Тип публикации: статья из журнала
Год издания: 2004
Идентификатор DOI: 10.1134/1.1830662
Ключевые слова: 61.50.Ks, 71.27.+a, 71.30.+h, 81.40.Tv
Аннотация: The optical properties and structure of gadolinium iron borate GdFe3(BO3)4 crystals are studied at high pressures produced in diamond-anvil cells. X-ray diffraction data obtained at a pressure of 25.6 GPa reveal a firstorder phase transition retaining the trigonal symmetry and increasing the unit cell volume by 8%. The equation of Показать полностьюstate is obtained and the compressibility of the crystal is estimated before and after the phase transition. The optical spectra reveal two electronic transitions at pressures ~26 GPa and ~43 GPa. Upon the first transition, the optical gap decreases jumpwise from 3.1 to ~2.25 eV. Upon the second transition at P=43 GPa, the optical gap deceases down to ~0.7 eV, demonstrating a dielectric-semiconductor transition. By using the theoretical model developed for a FeBO3 crystal and taking into account some structural analogs of these materials, the anomalies of the high-pressure optical spectra are explained.
Журнал: JETP Letters
Выпуск журнала: Т. 80, № 6
Номера страниц: 426-432
ISSN журнала: 00213640
Место издания: Москва
Издатель: Pleiades Publishing, Ltd. (Плеадес Паблишинг, Лтд)