10 GPa high pressure NMR study of Fe based high temperature superconductor

2011 Fiscal Year Final Research Report

• Project/Area Number: 21540351
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Condensed matter physics II
• Research Institution: Chiba University
• Principal Investigator: KOBORI Yoh 千葉大学, 大学院・理学研究科, 教授 (10153660)
• Co-Investigator(Kenkyū-buntansha): FUKAZAWA Hideto 千葉大学, 大学院・理学研究科, 准教授 (90361443)
• Co-Investigator(Renkei-kenkyūsha): TAKESHITA Nao 産業技術総合研究所, 主任研究員 (60292760)
• Project Period (FY): 2009 – 2011
• Keywords: 鉄系高温超伝導体 / 高圧実験 / NMR/NQR / BaFe2As2 / KFe2As2

Research Abstract

NMR/NQR and specific heat measurements of (Ba_<1-x>K_x)Fe_2As_2 were performed using high quality single crystals at ambient and high pressure. The superconducting gap in KFe_2As_2 has a multi- gap structure consisted of large and very small gaps. We found that a larger gap had a line-node structure. NMR study in (Ba_<1-x>K_x)Fe_2As_2 showed that the superconducting gap structure changed very smoothly with increasing x for x > 0.4. The superconductivity appears above 15 GPa in BaFe_2As_2 associated with disappearance of anti-ferromagnetic order. The phase change is extremely sensitive to pressure in homogeneity.

Research Products

• [Journal Article] Potential Antiferromagnetic Fluctuations in Hole-Doped Iron-Pnictide Superconductor Ba_<1-x>K_xFe_2As_2 Studied by <75>^As NuclearMagnetic Resonance Measurement (2012)
  • Author(s): M. Hirano. Y. Yamada. T. Saito. R. Nagashima. T. Konishi. T. Toriyama. Y. Ohta. H. Fukazawa. Y. Kohori. Y. Furukawa. K. Kihou. C.-H. Lee. A. Iyo. H. Eisaki
  • Journal Title: J. Phys. Soc Volume: Jpn. 81 Pages: 054704-1-10
  • Peer Reviewed
• [Journal Article] Pressure and K doping induced superconductivity in BaFe_2As_2 (2011)
  • Author(s): T. Yamazaki. N. Takeshita. R. Kobayashi. T. Saito. Y. Yamada. K. Kondo. M. Hirano. H. Fukazawa. Y. Kohori. K. Kihou. C. H. Lee. H. Kito. A. Iyo H. Eisaki
  • Journal Title: J. Phys.: Conf Volume: Ser.273 Pages: 012041-1-4
  • Peer Reviewed
• [Journal Article] Fast Spin Fluctuation Viewed by Muon Spin Relaxation in Optimally Doped and Overdoped Iron-Based Oxypnictide Superconductors LaFeAsO_<1-x>F_x (2011)
  • Author(s): K. Ohishi. Y. Ishii. K. Miyazawa. H. Fukazawa. I. Watanabe. Y. Kohori. P. M. Shirage. H. Kito. A. Iyo. H. Eisaki
  • Journal Title: J. Phys. Soc Volume: Jpn. 80 Pages: 024703-1-5
  • Peer Reviewed
• [Journal Article] Gap in KFe_2As_2 studied by small-angle neutron scattering observations of the magnetic vortex Lattice (2011)
  • Author(s): H. Kawano-Furukawa. C. J. Bowell. J. S. White. R. W. Heslop. A. S. Cameron. E. M. Forgan. K. Kihou. C. H. Lee. A. Iyo. H. Eisaki. T. Saito. H. Fukazawa. Y. Kohori. R. Cubitt. C. D.Dewhurst. J. L. Gavilano M. Zolliker
  • Journal Title: Phys. Rev Volume: B 84 Pages: 024507-1-9
  • Peer Reviewed
• [Journal Article] Cyclotron Resonance and Mass Enhancement by Electron Correlation in KFe_2As_2 (2011)
  • Author(s): M. Kimata. T. Terashima. N. Kurita .H. Satsukawa. A. Harada. K. Kodama. K. Takehana. Y. Imanaka. T. Takamasu. K. Kihou. Chul-Ho Lee. H. Kito. H. Eisaki. A. Iyo. H. Fukazawa. Y. Kohori. H. Harima S. Uji
  • Journal Title: Phys. Rev Volume: Lett. 107 Pages: 166402-1-5
  • Peer Reviewed
• [Presentation] 単結晶Ba1-xKxFe2As2(x=0-0.31)の圧力効果II (2012)
  • Author(s): 國分光胤, 小牧泰大, 富沢裕樹, 山崎岳洋, 小林良介, 齊藤拓, 深澤英人, 小堀洋, 竹下直, 木方邦宏, 李哲虎, 伊豫彰, 永崎洋
  • Organizer: 日本物理学会第67回年次大会
  • Place of Presentation: 関西学院大学
  • Year and Date: 2012-03-25
• [Presentation] 単結晶Ba_<1-x>K_xFe_2As_2のK高濃度領域の<75>^As-NMR/NQR II (2012)
  • Author(s): 長澤洋平, 平野将記, 山田佑自, 齊藤拓, 長島亮, 深澤英人, 小堀洋, 木方邦宏, 李哲虎, 伊豫彰, 永崎洋
  • Organizer: 日本物理学会第67回年次大会
  • Place of Presentation: 関西学院大学
  • Year and Date: 2012-03-25
• [Presentation] 重い電子系化合物Ce_2PdIn_8の<115>^In-NQRによる研究II (2012)
  • Author(s): 長島亮, 島谷奨, 深澤英人, 小堀洋, D. Kaczorowski
  • Organizer: 日本物理学会第67回年次大会
  • Place of Presentation: 関西学院大学
  • Year and Date: 2012-03-24
• [Presentation] 重い電子系化合物Ce_2PdIn_8の<115>^In-NQRによる研究 (2011)
  • Author(s): 長島亮, 深澤英人, 小堀洋, D. Kaczorowski
  • Organizer: 日本物理学会2011年秋季大会
  • Place of Presentation: 富山大学
  • Year and Date: 2011-09-25
• [Presentation] Ba_<1-x>K_xFe_2As_2(x=0.27-1)の<75>^As-NMR/NQR (2011)
  • Author(s): 平野将記, 山田佑自, 齊藤拓, 村野悠一郎, 長島亮, 深澤英人, 小堀洋, 木方邦宏, 李哲虎, 伊豫彰, 永崎洋
  • Organizer: 日本物理学会2011年秋季大会
  • Place of Presentation: 富山大学
  • Year and Date: 2011-09-22
• [Presentation] NMR study of hole-doped iron-pnictide superconductor Ba_<(1-x)>K_xFe_2As_2(x = 0.27-1) (2011)
  • Author(s): M. Hirano. Y. Yamada. T. Saito. Y. Murano. R. Nagashima. H. Fukazawa. Y. Kohori. K. Kihou. C. H. Lee. A. Iyo. H. Eisaki
  • Organizer: 26th International Conference on Low Temperature Physics(LT26)
  • Place of Presentation: 北京
  • Year and Date: 2011-08-16