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Structure Sequence in the CaTiO 3 –LaAlO 3 Microwave Ceramics—Revised
Author(s) -
Khalyavin Dmitry D.,
Salak Andrei N.,
Senos Ana M. R.,
Mantas Pedro Q.,
Ferreira Victor M.
Publication year - 2006
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2006.00929.x
Subject(s) - perovskite (structure) , octahedron , materials science , microwave , ceramic , crystallography , diffraction , crystal structure , phase (matter) , discontinuity (linguistics) , phase transition , powder diffraction , x ray crystallography , analytical chemistry (journal) , mineralogy , chemistry , condensed matter physics , metallurgy , physics , mathematics , optics , mathematical analysis , organic chemistry , chromatography , quantum mechanics
The composition‐induced crystal structure transformations in the (1− x )CaTiO 3 – x LaAlO 3 microwave ceramics were studied by X‐ray powder diffraction. Increasing LaAlO 3 content results in two‐phase transitions: Pnma → Imma (0.4< x <0.5) and Imma → R 3 c (0.5< x <0.6), which are related to changes of the octahedral tilting: a − b + a − → a − b 0 a − and a − b 0 a − → a − a − a − , respectively. The compositional variation of the parameters of the primitive perovskite unit cell is consistent with a continuous character of the Pnma → Imma phase transition. In the case of the Imma → R 3 c crossover, a discontinuity in the variation is observed.