Out-of-centre distortions around an octahedrally coordinated Ti4+ in BaTiO3

Manuel Gaudon (1)

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux

The prototypical ferroelectric system BaTiO3 is an oxide with a perovskite-type structure that exhibits a textbook example of multiple phase transitions associated with an out-of-centre distortion of the octahedral Ti4+ cations. This research combines the double-well potentials model and the bond valence model, to provide an explanation for the cubic–tetragonal–orthorhombic–rhombohedric phase transition sequence. It is shown that to consider the atomic displacements can only occur in the strict respect of their valence, which is calculated with the bond valence model, is sufficient to lead to the clear prediction of the whole transition sequence.

Mots clés: Bond valence; Thermodynamics; BaTiO3; Perovskite; Phase transitions

Domaines: Matériaux

Manuel Gaudon. Out-of-centre distortions around an octahedrally coordinated Ti4+ in BaTiO3. Polyhedron, 2015, 88, pp.6-10. ⟨10.1016/j.poly.2014.12.004⟩. ⟨hal-01112286⟩