https://doi.org/10.1007/s100510050680
Structural study of the ferroelectric instability in Sn2P2Se6
1
CEMES-CNRS (UP -CNRS 8011) , B.P. 4347, 31055 Toulouse Cedex, France
2
Department of Physics and Chemistry of Solid State, Uzhgorod State
University, 294000 Uzhgorod Ukraine
3
Université de Ouagadougou, FAST,
Ouagadougou, Burkina
4
Université Toulon-Var, Bâtiment R, B.P. 132, 83957 La Garde Cedex, France
Received:
10
July
1998
Published online: 15 March 1999
The structural change occurring in Sn2P2Se6 between the paraelectric and the ferroelectric phases is investigated by means of X-ray diffraction. Details of the structure in both phases are obtained and the role of the Sn2+ lone pair is discussed in the light of structural data. In agreement with the 2/m to m symmetry lowering, polar displacements are found within the m plane away from a particular crystallographic direction but antiparallel displacements occur also. These results are discussed in the frame of the phenomenological theory which predicts a particular temperature dependence of the dielectric polarization in this crystal.
PACS: 61.10.Nz – Crystal structure solution and refinement techniques using X-rays / 64.70.Rh – Solid-solid transitions / 77.80.-e – Ferroelectricity and antiferroelectricity
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999
