Тип публикации: статья из журнала
Год издания: 2019
Идентификатор DOI: 10.1134/S106378341911026X
Ключевые слова: lattice dynamics, structural instability, ab initio calculations, phase transitions
Аннотация: The frequencies of lattice vibrations in the RFe3(BO3)(4) (R = Pr, Nd, Tb, Dy, or Ho) crystals in the high-temperature R32 phase and their temperature dependence have been calculated using the quasi-harmonic approximation. It has been found that, at the boundary point Lambda of the Brillouin zone, the frequency of the unstable vibrПоказать полностьюation mode the structural phase transition R32 -> P3(1)21 is related to strong changes with temperature in the TbFe3(BO3)(4), DyFe3(BO3)(4), and HoFe3(BO3)(4) crystals. With increasing temperature, the frequency of the soft mode stabilizes and takes a real value. No significant changes in the phonon spectra, including the boundary point Lambda, with increasing temperature for the PrFe3(BO3)(4) and NdFe3(BO3)(4) crystals have been observed.
Журнал: PHYSICS OF THE SOLID STATE
Выпуск журнала: Vol. 61, Is. 11
Номера страниц: 2019-2025
ISSN журнала: 10637834
Место издания: MOSCOW
Издатель: PLEIADES PUBLISHING INC