Dynamical behavior of the phase transition of epitaxial BaTiO_3 from atomistic simulations

M. SEPLIARSKY, S. TINTE

PHYSICA B - CONDENSED MATTER

ELSEVIER SCIENCE BV

Año: 2009 vol. 404 p. 2730 - 2732

0921-4526

Using an atomistic shell model we study the temperature dependence of the ferroelectric properties of BaTiO3 under biaxial compressive strain applicable to growth on perovskites substrate. Moleculardynamics simulations show a r -> c -> p sequence of phase transitions when temperature isincreased, and the absence of an ac phase. The first-order paraelectric-to-ferroelectric phasetransition presents in bulk changes to a second-order one as a consequence of the in-plane constraintimposed by the mechanical boundary conditions. From the tetragonal ferroelectric c phase, thetransition takes place in a fnite range of temperature where the lattice parameter normal to the planekeeps approximately constant until Tc is reached. Analysis of the local polarization behavior reveals anorder–disorder dynamics as the dominant mechanism of the transition.