[행사/세미나] [Colloquium] Oct. 26(Wed.) Atomic-scale observation of structural phase transition of strontium ferrite
- 물리학과
- 조회수2984
- 2022-10-22
이번 학기 콜로퀴움은 코로나19 재유행 대비 상황에 따라 온-오프 하이브리드(오프라인+Real Time Streaming)으로 운영될 예정입니다.
여섯 번째 강연에는 경북대학교 강경태 교수님을 모시고 콜로퀴움을 개최하오니, 학과 구성원 여러분의 많은 참여를 부탁 드립니다.
아 래
1. Title: Atomic-scale observation of structural phase transition of strontium ferrite
2. Speaker: 강 경 태 교수님 (경북대학교, '08학부, '11대학원 동문)
3. Date & Time: Oct. 26(Wed.) 2022. 4:30 PM
4. Place: Natural Science 1, Room No. 31214
5. Abstract: Brownmillerite oxides have been actively explored owing to the peculiar structure changes called a topotactic phase transition, where oxygen removal/addition happens along with a minimal volume change. Since the topotactic phase transition typically accompanies the transition of properties in transport or magnetism, providing an avenue for tailoring the facile functionalities, e.g., neuromorphic memory device. However, it is tricky to directly observe the atomic-scale image of the migration of ions resulting in the transition, so the transition mechanism remains elusive. Here we look into an atomic-scale operando observation of topotactic phase transformation from the perovskite SrFeO3 to brownmillerite SrFeO2.5 caused by oxygen vacancy.[1] During the phase transition, oxygen vacancy formation, migration, and order were studied through quantitative analyses of oxygen intensity and cation sublattice movement at the atomic scale. Our operando high-resolution transmission electron microscopy (HRTEM) observation, in conjunction with density functional theory (DFT) calculation, unravels the oxygen migration pathway responsible for the collective lattice dynamic motion.
[1] Y. Xing et al., Matter 5, 3009 (2022).