Ferroelectric properties of Ba_<i>x</i>Sr_{1 <i>x</i>}TiO₃solid solutions obtained by molecular dynamics simulation

Abstract

Classical shell-model potentials for describing the complex ferroelectric behaviour of barium titanate and strontium titanate are developed and used to simulate BaxSr1−xTiO3 solid solutions. The temperature versus composition phase diagram is very well described and the local behaviour of the structure and polarization is analysed. It is shown that the ferroelectric properties of the solid solution can be understood in terms of the effects of average density and the local chemical environment. The experimentally observed static dielectric peak broadening around Tc at low x is reproduced in the simulation and seems to be related to the average volume rather than to the local chemical environment.