THE INFLUENCE OF FLEXOELECTRIC EFFECT ON THE DOMAIN STRUCTURE AND FRACTURE TOUGHNESS OF FERROELECTRIC MATERIALS
Yangqin GuoGrand Ballroom A
Due to the impressive electromechanical properties, ferroelectric materials are widely used in actuators, memory devices and other electronic devices. However, the instinct weak strength and brittleness of ferroelectrics make it easy to failure under external force and electric field. Furthermore, giant strain gradient will be generated near the crack tip with the action of external forces. As a consequence, flexoelectricity is expected to sharply affect the domain configuration and local electromechanical behavior. In this work, the time-dependent Ginzburg-Landau (TDGL) theory and phase field model are used to study the influence of flexoelectric effect on the domain structure and fracture toughness of PbTiO3 in the vicinity of the crack tip. The results show that flexoelectric effect reduces the fracture toughness near the crack tip and breaks the symmetry of the domain structure and fracture toughness. Fracture toughness of parallel to the polarization direction decreases more than that perpendicular to the polarization direction. Compared with anti-parallel to the polarization direction, the flexoelectric effect is more likely to weaken the fracture toughness of parallel to the polarization direction. As a conclusion, flexoelectric electric effect is vatal influence on the reliability design of ferroelectric materials and devices.