In-situ electron microscopy exploration of structural dynamics in ferroelectric materials

主講人：陳子斌 香港理工大學助理教授

時間：2024年10月28日10：00

地點：數(shù)理學院十號樓222室

舉辦單位：數(shù)理學院

主講人介紹：2017年畢業(yè)于澳大利亞悉尼大學。他主要利用先進電子顯微學技術(shù)研究先進鐵電功能材料以及增材制造金屬材料的基礎(chǔ)科學與工程問題。陳子斌博士在新材料成分設計、微結(jié)構(gòu)表征、力學性能測試等方面擁有良好的科研基礎(chǔ)。陳子斌博士的研究團隊先后承擔多個國際化基金項目，其中包括澳大利亞研究協(xié)會基金項目（Australian Research Councile），美國海軍實驗室全球計劃基金項目（United State of America Office of Naval Research Global），香港研究資助局（Hong Kong Research Grant Council），中國國家自然科學基金（National Natural Science Foundation of China） 獲得資金共計超過500萬元。陳子斌博士在多個國際期刊，包括Nature, Nature Materials, Science Advances, Nature Communications, Physical Review Letters, Materials Today, Acta Materialia， Additive Manufacturing，以及Materials Research Letters發(fā)表了多篇高水平論文。陳子斌博士現(xiàn)擔任國際學術(shù)期刊《Microstructures》以及《Materials Research Letters》青年編委，同時擔任多個學術(shù)期刊的審稿人，包括《Nature Communications》，《Physical Review Letters》，《Advanced Functional Materials》等。曾獲得香港理工大學青年創(chuàng)新研究獎 (2022), Ross Coffin Purdy Award (美國陶瓷協(xié)會) (2020), 以及中國優(yōu)秀自費留學生 (2018)等榮譽。

內(nèi)容介紹：Understanding ferroelectric domain switching behavior under external stimuli is crucial for the application of ferroelectrics in memories, actuators, and nanoelectronic devices. Ferroelectric behavior is characterized by detecting the value of remanent polarization and switchable and non-switchable polarization in a polarization-electric field hysteresis loop. This can be measured using a ferroelectric properties measurement instrument. However, quantitative data on these parameters do not provide information on microstructural mechanisms. Conventional ex-situ transmission electron microscopy (TEM) has been widely used to explore the microstructures of ferroelectric materials before and after domain switching under external stimuli. However, it does not provide information on the dynamic processes of behavior. With recent advancements in characterization techniques, it is now possible to conduct in-situ microscopy investigations of ferroelectric materials under mechanical and/or electrical loading. In this presentation, we will demonstrate how to combine state-of-the-art in-situ and ex-situ TEM techniques to investigate ferroelectric behavior and understand the relationships between local atomic scale structure and properties. We reveal that specific domain switching behaviors are linked to combined intrinsic and extrinsic properties, including phases, structures, compositions of materials, type of external stimuli (mechanical loading, electrical loading, electrical radiation), and material dimensions. These domain switching behaviors lead to many fascinating and novel structures, including nano twins assisting domain switching processes and charged domain walls providing local conductivity. These results open new doors for understanding the mechanisms behind ferroelectric properties and serve as guidance for designing the next generation of high-performance ferroelectric materials.