Effect of Semiconducting nature on the fracture behavior of Ferroelectric films.
BHARAT PENMECHA (California Institute of Techno), Kaushik Bhattacharya (California Institute of Technology)
Mechanics of Phase Transforming and Multifunctional Materials
Tue 9:00 - 10:30
CIT 219
Due to their impressive properties like high dielectric constants and switchable polarization, Ferroelectric perovskites have been used in a wide range of applications like capacitors, sensors, actuators and non-volatile memory devices. These materials are brittle in nature and are susceptible to developing cracks under the action of strong electro-mechanical fields that these applications typically involve. So understanding the fracture behavior of ferroelectric perovskites is of considerable importance. Traditionally while studying their fracture behavior, ferroelectric perovskites like Barium Titanate have been modeled as insulators. But in fact they are wide band-gap semiconductors with oxygen vacancies acting as dopants. Several experiments exist which point to fact that the semiconducting nature indeed plays a role in the overall response. Experiments carried out to understand the effect of external fields on crack propagation haven't produced consistent trends pertaining to variation of energy release rates with applied electric fields. Using a phase field model which incorporates semiconductor physics we simulate the domain formation around a stationary crack and explain the effect that semiconducting nature and diffusion of oxygen defects has on fracture behavior of single crystal ferroelectric films subject to electromechanical fields.