Spin dynamics of iron-based superconductors studied by inelastic pulse neutron scattering -origin of localize and itinerant nature-

• Project/Area Number: 16K17750
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Condensed matter physics II
• Research Institution: Okayama University
• Principal Investigator: Horigane Kazumasa 岡山大学, 異分野基礎科学研究所, 准教授 (10406829)
• Project Period (FY): 2016-04-01 – 2018-03-31
• Project Status: Completed (Fiscal Year 2017)
• Budget Amount: ¥3,640,000 (Direct Cost: ¥2,800,000、Indirect Cost: ¥840,000); Fiscal Year 2017: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000); Fiscal Year 2016: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
• Keywords: 鉄系超伝導体 / パルス中性子 / 磁気励起 / 単結晶育成 / Flux法 / 磁性 / 超電導材料

Outline of Final Research Achievements

Understanding the overall features of magnetic excitation is essential for clarifying the mechanism of Cooper pair formation in iron-based superconductors. Here we report a study on the spin fluctuations of the hole-overdoped iron-based superconductors Ba1-xKxFe2As2 (x = 0.5 and 1.0; Tc = 36 K and 3.4 K, respectively) over the entire Brillouin zone using inelastic neutron scattering. We found that their spin spectra consist of spin wave and chimney-like dispersions. The chimneylike dispersion can be attributed to the itinerant character of magnetism. The band width of the spin wave-like dispersion is almost constant from the non-doped to optimum-doped region, which is followed by a large reduction in the overdoped region. This suggests that the superconductivity is suppressed by the reduction of magnetic exchange couplings, indicating a strong relationship between magnetism and superconductivity in iron-based superconductors.

Research Products

• [Int'l Joint Research] 浦項工科大学校(韓国)
• [Journal Article] Magnetic phase diagram of Sr2-xLaxIrO4 synthesized by mechanical alloying (2018)
  • Author(s): K. Horigane, M. Fujii, H. Okabe, K. Kobayashi, R. Horie, H. Ishii, Y. F. Liao, Y. Kubozono, A. Koda, R. Kadono, and J. Akimitsu
  • Journal Title: Phys. Rev. B Volume: 97 Issue: 6 Pages: 064425-064425
  • DOI: 10.1103/physrevb.97.064425
  • NAID: 130007647215
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Spin excitations in hole-overdoped iron-based superconductors (2016)
  • Author(s): K. Horigane, K. Kihou, K. Fjita, R. Kajimoto, K. Ikeuchi, S. Ji, J. Akimitsu, C. H. Lee
  • Journal Title: Sci. Rep. Volume: 6 Issue: 1 Pages: 333031-6
  • DOI: 10.1038/srep33303
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Presentation] Spin resonance of Ba1-xKxFe2As2 studied by neutron scattering (2017)
  • Author(s): C. H. Lee, K. Kihou, J. T. Park, K. Horigane, F. Waßer, N. Qureshi, Y. Sidis, J. Akimitsu, M. Braden
  • Organizer: APS March Meeting 2017
  • Place of Presentation: New Orleans (USA)
  • Year and Date: 2017-03-13
  • Int'l Joint Research
• [Presentation] Spin excitations in hole-overdoped iron-based superconductors Ba1-xKxFe2As2 (2017)
  • Author(s): K. Horigane, K. Kihou, K. Fjita, R. Kajimoto, K. Ikeuchi, S. Ji, J. Akimitsu and C. H. Lee
  • Organizer: APS March Meeting 2017
  • Place of Presentation: New Orleans (USA)
  • Year and Date: 2017-03-13
  • Int'l Joint Research
• [Presentation] オーバーホールドープ領域におけるBa1-xKxFe2As2の磁気励起 (2017)
  • Author(s): 堀金和正
  • Organizer: MLFチョッパーユーザーミーティングDirection2017
  • Invited
• [Presentation] Spin excitations in hole-overdoped Fe-based superconductors (2017)
  • Author(s): C. H. Lee, K. Horigane, K. Kihou, J. T. Park, F. Waßer, N. Qureshi, Y. Sidis, R. Kajimoto, K. Ikeuchi, S. Ji, J. Akimitsu and M. Braden
  • Organizer: SCES 2017
  • Int'l Joint Research
• [Presentation] Crystal structure and superconducting properties of KSr2Nb3O10 (2017)
  • Author(s): T. Kawaguchi, K. Horigane, Y. Itoh, K. Kobayashi, R. Horie, T. Kambe, J. Akimitsu
  • Organizer: SCES 2017
  • Int'l Joint Research
• [Presentation] 5d transition-metal superconductor SrIr2 (2017)
  • Author(s): R. Horie, S. Nishiyama, M. Akimitsu, K. Horigane, K. Kobayashi, T. Kambe, Y. Kubozono, J. Akimitsu
  • Organizer: 28th International Conference on Low Temperature Physics
  • Int'l Joint Research
• [Presentation] 層状Nb酸化物AB2Nb3O10の構造と超伝導 (2017)
  • Author(s): 川口貴弘, 堀金和正, 伊藤雄吾, 小林夏野, 神戸高志, 秋光純
  • Organizer: 日本物理学会第73回年次大会
• [Presentation] メカニカルアロイ法によるSr2-xlaxIrO4の磁気相図 (2017)
  • Author(s): 堀金和正、藤井正徳、岡部博孝、小林夏野、堀江理恵、石井啓文、廖彦發、久保園芳博、幸田章宏、門野良典、秋光純
  • Organizer: 日本物理学会第73回年次大会
• [Presentation] オーバーホールドープ領域におけるBa1-xKxFe2As2の磁気励起 (2016)
  • Author(s): 堀金和正、木方邦宏、藤田慧、梶本亮一、池内和彦、池聖大、秋光純、李哲虎
  • Organizer: 第10回 物性科学領域横断研究会
  • Place of Presentation: 神戸大学（百年記念館）
  • Year and Date: 2016-12-09
• [Presentation] オーバーホールドープ領域におけるBa1-xKxFe2As2の磁気励起 (2016)
  • Author(s): 堀金和正、木方邦宏、藤田慧、梶本亮一、池内和彦、池聖大、秋光純、李哲虎
  • Organizer: 日本中性子科学会第16回年会
  • Place of Presentation: 名古屋大学（豊田講堂）
  • Year and Date: 2016-12-01
• [Presentation] ホールオーバードープ(Ba,K)Fe2As2のスピンレゾナンス (2016)
  • Author(s): 李哲虎、木方邦宏、J. T. Park、堀金和正、藤田慧、F. Waßer、 N. Qureshi、 Y. Sidis、秋光純、M. Braden
  • Organizer: 日本中性子科学会第16回年会
  • Place of Presentation: 名古屋大学（豊田講堂）
  • Year and Date: 2016-12-01
• [Presentation] Spin excitations in hole-overdoped iron-based superconductors (2016)
  • Author(s): K. Horigane, K. Kihou, K. Fjita, R. Kajimoto, K. Ikeuchi, S. Ji, J. Akimitsu and C. H. Lee
  • Organizer: ICMM2016 Satellite Meeting NFM2016
  • Place of Presentation: 広島市文化交流会館
  • Year and Date: 2016-09-09
  • Int'l Joint Research / Invited
• [Remarks] BL01 ホール過剰ドープした鉄系超伝導体における磁気励起
  • URL: https://j-parc.jp/researcher/MatLife/ja/monthly_reports/2016_09.html