logo

korean english

게시판

Home > 게시판 > 세미나

Oak Ridge National Laboratory의 최우석 박사님을 초빙하여 아래와 같이 특별세미나를 개최합니다.

학과 구성원 여러분의 많은 참석을 부탁 드립니다. 

         아             래  

     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 [1]. 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 [2]. 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.

 

[1] 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).
[2] 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.

번호 제목 날짜 조회 수
공지 2021학년도 1학기 콜로퀴움 일정 2021.01.13 32110
공지 <12/8(Thu.) 11:00am>노벨상 소개 강연 - 2016년 노벨 물리학상: 위상 응집 물리의 탄생 2016.11.28 641475
280 <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
279 <Jan.28(Thu.)>X-ray Absorption Spectroscopy Study of Amorphous Oxide Thin Films 2021.01.27 2230
278 <Jan.14(Thu.)>Oxygen sponge effects for epitaxial manganite thin film design 2021.01.11 3295
277 <11/5(Thu.)> Higher Spin Cooper Pairs 2020.10.27 5079
276 <8/1(Sat.)> Recent Advances in Deep Learning 2020.07.29 6216
275 <12/10(Tue.)> Investigating dark matter signals at neutrino telescopes 2019.12.06 21612
274 <12/17(Tue.)> Nuclear spectroscopy with low energy reaction thermal neutrons in ILL 2019.12.17 22539
273 <12/6(Fri.)>topological phase transitions in Kitaev quantum spin liquids. 2019.12.04 22711
272 <2/17(Mon.)> Magneto-optical study of the Dirac semimetal Cd3As2 in Voigt geometry 2020.02.11 23306
271 <10/1(Tue.) Mini-Workshop on BSM Physics with Neutrino Detectors 2019.09.30 24898
270 <9/24(Tue) 4:00 pm ~ > Structure Formation with Two Periods of Inflation: Beyond plain LCDM 2019.09.17 27320
269 <8/30(Fri) 16:00 ~ >Structures of light neutron-rich nuclei, 17,19C 2019.08.22 27770
268 <11/12(Mon.) 3:30pm>Dark Matter Probes with Astrophysical Observations 2018.11.05 28447
267 <8/26(Mon) 14:00 ~ >Constructing viable models of bouncing scenarios 2019.08.20 28505
266 [8/1(Wed.), 8/2(Thu)] Lectures on gravitational waves 2018.07.24 28507
265 <8/24(Fri.) 3:30pm>Secret interactions of light sterile neutrinos with the DSNB 2018.08.21 28600
264 <8/19(Mon) 13:30 ~ >Detection of cosmic rays in the PeV to EeV energy range file 2019.08.16 28602
263 <7/11(Wed.) 3:00pm> Traversable wormholes: two-dimensional example 2018.07.09 28714
262 <12/20(Thu) 2:00pm> Gravitating Spinning Stars (a particle theorist's perspective) 2018.12.17 28765
261 <8/23(Thu.) 2:00pm>What will we do with near-term quantum computers? 2018.08.17 28879