Phase transitions and thermodynamic properties of (NH4)(3)VO2F4 cryolite

Описание

Тип публикации: статья из журнала

Год издания: 2009

Идентификатор DOI: 10.1016/j.solidstatesciences.2008.11.004

Ключевые слова: Oxyfluorides, Phase transition, Calorimetry, Phase diagram, Ferroelectricity, Halide minerals, Phase diagrams, Sugar (sucrose), Thermodynamic properties, Calorimetric measurements, Cubic phase, First-order phase transitions, Heat capacities, Phase transition temperatures, Pressure dependences, Structural transformations, Temperature ranges, Phase transitions

Аннотация: Calorimetric measurements performed in a wide temperature range on (NH4)(3)VO2F4 have shown the presence of four heat capacity anomalies at T-1 = 438 K, T-2 = 244 K, T-3 = 210.2 K, T-4 = 205.1 K associated with the first order phase transitions. In accordance with the permittivity behavior, the structural transformations are of nonПоказать полностьюferroelectric nature. Pressure dependence of the phase transition temperatures has been studied by DTA under pressure. The entropy of phase transitions is analyzed mainly in the framework of the orientational disordering of NH4+ and VO2F43- ions in a cubic phase. (C) 2008 Elsevier Masson SAS. All rights reserved.

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Издание

Журнал: SOLID STATE SCIENCES

Выпуск журнала: Vol. 11, Is. 4

Номера страниц: 836-840

ISSN журнала: 12932558

Место издания: AMSTERDAM

Издатель: ELSEVIER SCIENCE BV

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