Coupled displacive and order-disorder dynamics in LiNbO ₃ by molecular-dynamics simulation

The phase transition behavior of LiNbO _3xwas investigated. The molecular dynamics simulations were used to study the ferroelectric-paraelectric phase transition of the compound. It was observed that the phase transition of NiNbO ₃ was a two-stage process, which involved a order-disorder transition in the Li-O planes at the Curie temperature and displacive transition in the Nb-O cages at a temperature below Curie temperature. The effect of high-temperature structure on the dynamical response of the transition was also discussed.