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Phase-field Simulation of Pressure-induced Mechanical Switching in Nanoscale Oxide Thin Film

October 13, 2017 | 11 a.m.-12:30 p.m.
Nedderman Hall 229 | Seminar Flyer

Seminar Speaker

Ye Cao, Ph.D.

Assistant Professor, Materials Science and Engineering, UTA

Abstract

Functional materials such as ferroelectric oxides underpin a vast spectrum of modern technological applications such as nonvolatile memories, piezoelectric actuators/sensors, and dielectric/ferroelectric capacitors. A fundamental understanding of the microstructural evolutions in nanoscale functional oxide, such as ion motion, ferroelectric domain switching and phase transition, and their couplings with thermal, electrical, mechanical and chemical excitations are fundamental to the realization of many of its application. In this talk I will demonstrate a mesoscale computational approach based on phase-field model to study the pressure-induced polarization switching in ferroelectric thin films. Compared to conventional bias-induced polarization switching, pressure switching has emerged as a powerful method for domain patterning, with the advantage of highly localized, electrically erasable and electric damage free characteristics. However, the mechanisms for pressure induced polarization switching in ferroelectrics remain highly controversial, with flexoelectricity, polarization rotation and suppression, and bulk and surface electrochemical processes all being potentially relevant. Here I will show how phase-field model can be used to classify these different mechanisms in mechanical switching in a prototypical lead zirconate titanate thin film. The implication of this example, as well as the potential application of the established mesoscale model will be discussed to provide insights for the future design and optimization of functional materials.

Bio

Ye Cao is an assistant professor in UTA's Department of Materials Science and Engineering. Before joining UTA he was a postdoctoral research associate in the Center of Nanophase Materials Sciences at Oak Ridge National Laboratory. He earned his Ph.D. in materials science and engineering from Pennsylvania State University in 2014. His research interests include mesoscale phase-field simulations on the microstructural evolutions and applications in functional oxides and energy-materials, such as transport dynamics and resistance degradation in dielectric capacitors, domain switching and phase transition in ferroelectric thin film, and electric, elastic and chemical coupling in nanoscale functional oxides.