Nanomechanics of Ferroelectric Fractures: Phase-Field Simulations and Piezoresponse Force Microscopy Characterizations

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The research objective of this grant is to elucidate the fracture of ferroelectrics, a complicated process that involves interplay between crack propagation and ferroelectric domain switching at nanometer scale. A computational phase-field method will be developed to simulate crack propagation and domain switching in ferroelectrics, and piezoresponse force microscopy will be applied for in-situ observation of such microstructure evolution in ferroelectrics under electrical, mechanical, and thermal loadings. These two techniques will be combined to investigate the fracture behavior of various ferroelectric crystals and ceramics, enabling direct comparison between computational simulations and microscopic characterization at a length scale that is most relevant to the underlying physical processes.Ferroelectrics is an important class of technological materials that are widely used as sensors, actuators, capacitors, and nonvolatile memories, and many of their applications depend on ferroelectric domain switching triggered by external fields. Ferroelectric fracture process is closely coupled with domain switching, and has important influences on the failure of ferroelectric devices. The project will shed insight on the complicated fracture processes in ferroelectric materials that is not well understood, and will help improve the performance and reliability of ferroelectric devices and systems. The project will also train graduate and undergraduate students, improve graduate and undergraduate curriculums, and offer outreach activities for K-12 school teachers and students.