Рубрики:
STATISTICAL-MECHANICS
PEROVSKITES
CRYSTALS
ORDER
RELAXOR
BATIO3
PBTIO3
Кл.слова (ненормированные):
Crystal lattices -- Ferroelectricity -- Lattice vibrations -- Solids -- Ferroelectric (barium strontium titanate) -- Ferroelectric phase transitions -- Lattice (CO) -- Lattice dynamics -- Vibration spectrum -- Ferroelectric materials
STATISTICAL-MECHANICS
PEROVSKITES
CRYSTALS
ORDER
RELAXOR
BATIO3
PBTIO3
Кл.слова (ненормированные):
Crystal lattices -- Ferroelectricity -- Lattice vibrations -- Solids -- Ferroelectric (barium strontium titanate) -- Ferroelectric phase transitions -- Lattice (CO) -- Lattice dynamics -- Vibration spectrum -- Ferroelectric materials
Аннотация: The lattice vibration spectra, rf permittivity, and dynamic Born charges of disordered PbB(1/2)'B(1/2)'' O(3) (B' = Ga, In, Lu; B '' = Nb, Ta) solid solutions are calculated in terms of the generalized Gordon-Kim model. All the compounds are found to have soft modes related to the center (Gamma(15)) and boundary point R (R(15)) of the Brillouin zone; the frequencies of these modes are close. The ferroelectric phase transition temperatures and the spontaneous polarization in the ferroelectric phase are calculated for the solid solutions using a model Hamiltonian in the local mode approximation and the Monte Carlo method. These temperatures for the tantalum compounds are found to be higher than for the niobium compounds, and temperature t(s) increases with the atomic number of ion B'. A model where the antiferroelectric state is related to the condensation of modes Gamma(15) and R(15) is proposed. It is found that, for all compounds except for PbSc(1/2)Nb(1/2)O(3) and PbSc(1/2)Ta(1/2)O(3), the ferroelectric phase, which is only related to the condensation of mode R(15), and the antiferroelectric phase have similar energies. In PbIn(1/2)Ta(1/2)O(3), the antiferroelectric phase turns out to be energetically favorable.
WOS,
Scopus,
Для получение полного текста обратитесь в библиотеку
Держатели документа:
[Zhandun, V. S.
Zamkova, N. G.
Zinenko, V. I.] Russian Acad Sci, LV Kirensky Phys Inst, Siberian Branch, Krasnoyarsk 660036, Russia
ИФ СО РАН
Kirensky Institute of Physics, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk 660036, Russian Federation
Доп.точки доступа:
Zamkova, N. G.; Замкова, Наталья Геннадьевна; Zinenko, V. I.; Зиненко, Виктор Иванович; Жандун, Вячеслав Сергеевич