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    제목 Multifunctional Multiferroics (Multifunctional Multiferroics)
    TYPE 특별 강연
    DATE/TIME 2005-11-28 ~ 2005-11-28
    PLACE APCTP Seminar Room (APCTP Seminar Room)
    SPEAKER Prof. Sang-Wook Cheong (Prof. Sang-Wook Cheong)
    AFFILIATION Rutgers University (Rutgers University)
    * 주제 : Multifunctional Multiferroics
    * 연사 : 정상욱 교수
    * 소속 : (미국 Rutgers대학교 물리학과)
    * 일시: 2005년 11월 28일(월) 오후 3시 
    * 장소: 무은재 기념관 512호(APCTP 세미나실) 
    * 주최 : 아태이론물리센터(APCTP), 포스텍 이론물리 연구소(PCTP)  

    * Title : Multifunctional Multiferroics
    * Speaker : Prof. Sang-Wook CHEONG
    * Affiliation : Department of Physics & Astronomy Rutgers University
    * Date : Nov. 28(Mon), 2005  
    * Place: APCTP Seminar Room
    * Hosted by APCTP. POSTECH    
    * Abstract : 
    Ferroelectric and magnetic materials have been a time-honored subject of study and have led to some of the most important technological advances to date. Magnetism and ferroelectricity are involved with local unpaired spins and local dipoles (originating from off-center structural distortions), respectively.  These two seemingly unrelated phenomena can coexist in certain unusual materials, termed multiferroics. Despite the possible coexistence of ferroelectricity and magnetism, a pronounced interplay between these properties has rarely been observed. This has prevented the realization of multiferroic devices offering such functionality. We will discuss newly-discovered, extraordinary coupling 
    between spin and lattice degrees of freedom in a certain class of multiferroics. For example, the highly reproducible electric polarization reversal in TbMn2O5 and TbMnO3 and unprecedented large change of dielectric constant in DyMn2O5 and DyMnO3 can be activated by an applied magnetic field (H).  In addition, acoustic phonons in hexagonal-HoMnO3 can be significantly influenced by H. These manifestations of giant spin/lattice coupling provide new device concepts with tunable multifunctionality.