Impact of interface misfit strain on the movement and tilt angles of the domain wall in ferroelectric thin films

The effect of interface misfit strain on the movement and tilt angles of the domain wall in ferroelectric thin film is investigated with a multicoupling finite element model. Since this theoretical model is developed based on the phase field method and is solved using the finite element method, it can effectively predict the electromechanical coupling behavior of materials that have complicated boundary conditions. The simulated results demonstrate that the position, tilt angles, strain gradient and energy density of the domain wall can be modulated by misfit compressive strain at the interface of ferroelectric nanostructures. A larger interface misfit compressive strain will lead to the movement of domain wall towards the direction which allows the a domain to possess a larger volume. The difference of the tilt angles of domain walls on both sides of the a domain becomes larger as the interface misfit strain increases, implying a transition of the shape of the a domain from parallelogram to wedge.