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Crystal Structure of the Layered Perovskite-Like Srn(Nb,Ti)nO3n+2 Compounds. Part II. TEM Study of the Srn(Nb,Ti)nO3n+2
Published
Author(s)
Igor Levin, Leonid A. Bendersky, Terrell A. Vanderah
Abstract
Series of Srn(Nb,Ti)nO3n+2 structures with n=4,4.5,5,6 and 7 were studies by transmission electron microscopy. These structures are composed of inifite two-dimensional slabs of the distorted perovskite structure that are n' (Ti,Nb)O6 octahedra thick and extend parallel to the (110)p( p' refers to cubic perovskite) plane. The slabs are displaced with respect to each other with a 1/2[011]p translation vector. The structures with n=4,5,6 and 7 were shown to undergo commensurate->incommensurate phase transition on cooling at temperatures ranging from 150oC to 250oC. The n-5 incommensurate phase further transformed at T=180 to the monoclinic structure with the space group P112l/b. For n=4, 6 and 7 structures no lock-in transition was observed down to -170oC. For the compound with n=4.5 the transition from orthorhombic to monoclinic structure (P1121/b) occurred on cooling at T=390oC. All these transitions in Srn(Nb,Ti)nO3n+2 compounds were attributed to the tilting of (Nb,Ti)O6 octahedra.
Levin, I.
, Bendersky, L.
and Vanderah, T.
(2008),
Crystal Structure of the Layered Perovskite-Like Sr<sub>n</sub>(Nb,Ti)<sub>n</sub>O<sub>3n+2</sub> Compounds. Part II. TEM Study of the Sr<sub>n</sub>(Nb,Ti)<sub>n</sub>O<sub>3n+2</sub>, Acta Crystallographica Section B-Structural Science
(Accessed November 8, 2024)