Аннотация: The vibration frequencies of unstable ferroelectric and antiferrodistortion modes and the dependences of the energy on the ion displacement amplitude have been calculated within the generalized Gordon-Kim model for distortions along eigenvectors of these modes in the mixed compounds Sr(1-x)A(x)Ti(1-x/4)square O-x/4(3) and Sr(1-y)A(2y/3)square y/3TiO3 (A = Sc3+, In3+, La3+, Bi3+; square is the vacancy). To compensate an excess positive charge, vacancies are introduced into the Ti4+ or Sr2+ site. Calculations have been performed in the "average" crystal approximation for impurity concentrations of 0.25 and 0.50. To this end, a set of 40 atomic superlattices with various orderings of heterovalent ions Sr2+ and impurity A(3+) has been considered. It has been found that each impurity type, independently of charge balance, induces ferroelectric instabilities in doped compounds. In the case of doping with In3+ and La3+ for concentration x = 0.25, the possibility of rotating the polarization vector has been shown.
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Держатели документа:
[Zamkova, N. G.
Zhandun, V. S.
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 Science, Akademgorodok 50, Krasnoyarsk 660036, Russian Federation
Доп.точки доступа:
Zhandun, V. S.; Жандун, Вячеслав Сергеевич; Zinenko, V. I.; Зиненко, Виктор Иванович; Замкова, Наталья Геннадьевна