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 1089856
517 <10/22(Tue.)>To p or not to p? – 17O NMR of Sr2RuO4 under strain file 2019.10.17 103734
516 <12/3> Magnetic couplings, optical spectra, and spin-orbit exciton in 5d Mott insulator Sr2IrO4 2012.11.26 103562
515 <7/15> Experiment for Discoveries of Extrasolar Planets 2009.07.13 103208
514 <2/14> Complex network models for mobile ad hoc networks 2011.02.11 103158
513 영어초록 예시 2008.03.18 102985
512 <12/19> The BLG Theory in Light-Cone Superspace 2009.12.15 102877
511 <2/8(Fri) 11:0 am ~ >Intertwined states in the pure and Nd-doped heavy fermion superconductor CeCoIn5 2019.02.08 102876
510 <2/27> Carbon nanotubes as Electron Sources 2006.02.21 102845
509 <7/20(Fri.) 4:00pm>Manufacturing next generation cryogen-free 1.5T MRI and cryogen-free NMR 2018.07.16 102639
508 <5/11>Emergent Geometry as Quantum Gravity 2009.05.07 102497
507 <6/5> BK 석학초청 특별강연 - How Well Does High Field Specific Heat Probe the Nodal Nature of the Multi- 2012.05.14 101675
506 <11/11> Revealing magnetism of nanoislands with quantitative insights into spin-polarized scanning tunneling spectroscopy 2013.11.05 101655
505 <11/14> Resonance collective mode in novel superconductors 2008.11.11 101532
504 <5/12(월)> Nanoscale probing of electrochemical phenomena and ionic dynamics by scanning probe microscopy 2014.05.07 101527
503 <5/18> Three magics to hold an atom without perturbation 2011.05.09 101247
502 <6/19> 초전도 특별세미나 2012.06.11 101171
501 <10/10>Self-reconfigurable robots 2008.10.07 101011
500 <8/19(Mon) 13:30 ~ >Detection of cosmic rays in the PeV to EeV energy range file 2019.08.16 100992
499 <6/18> A consistent truncation of D=11 supergravity to D=4, N=2 supergravity using wrapped M5-branes 2010.06.10 100989
498 <4/10> Mapulation of spins in organic compounds 2013.04.03 100868