Тип публикации: статья из журнала
Год издания: 2008
Идентификатор DOI: 10.1134/S1063783408110280
Ключевые слова: 61; 50; Ks; 65; 40; Ba; 65; 40; gd; 78; 30; Hv; 81; 30; Dz
Аннотация: Elpasolite Rb2KTiOF5 (space group, Fm was synthesized using a solid-phase reaction method. The temperature dependences of the heat capacity, the unit cell parameters, the structure, the permittivity, the response to an external pressure, and the Raman spectra were studied. A nonferroelectric phase transition was revealed at T (0) =Показать полностью215 K; the transition is accompanied by a tetragonal distortion of the unit cell (space group I4/m, Z = 10) and a change in the entropy (S (0) = Rln8), which is anomalously large for perovskite-like oxyfluorides with atomic cations. The specific features of the mechanism of structure distortion are discussed in combination with the previous experimental data obtained for cryolite (NH4)(3)TiOF5 and elpasolite Rb2KGaF6.
Журнал: PHYSICS OF THE SOLID STATE
Выпуск журнала: Vol. 50, Is. 11
Номера страниц: 2175-2183
ISSN журнала: 10637834
Место издания: NEW YORK
Издатель: MAIK NAUKA/INTERPERIODICA/SPRINGER