
Gorev, M. V.
Bogdanov, E. V.
Bondarev, V. S.
Институт инженерной физики и радиоэлектроники
Базовая кафедра физики твердого тела и нанотехнологий
Journal Name:Solid State Sciences
Journal Quartile in Scopus:Q2
Journal Quartile in Web of Science:Q2
Bibliographic Citation:Mikhaleva, E. A. Thermal, dielectric and barocaloric properties of NH4HSO4 crystallized from an aqueous solution and the melt [Текст] / E. A. Mikhaleva, I. N. Flerov, A. V. Kartashev, M. V. Gorev, E. V. Bogdanov, V. S. Bondarev // Solid State Sciences. — 2017. — Т. 67. — С. 1-7
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) 4 Pc (T2) 4 P1 phase transitions did not depend on the method 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 ¼ 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 4 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 Tep phase diagram. A signiﬁcant barocaloric effect was found in the region of the Pc 4 P1 phase transition.