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 <12/8(Thu.) 11:00am>노벨상 소개 강연 - 2016년 노벨 물리학상: 위상 응집 물리의 탄생 2016.11.28 1058360
542 <May.23(Wed.) 4:30 PM> 한국 희귀동위원소과학 프로젝트(Rare Isotope Science Project in Korea) 2018.05.16 45823
541 <May.16(Wed.) 4:30 PM> Single crystal growth of metal film and metal oxide film on different substrates and their various applications 2018.05.09 87780
540 <May.9(Wed.) 4:30 PM> "How gold was produced in the universe?" 2018.05.02 81526
539 <May.2(Wed.) 4:30 PM> Machine learning and statistical physics 2018.04.23 72723
538 <April.18(Wed.) 4:30 PM>금속의'블랙스완' 2018.04.11 43864
537 <April.11(Wed.) 4:30 PM>History of Superconductivity and its Future 2018.04.04 48553
536 <April.4(Wed.) 4:30 PM>From Static to Dynamic Multiferroics 2018.03.29 72040
535 <Mar.28(Wed.) 4:30 PM>우주의 번개와 천둥 2018.03.27 44676
534 <3/16(Fri.)11:00> Superlattice phonons of two dimensional heterostructures 2018.03.16 76801
533 <Mar.21(Wed.) 4:30 PM>깊은 땅속 중성미자 실험, DUNE 2018.03.14 45868
532 <Mar.7(Wed.) 4:30 PM>Acoustic metamaterial: principles and applications of phononic crystals 2018.03.02 45028
531 <3/2(Fri.)11:00>Evolving magnetic interactions near a Kondo breakdown 2018.02.27 64016
530 2018학년도 1학기 콜로퀴움 일정 2018.01.03 109999
529 <Dec.13(Wed.) 4:30 PM>기본에 충실하고 새로움에 도전한다 - 자율주행자동차의 핵심 기술들 – 2017.12.07 54459
528 <Dec.6(Wed.) 4:30 PM> 실험핵천체물리학: 과거와 미래(Experimental Nuclear Astrophysics: Past and Future) 2017.11.29 45189
527 <Nov.29(Wed.) 4:30 PM> The Intensity Frontier Experiment & SHiP 2017.11.22 45863
526 <Nov.22(Wed.) 4:30 PM> Dark Side of the Universe 2017.11.15 66245
525 <Nov.15(Wed.) 4:30 PM> Mixed metal oxide films for energy and memory device applications 2017.11.08 59998
524 <Nov. 8(Wed.) 4:30 PM> 연성물질 기반 위상학적 결함구조의 상전이와 응 2017.11.01 105590
523 <Nov. 1(Wed.) 4:30 PM> 광자와 이온트랩을 이용한 양자 정보처리 2017.10.25 45880