korean english


Home > 게시판 > 세미나

○ 일시: 7월 12일(화) 오전 11:00

○ 장소: 기초과학연구소 세미나실 (31317호)

○ 연사: 이  상  현  박사님 (High Energy Accelerator Research Organization (KEK) )

Title: Spin-direction-dependent magnetoelastic coupling on MnO, CoO, and NiO

○ Abstract: 

High resolution time-of-flight neutron diffraction and group theory resolved not only the long-standing problems of magnetic structure and phase transition mechanism in MnO, CoO, and NiO but also the issue of general symmetry in magnetic moment [1, 2]. Exchangestriction and new magnetostriction, so-called dipolar-magnetostriction and roto-magnetostriction, that induce phase transition from paramagnetic rocksalt structure to common C2/m monoclinic structure with magnetic propagation vector km=(0 1 0.5). We classify those into two groups by Γ1+(Ag)=(0, My, 0) and Γ2+(Bg)=(Mx, 0, Mz) spin direction in the order-parameter vector diagram. Time-reversal symmetry breaking causes discontinuous phase transition with linear-quadratic coupling Δβ~M2 between monoclinic angle Δβ and magnetic moment M. However, CoO and NiO show continuous phase transition with linear-cubic coupling Δβ~M3 forbidden by time-reversal symmetry. To the best of our knowledge, this is first experimental evidence that both magnetic moment and structural distortion can belong to same irreducible representation. Time-reversal symmetry prohibits same irreducible representation between them. The experimental results open a way to find new physics forbidden by time-reversal symmetry in condensed matter physics and material science.

번호 제목 날짜 조회 수
공지 <12/8(Thu.) 11:00am>노벨상 소개 강연 - 2016년 노벨 물리학상: 위상 응집 물리의 탄생 2016.11.28 1090480
102 <Sep. 18(Fri.) 4:00 PM> Special seminar 2015.09.16 59362
101 학술세미나 개최 안내: Local Modes in Vibrational (and Rotational) Spectroscopy file 2015.10.01 56685
100 <Oct. 20(Tue.) 2:00 PM> High-throughput Synthesis of Oxide Thin Films 2015.10.05 150844
99 <Oct.15(Thu) 16:30> Single-Molecule Approach to Homology Search & Strand Exchange in Homologous Recombination 2015.10.12 127117
98 <Oct.20(Tue) 16:00> Electromagnetic Response and Thermomagnetic Instabilities in Three-Dimensional Nanostructured Superconductors file 2015.10.15 104191
97 <Oct.20(Tue) 10:00-12:00> Novel quantum transport in Weyl semimetals and double-Weyl semimetals 2015.10.23 96922
96 <Nov.13(Fri) 16:00> Kondo screening in mixed valence and heavy fermion compounds and the signatures of Nozieres’ exhaustion 2015.11.04 135001
95 <Dec.30(Wed) 16:30> Some basics about the thermoelectricity; the semi-classical Boltzmann transport approach 2015.12.24 70252
94 <March 8(Tue) 18:00> Unsolved puzzles of Gamma-Ray Bursts 2016.03.03 75033
93 <March.18(Fri) 11:00> High Pressure Synthesis and Characterization of Non-Oxide Superconductors 2016.03.14 71886
92 <March.24(Thu) 14:00> A new boson and muon g-2 2016.03.17 68138
91 <4/6(Wed.) 1pm> Results from DM-Ice17 2016.04.05 83916
90 <April 25(Mon) 16:30> Neutron Recoil Polarization in Low‐energy Photodisintegration of the Deuteron 2016.04.25 54212
89 <May.27(Fri.) 10:00> Towards Magnetic 2D Materials 2016.04.27 90249
88 <6/24(Fri.) 1:30pm>Emergent geometry from field theory: Wilson's renormalization group revisited 2016.06.20 70325
» <7/12(Tue.) 11:00> Spin-direction-dependent magnetoelastic coupling on MnO, CoO, and NiO file 2016.07.01 79552
86 <7/15(Fri.) 14:00> Electronic quasiparticles in the quantum dimer model 2016.07.12 71724
85 <7/15(Fri.) 11:00> Observation of a field induced quantum spin liquid in α-RuCl3 2016.07.14 70062
84 <7/18(Mon.) 14:00> GEANT4 Particle Physics Simulation Software: A Brief Overview From a User’s Perspective 2016.07.15 69901
83 <8/5(Fri.) 10:30> Phase Slips in Superfluid Spin Transport in Magnetic Wires 2016.08.02 58087