Neutron scattering study of spin-dependent quantum states in triangular antiferromagnets

2013 Fiscal Year Final Research Report

• Project/Area Number: 24740223
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Condensed matter physics II
• Research Institution: Tohoku University
• Principal Investigator: NAMBU Yusuke 東北大学, 多元物質科学研究所, 助教 (60579803)
• Project Period (FY): 2012-04-01 – 2014-03-31
• Keywords: フラストレート磁性体 / 中性子散乱 / 三角格子反強磁性体 / 籠目格子反強磁性体 / 巨視的量子状態

Research Abstract

Geometrical frustration has attracted a lot of interest because of a potential emergence of novel quantum states. To elucidate spin-dependent macroscopic quantum states, neutron scattering measurements were performed on frustrated magnets. In triangular antiferromagnets with spin-1 and 2, inelastic and polarized elastic neutron scattering measurements reveal the possible existence of magnetic quadrupole interactions. Indeed, our experimental findings cannot be explained by simple spin-spin exchange interactions. In addition, we have applied inelastic neutron scattering on spin-1/2 Kagome antiferromagnets. Through detailed study of magnetic excitations, singlet-triplet excitations and its magnetic field evolution, and renormalization of excitation energy predicted by the linear spin wave theory due to quantum effects are clarified.

Research Products

• [Journal Article] Large Negative Quantum Renormalization of Excitation Energies in the Spin-1/2 Kagome Lattice Antiferromagnet Cs_2Cu_3SnF_<12> (2014)
  • Author(s): T. Ono, K. Matan, Y. Nambu, T.J. Sato, K. Katayama, S. Hirata, H. Tanaka
  • Journal Title: J. Phys. Soc. Jpn. Volume: 83 Pages: 043701
  • DOI: 10.7566/JPSJ.83.043701
  • Peer Reviewed
• [Journal Article] Ghost modes and continuum scattering in the dimerized distorted kagome lattice antiferromagnet Rb_2Cu_3SnF_12 (2014)
  • Author(s): K. Matan, Y. Nambu, Y. Zhao, T.J. Sato, Y. Fukumoto, T. Ono, H. Tanaka, C. Broholm, A. Podlesnyak, G. Ehlers
  • Journal Title: Phys. Rev. B Volume: 89 Pages: 024414
  • DOI: 10.1103/PhysRevB.89.024414
  • Peer Reviewed
• [Journal Article] 三角格子反強磁性体NiGa_2S_4の二次元磁性 (2013)
  • Author(s): 南部雄亮
  • Journal Title: 波紋 Volume: 23 Pages: 23-28
  • Peer Reviewed
• [Journal Article] Spin dynamics and spin freezing in the triangular lattice antiferromagnets FeGa_2S_4 and NiGa_2S_4 (2012)
  • Author(s): S. Zhao, P. Dalmas de Réotier, A. Yaouanc, D.E. MacLaughlin, J.M. Mackie, O.O. Bernal, Y. Nambu, T. Higo, S. Nakatsuji
  • Journal Title: Phys. Rev. B Volume: 86 Pages: 064435
  • DOI: 10.1103/PhysRevB.86.064435
  • Peer Reviewed
• [Journal Article] 中性子散乱による磁気構造解析 (2012)
  • Author(s): 南部雄亮
  • Journal Title: 表面科学 Volume: 33 Pages: 302-307
  • Peer Reviewed
• [Journal Article] Block magnetism coupled with local distortion in the iron-based spin-ladder compound BaFe_2Se_3 (2012)
  • Author(s): Y. Nambu, K. Ohgushi, S. Suzuki, F. Du, M. Avdeev, Y. Uwatoko, K. Munakata, H. Fukazawa, S. Chi, Y. Ueda, T.J. Sato
  • Journal Title: Phys. Rev. B Volume: 85 Pages: 064413
  • DOI: 10.1103/PhysRevB.85.064413
  • Peer Reviewed
• [Presentation] FullProfを用いた粉末試料の磁気構造解析 (2013)
  • Author(s): 南部雄亮
  • Organizer: 平成25年度茨城県中性子利用促進研究会磁石材料のその場構造解析分科会
  • Place of Presentation: エッサム神田ホール
  • Year and Date: 2013-10-22
  • Invited
• [Presentation] Excitations under fields of the pinwheel valence bond solid state in the Kagomé antiferromagnet Rb_2Cu_3SnF_<12> (2013)
  • Author(s): Y. Nambu, K. Matan, Y. Zhao, T. Ono, Y. Fukumoto, A. Podlesnyak, G. Ehlers, J.W. Lynn, T.J. Sato, C. Broholm, H. Tanaka
  • Organizer: International Conference on Neutron Scattering 2013
  • Place of Presentation: Edinburgh International Conference Cnetre, Edinburgh, UK
  • Year and Date: 2013-07-11
• [Presentation] 籠目格子反強磁性体Rb_2Cu_3SnF_12における一重項⋅三重項励起の磁場依存性 (2013)
  • Author(s): 南部雄亮, K. Matan, Y. Zhao,小野俊雄,福元好志, A. Podlesnyak, G. Ehlers, J. Lynn,佐藤卓, C. Broholm,田中秀数
  • Organizer: 日本物理学会第68回年次大会
  • Place of Presentation: 広島大学東広島キャンパス
  • Year and Date: 2013-03-26
• [Presentation] SENJUにおけるこれからの磁気構造解析 (2013)
  • Author(s): 南部雄亮
  • Organizer: 第5回CROSSroads研究会「J-PARCの単結晶回折計による構造物性研究」
  • Place of Presentation: KEK東海キャンパス
  • Year and Date: 2013-02-25
  • Invited
• [Presentation] Spin Dynamics of the 2D Magnet NiGa_2S_4 (2012)
  • Author(s): Y. Nambu
  • Organizer: Nikko Joint Conference between 10th International Conference on Quasielastic Neutron Scattering (QENS) and 5th Workshop on Inelastic Neutron Spectrometers (WINS)
  • Place of Presentation: Nikko Public Meeting Hall
  • Year and Date: 2012-10-04
  • Invited
• [Presentation] 三軸分光器CTAX @ ORNLの現状と一次元構造をもつ鉄系化合物の磁性 (2012)
  • Author(s): 南部雄亮
  • Organizer: 中性子セミナー
  • Place of Presentation: 東京大学物性研究所
  • Year and Date: 2012-06-15
• [Remarks]
  • URL: http://www.jps.or.jp/books/jpsjselectframe/2014/files/14-04-2.pdf