Home > 게시판 > 세미나
Oak Ridge National Laboratory의 최우석 박사님을 초빙하여 아래와 같이 특별세미나를 개최합니다.
학과 구성원 여러분의 많은 참석을 부탁 드립니다.
1. 일시: 2012년 10월 8일(월) 16:30
2. 장소: 물리학과 세미나실 (제1과학관 31355호실)
3. 초청연사: 최 우 석 박사님 (Oak Ridge National Laboratory)
4. 제목: Versatile Spin State Transitions in Multivalent ACoOx Epitaxial Thin Films
5. 초록: Cobalt-based transition metal oxides exhibit a wide spectrum of physical properties owing to the multivalent nature of cobalt. Multiple d-electrons in cobalt ions are highly susceptible to a small deviation in the surrounding environment, such as strain-induced structural change or oxygen stoichiometry, which yields various electronic and magnetic ground states. In this talk, I will focus on our recent studies on ACoOx epitaxial thin films, which serve as an important model system in understanding the role of cobalt ion and related physical phenomena.
In the first part, strain-induced spin states in stoichiometric LaCoO3 thin films will be demonstrated . I will show that the ferroelastic LaCoO3 thin film adopts epitaxial strain in a unique way, exhibiting an unconventional strain relaxation mechanism. This strain relaxation behavior further resulted in modification of cobalt spin states, shedding light onto the mysterious ferromagnetic ground state of LaCoO3 thin films. In the second part of the talk, topotactic phase transformation and subsequent physical property changes in SrCoOx epitaxial thin films will be discussed . In particular, the two end members of SrCoOx: SrCo3+O2.5 and SrCo4+O3.0 showed drastically different electronic and magnetic ground states. Moreover, owing to the multivalent nature of cobalt, these two considerably different phases could be reversibly transformed from one to the other at relatively low temperatures. The simple and fast topotactic transformation turned out to be useful for many technological applications utilizing oxygen ion transport of cobalt-based transition metal oxides, including solid oxide fuel cells and electrochemical sensors.
 W. S. Choi, J.-H. Kwon, H. Jeen, J. E. Hamann-Borrero, A. Radi, S. Macke, R. Sutarto, F. He, G. A. Sawatzky, V. Hinkov, M. Kim, and H. N. Lee, Nano Lett. published online at http://pubs.acs.org/doi/abs/10.1021/nl302562f (2012).
 H. Jeen, W. S. Choi, M. D. Biegalski, I. C. Tung, J. W. Freeland, D. Shin, H. Ohta, M. F. Chisholm, & H. N. Lee, under review.
|공지||2021학년도 1학기 콜로퀴움 일정||2021.01.13||32145|
|공지||<12/8(Thu.) 11:00am>노벨상 소개 강연 - 2016년 노벨 물리학상: 위상 응집 물리의 탄생||2016.11.28||641561|
|642||<April 28(Wed.)> 손에 잡히는 AI||2021.04.21||10|
|641||<April 21(Wed.)> 우주배경복사 편광 관측 - 남극점 기지 바이셉/켁 어레이(BICEP/Keck Array) 망원경||2021.04.12||169|
|640||<April 7(Wed.)> Mid-scale facilities for condensed matter research: high magnetic field and neutron scattering||2021.03.31||463|
|639||<Mar.24(Wed.)> A tale of quantum magnets||2021.03.18||756|
|638||<Mar.31(Wed.)> Nonlinear nanophotonics using on-chip microring resonator||2021.03.25||771|
|637||<Mar.17(Wed.)> Glue spectrum for superconductivity obtained via optical spectroscopy||2021.03.10||1039|
|636||<Mar.10(Wed.)> Dark matter searches in neutrino detectors||2021.03.04||1970|
|635||<Mar.3(Wed.)>Scaling laws in Natural Language Processing||2021.02.25||2166|
|634||<Feb.18(Thu.)> Hund's metallicity in the vicinity of a Van Hove singularity / Correlated topological phases in strongly correlated heterostructures||2021.02.16||2226|
|633||<Jan.28(Thu.)>X-ray Absorption Spectroscopy Study of Amorphous Oxide Thin Films||2021.01.27||2232|
|632||<Jan.14(Thu.)>Oxygen sponge effects for epitaxial manganite thin film design||2021.01.11||3299|
|631||<Dec.9(Wed.)>한국형 암흑물질 실험||2020.12.02||3522|
|630||<Dec.2(Wed.)>The era of gravitational waves, and the science that makes it possible||2020.11.25||4154|
|629||<Oct.14(Wed.)>New Ways to Search for the Dark World||2020.10.12||4231|
|628||<Sep.23(Wed.)>나는 내 마음이야||2020.09.16||4925|
|627||<11/5(Thu.)> Higher Spin Cooper Pairs||2020.10.27||5085|
|626||<Oct.28(Wed.)> Physics of Global Warming||2020.10.22||5462|
|625||<Nov.18(Wed.)>When Physics meets the Living Cells||2020.11.11||5483|
|624||<Nov.4(Wed.)>Progresses in Elucidating the Optoelectronic Properties of Perovskite Semiconductor||2020.10.28||5711|
|623||<8/1(Sat.)> Recent Advances in Deep Learning||2020.07.29||6221|