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New insights into BaTi 1– x Sn x O 3 (0 ≤ x ≤ 0.20) phase diagram from neutron diffraction data
Author(s) -
Veselinović Ljiljana,
Mitrić Miodrag,
Avdeev Maxim,
Marković Smilja,
Uskoković Dragan
Publication year - 2016
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s1600576716013157
Subject(s) - neutron diffraction , tetragonal crystal system , crystallography , materials science , differential scanning calorimetry , analytical chemistry (journal) , phase diagram , rietveld refinement , phase transition , x ray crystallography , phase (matter) , barium titanate , dielectric , ferroelectricity , crystal structure , powder diffraction , barium , space group , diffraction , chemistry , physics , optics , condensed matter physics , thermodynamics , optoelectronics , organic chemistry , chromatography , metallurgy
Neutron powder diffraction (NPD) was employed to further investigate the BaTi 1− x Sn x O 3 (BTS) system previously studied by X‐ray diffraction. The room‐temperature phase compositions and crystal structures of BTS samples with x = 0, 0.025, 0.05, 0.07, 0.10, 0.12, 0.15 and 0.20 were refined by the Rietveld method using NPD data. It is well known that barium titanate powder ( x = 0) crystallizes in the tetragonal P 4 mm space group. The crystal structures of the samples with 0.025 ≤ x ≤ 0.07 were refined as mixtures of P 4 mm and Amm 2 phases; those with x = 0.1 and 0.12 show the coexistence of rhombohedral R 3 m and cubic phases, while the samples with x = 0.15 and 0.20 crystallize in a single cubic phase. Temperature‐dependent NPD was used to characterize the BaTi 0.95 Sn 0.05 O 3 sample at 273, 333 and 373 K, and it was found to form single‐phase Amm 2, P 4 mm and structures at these respective temperatures. The NPD results are in agreement with data obtained by differential scanning calorimetry and dielectric permittivity measurements, which show a paraelectric–ferroelectric transition (associated with structural transition) from to P 4 mm at about 353 K followed by a P 4 mm to Amm 2 phase transition at about 303 K.