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Relationship Between the Orthorhombic and Hexagonal Phases in Dy 2 TiO 5
Author(s) -
Seymour Kevin C.,
Ribero Daniel,
McCormack Scott J.,
Kriven Waltraud M.
Publication year - 2016
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/jace.14354
Subject(s) - orthorhombic crystal system , thermal expansion , hexagonal crystal system , crystallography , phase (matter) , materials science , hexagonal phase , negative thermal expansion , crystal structure , diffraction , atom (system on chip) , phase transition , chemistry , condensed matter physics , metallurgy , optics , physics , organic chemistry , computer science , embedded system
The thermal expansion of Dy 2 TiO 5 in the hexagonal phase was evaluated and compared with the orthorhombic phase using in situ high‐temperature X‐ray diffraction. The crystal structure, volume changes before and after the transformation process, as well as the mechanism behind the thermal expansion behavior was determined and proposed. It was found that in the hexagonal phase, the thermal expansion was caused by the oxygen anions in the axial positions of the trigonal bipyramidal structure moving toward the central Ti atom. While expanding, the movement of these oxygen anions slows the expansion along the c ‐axis resulting in a decrease in α 33 with temperature. Furthermore, a structural relationship between the orthorhombic and the hexagonal phases was proposed.