Computer simulation of domain formation in crystals

Abstract

The phase transitions and the annealing processes simulated by the molecular-dynamics technique for KSCN and YBCO crystals are presented. The KSCN and YBCO model crystals show co-elastic and ferroelastic phase transitions, respectively. On quenching from disordered phases and subsequent annealing, tweed microstructures are obtained, which evolve to strip phases with well defined domain walls. In KSCN the antiphase boundaries are arbitrarily oriented.

A number of dielectric and ferroelastic crystals possess incommensurately modulated phases, which could be seen as a sequence of discommensuration planes. The same simulation technique has been used to study the nucleation of topological defects responsible for creation of discommensurations. It is proved that the elastic domain walls favour nucleation of discommensuration planes.

Key Words:

• Microstructure
• ferroelastic domains
• computer simulation