Polarization reversal in a perovskite ferroelectric by molecular-dynamics simulation

We characterize the microscopic processes that take place during polarization reversal in the tetragonal phase of a monodomain order-disorder perovskite ferroelectric using molecular-dynamics simulation. Microscopically the polarization of each unit cell reorients from an [001] orientation to an [001̄] orientation through intermediate states with polarization parallel to [011] and [011̄]. For low electric field and low temperature, chains of polarization reverse in a spatially coherent manner, resulting in macroscopic intermediate states with orthorhombic symmetry. At high electric field and high temperature the process is completely incoherent and there is no well-defined macroscopic intermediate state.