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Title:Manipulating ferroelectric domain structures via external stimulation – an in-situ transmission electron microscopy investigation

Time: Dec. 28th, 3:00 pm, 新学科M楼,314

Presenter:Prof. Xiaozhou Liao, School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Australia. Email: xiaozhou.liao@sydney.edu.au

Abstract:Ferroelectrics results from the displacement of ions that leads to spontaneous polarization with the internal electric field pointing towards a specific direction in materials. A region with the same polarization direction is called a ferroelectric domain. Understanding ferroelectric domain switching behaviour under external stimuli is extremely important for the applications of ferroelectrics in memories, actuators and nanoelectronic devices. In this seminar, I will present our recent in-situ transmission electron microscopy investigation results on how separate and combined mechanical and electrical loadings affect ferroelectric domain structures and how a high-energy electron beam can lead to local accumulation of trapped charges that determine local domain configurations. Our results show that mechanical confinement during electrical loading adds one more degree of freedom for domain manipulation, which would provide an appealing possibility for significantly improving ferroelectric device performance, and that a high-energy electron beam can be used to precisely and reversibly control ferroelectric nano-domain morphology for memory storage devices. We also propose a method that overcomesthe time-dependent ferroelectric backswitching problem in memory applications.

Brief bio:Dr. Xiaozhou Liao is a full professor in the University of Sydney, Australia. He conducted his postgraduate research in the School of Physics, University of Sydney and received his PhD degree in 2000. He moved to USA taking up a Director Funded Postdoctoral Fellowship in Los Alamos National Laboratory in 2001 and was a research scientist in the University of Chicago from 2004 to 2006. He returned to Sydney as a lecturer in the School of Aerospace, Mechanical and Mechatronic Engineering in June 2006.

Dr. Liao's research interest focuses on the structures and structure–property relationships of advanced structural and functional materials using ex-situ and in-situ electron microscopy techniques. He has published more than 210 papers in journals including Nature Materials, Nature Communications, Physical Review Letters, and Acta Materialia. His papers have been collectively cited > 8,300 times with an h-index of 48 (data from Web of Science).