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

主讲人：陈子斌 香港理工大学助理教授

时间：2024年10月28日10：00

地点：数理学院十号楼222室

举办单位：数理学院

主讲人介绍：2017年毕业于澳大利亚悉尼大学。他主要利用先进电子显微学技术研究先进铁电功能材料以及增材制造金属材料的基础科学与工程问题。陈子斌博士在新材料成分设计、微结构表征、力学性能测试等方面拥有良好的科研基础。陈子斌博士的研究团队先后承担多个国际化基金项目，其中包括澳大利亚研究协会基金项目（Australian Research Councile），美国海军实验室全球计划基金项目（United State of America Office of Naval Research Global），香港研究资助局（Hong Kong Research Grant Council），中国国家自然科学基金（National Natural Science Foundation of China） 获得资金共计超过500万元。陈子斌博士在多个国际期刊，包括Nature, Nature Materials, Science Advances, Nature Communications, Physical Review Letters, Materials Today, Acta Materialia， Additive Manufacturing，以及Materials Research Letters发表了多篇高水平论文。陈子斌博士现担任国际学术期刊《Microstructures》以及《Materials Research Letters》青年编委，同时担任多个学术期刊的审稿人，包括《Nature Communications》，《Physical Review Letters》，《Advanced Functional Materials》等。曾获得香港理工大学青年创新研究奖 (2022), Ross Coffin Purdy Award (美国陶瓷协会) (2020), 以及中国优秀自费留学生 (2018)等荣誉。

内容介绍：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.